Wearable Chemical Sensors: Present ... - American Chemical Society

Subscriber access provided by - Access paid by the | UCSB Libraries

Perspective

Wearable Chemical Sensors: Present Challenges and Future Prospects Amay Jairaj Bandodkar, Itthipon Jeerapan, and Joseph Wang ACS Sens., Just Accepted Manuscript • DOI: 10.1021/acssensors.6b00250 • Publication Date (Web): 06 May 2016 Downloaded from http://pubs.acs.org on May 8, 2016

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

ACS Sensors is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

Wearable Chemical Sensors: Present Challenges and Future Prospects Amay J. Bandodkar, Itthipon Jeerapan, Joseph Wang* Department of NanoEngineering, University of California, San Diego La Jolla, CA 92093, USA. *E-mail: [email protected]; Fax: +1 (858) 534 9553; Tel: +1 (858) 246 0128

Abstract Wearable sensors have received considerable interest over the past decade owing to their tremendous promise for monitoring the wearer’s health, fitness and his surroundings. However, only limited attention has been directed at developing wearable chemical sensors that offer more comprehensive information about a wearer’s well-being. The development of wearable chemical sensors is faced with multiple challenges on various fronts. This article reviews key challenges and technological gaps towards the successful realization of effective wearable chemical sensor systems, related to materials, power, analytical procedure, communication, and data acquisition, processing, and security. Size, rigidity and operational requirements of present chemical sensors are incompatible with wearable technology. Sensor stability and on-body sensor surface regeneration constitute key analytical challenges. Similarly, present wearable power sources are incapable of meeting the requirements for wearable electronics owing to their low energy densities and slow recharging. Several energy-harvesting methodologies have inherent issues, including inconsistent power supply and limited stability. There are also major challenges pertaining to handling and securing the big data generated by wearable sensors. These include achieving high data transfer rates and efficient data mining. Efforts must also be made towards developing next generation cryptologic algorithms for ensuring data security and user privacy. The challenges facing the field of wearable chemical sensors, and wearable sensors, in general, can thus be addressed only by a multi-disciplinary approach where researchers from diverse fields work in unison. The article discusses these challenges and their potential solutions along with future prospects. Keywords: Wearable electronics, Chemical sensors, Internet of Things, Non-invasive monitoring, Bio-integrated devices.

The interest in the field of Internet-of-Things (IoT) has witnessed an exponential growth over the past decade as markets realize the true potential of real-time data acquisition for various entertainment,1 knowledge dissemination,2 defense,3 environmental4-5 and healthcare6-8 applications. Medical applications of IoT have received the greatest attention since real-time 1 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

monitoring of physiologically relevant parameters is crucial not only in critical hospital settings9 but also during routine daily activities.7, 10 Such continuous vital information can alert the user about health abnormalities towards taking precautionary steps and circumventing severe medical situations.7 Wearable sensors can play a pivotal role in IoT in healthcare as these devices provide new avenues to continuously monitor individuals and hence provide the wearer with vital physiological information regarding his health in a personalized fashion.11-16 Wearable sensors are not limited to only on-body applications; these devices can have much broader scope when integrated with other surfaces, such as buildings or vehicles. However, in the present article we will focus only on human-body integrated wearable chemical sensors. Although the importance of wearable sensors is widely known, the field has experienced unbalanced advances in research and development. Existing wearable sensors commonly track the user’s physical activities and vital signs (such as heart rate), with early research efforts focusing on developing wearable sensors that can monitor temperature,17 body motion,18-20 or ECG.21-22 However, continuous monitoring of chemical parameters is crucial in order to obtain complete information about a wearer’s health, performance or stress at the molecular level. Recognizing the significance of wearable chemical sensors, several groups have demonstrated recently that such devices that can monitor electrolytes,14, 23-26 metabolites,27-32 heavy metals33-34 and toxic gases35-38 directly on the body in various biofluids, such as sweat,23-25, 27, 29, 31 tears,39-42 and saliva.28, 43-44 Researchers have also developed wearable epidermal sensors that can monitor wound healing.45-47 Several review articles discussing these developments have been published recently.13, 15, 48-58 Though recent advances in wearable chemical sensors are encouraging, unfortunately, at present, these developments have not matched the rapid progress and commercial success achieved by wearable physical sensors. The present article focuses on key challenges that the field of wearable chemical sensors is facing and the possible solutions to these. The bottlenecks in the wearable sensors domain can be broadly classified into challenges in materials, power, data acquisition, processing, security, communication and analytical requirements (Figure 1). Our goal is not to review the actual wearable chemical sensors developed recently as these devices were reviewed in several articles.13, 48-58 but rather to discuss the challenges and gaps towards the successful realization of effective wearable chemical sensor systems. In the present article, each of these challenges will be further divided into sub-categories to discuss these issues in detail. A significant part of the article aims at describing potential solutions to the key problems encountered by wearable chemical sensors via advances in related fields, and routes to incorporate them onto such sensor platforms. Finally, we will discuss the future prospects of this emerging sensor field and its ability to open up new avenues in the field of wearable electronics.

Present Challenges and Possible Solutions 1. Material Aspects 2 ACS Paragon Plus Environment

Page 2 of 46

Page 3 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

1.1 Materials-based challenges 1.1.1 Mechanical properties-based challenges Limitations due to the absence of viable materials for realizing high performance devices are ones of the most critical challenges in the field of wearable chemical sensors. Although state-ofthe-art chemical sensors have been in the markets for several decades, the materials, fabrication techniques and device form-factor utilized for developing such traditional sensors are often incompatible for realizing their wearable counterparts. For example, conventional chemical sensors are bulky and heavy59-62 and hence cannot be used for wearable applications. Thus, in order to target the wearables market, there is a need to develop sensors that are small and light for seamless integration with the human body for daily life. Similarly, common chemical sensors are fabricated on rigid surfaces and therefore they cannot be easily mated with the soft, curvilinear human tissues.50, 63 Conformal contact between the device and the tissue is also essential for acquiring low noise sensor response. This is especially true in cases of wearable/implantable devices that are intended to integrate with highly nonlinear biological structures, such as sensors for brain activity monitoring, or ocular sensors. The rigidity of conventional chemical sensors leads also to poor mechanical resiliency against repeated complex deformations commonly experienced by the human body. The human tissue is soft and curvilinear in nature and undergoes regular multi-axes deformations. Recognizing the rigidity of existing chemical sensors, direct chemical sensing on the skin requires soft and stretchable sensor materials able to conform to the non-planar features characteristic of human anatomy. The wearable chemical sensors thus must have mechanical properties similar to the tissues so that they can be anatomically compliant with the contours of the skin, without causing any somatosensory response. 1.1.2

Self-destroyed and invisible sensors-based challenges

In several scenarios, e.g. implantable chemical sensors, the devices must be surgically removed after their mission is achieved. This leads to undesired additional steps. Some complications may also occur if the organs/tissue gets damaged during removal of the device or a situation may occur wherein some components of the device are failed to be removed. Scenarios related to accidental in-vivo breaking of the implanted device, leading to shards of the broken pieces damaging surrounding organs are also possible. At present, chemical sensors do not have the capability to circumvent such untoward incidents. As was mentioned earlier, the most attractive aspect of wearable chemical sensors is the opportunity to continuously monitor several parameters in order to provide a comprehensive idea about the wearer’s health. However, with increasing functionality, the device inevitably will have larger size. Furthermore, a major section of the consumers would prefer the wearable devices to be inconspicuous since wearing large and visibly noticeable devices is quite unattractive. Existing wearable sensors do not consider such important design parameter. Wearable chemical sensors represent a disruptive technology that 3 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

will bring about a paradigm shift in the chemical sensing domain. Product acceptance by the consumers depends on many factors beyond the analytical performance. For consumers to accept and use the new wearable sensor devices, they need to comfortably integrate into daily life with minimal user effort. High performance devices must also be aesthetically pleasing to gain rapid market diffusion. 1.2 Possible solutions for materials-based challenges 1.2.2 Addressing the mechanical stress challenge. The issue related to conformal contact between wearable chemical sensors and the human body can be resolved by matching the mechanical properties of the device with that of the human tissues. The human tissue is characterized as soft, stretchable and curvilinear with unique mechanical properties. In order to equate the mechanical properties of the device with that of the tissues, researchers have developed highly flexible plastic-31, 64-65 and textile-14, 25, 35 based wearable chemical sensors that can detect electrolytes,14, 24-25 metabolites,27, 29, 31 or volatile organic compounds.24, 35, 38 These advances are indeed commendable when one considers the high rigidity of conventional chemical sensors. However, the flexible plastics still have a huge mismatch as compared to human tissues. This can lead to skin irritation and even to device failure during body-motion induced mechanical deformations. On the other hand, textile-based sensors have mechanical properties much similar to that of the human skin, offering conformal contact between the body and the sensor. However, these fabrics can be in intimate contact with the skin only at limited locations. This restricts the utility of textile-based sensors for wide applications that mandate sensors to be located at places that are not usually covered with clothing. Soft, stretchable elastomers hold the answer to these challenges. Pioneering studies by Rogers6669 , Someya70-72 and Bao73-75 have demonstrated soft, stretchable and tissue-like electronic devices. However, these soft devices have been developed for measuring only physical parameters like pressure,70, 73, 75 electrophysiological signals,21-22, 68 or motion.18-20 Until recently, there were no examples of soft and stretchable wearable chemical sensors. Acknowledging the vitality of developing such tissue-mimicking chemical sensors, we recently demonstrated the first example of all-printed, highly stretchable electrochemical devices by engineering PEDOT:PSS and Ag/AgCl inks with Ecoflex, a silicone-based stretchable elastomeric binder, and Zonyl, a nonionic surfactant, to realize devices that could be stretched up to 100%.76 Indeed, this device’s ability to withstand the strains is sufficient for most of the wearable applications; however, there may be situations, such as sudden impact, that would warrant the need for developing devices that can bear exceptional levels of strains. We therefore developed a highly stretchable CNT-based, all-printed electrochemical device77 (Figure 2B). The printed device was able to endure strains as high as 500% with minimal effect on its electrochemical response, thus representing the highest level of stretchability offered by any printed device to 4 ACS Paragon Plus Environment

Page 4 of 46

Page 5 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

date. The device was fabricated using intrinsically stretchable inks in combination with freestanding serpentine interconnects. This allows the device to possess two levels of stretchability – 1) due to unwinding of free-standing serpentine structure (1st degree stretchability) and 2) due to intrinsic stretchability of printable inks based on ink formulation (2nd degree stretchability). The printed device was further functionalized with different reagents to realize highly stretchable ammonium ion and glucose sensors as well as a glucose biofuel cell. Although these examples of stretchable devices indicate considerable promise for developing skin-worn chemical sensors, much work needs to be done. Firstly, efforts must be devoted to match the mechanical properties exactly to that of the target tissue. For example, the human epidermis is characterized by a low-modulus response towards relative small strains (ε 15 min) and this weakens the chances of developing a continuous and rapid bio-affinity based wearable sensor. Furthermore, in order to achieve accurate and precise information, the bio-affinity sensors must be washed thoroughly after the incubation phase to reduce non-specific binding of interfering species to the sensor surface. Satiating this condition is again daunting in case of wearable applications with the need for human intervention. The concentrations of the chemical analytes that these wearable bio-affinity sensors are expected to detect are usually low (nM to aM range).101-102, 123 Thus, these sensors must offer very low limits of detection. This condition is inherently tied to the above mentioned challenges. For example, in order to achieve low limits of detection, the binding affinity of the receptor to its analyte must be strong; this implies that regeneration of the sensor surface will be extremely difficult. Similarly, low limit of detection mandates thorough washing of the sensor surface for mitigating non-specific adsorption – a complicating step for wearable application. Researchers achieve low limit of detection for bio-affinity sensors by relying on sandwich-based systems.113114, 122, 126 These are multi-step protocols which cannot be easily implemented using wearable platforms. 2.1.5

Multi-analyte Sensing

In many scenarios, one must monitor several parameters simultaneously in order to obtain a comprehensive idea about the wearer or its surrounding. For example, one must detect a whole host of chemical105 as well as physical127 parameters simultaneously128 for complete profiling of person’s well-being. Similarly, an array of chemicals must be detected for environmental105, 129130 and security107,131 applications. Such multiplexed detection commands the wearable devices to include a high density of individual, miniaturized chemical sensors on a single, small platform. 8 ACS Paragon Plus Environment

Page 8 of 46

Page 9 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

These multi-analyte sensor arrays must also possess negligible cross-talk between the individual sensors. Such independence of individual sensors in such wearable sensor arrays during multiplexed measurements is realized by using specific receptors, controlling their spacing and by electrically decoupling the operating points of each sensor’s interface. 2.2 Solutions for Operational Challenges 2.2.1 Addressing the pretreatment, stability and sensitivity challenges The need for pretreatment could arise from a variety of reasons. For example, in several scenarios, pretreatment of the sample solution is required to remove/separate chemicals that could interfere in a sensor’s response and thus lead to erratic results. Sensors that are highly selective towards the desired chemical and are unaffected by the presence of interfering molecules would address this issue. This could be achieved by using or developing highly selective receptors113,121, 132-133 and/or performing the separation on the transducer surface using variety of permselective coatings.134-135 In some cases, pretreatment becomes mandatory since the chemical analyte is present in a state that is incompatible with the sensor detection mode. A good example would be detection of heavy metals in solid samples. Conventionally, the sample is first digested in strong acidic media to extract the metals, followed by their quantification by a chemical sensor. Techniques, such as, abrasive stripping voltammetry, that obviate the need for such liquid handling136 could be explored, as was illustrated recently for wearable forensic applications.137-138 Even more challenging is the extraction of nucleic acids towards wearable DNA detection (e.g. food or forensic analyses). In several cases the sample concentration could lie beyond the detection range of the sensor, requiring sample preconcentration or dilution steps. This issue could be addressed by using protocols with ‘built-in’ accumulation steps33 or by relying on transducers of different sensitivities so that the detection limit is modulated for pretreatment-free analyte detection. Addressing the stability challenge depends on the nature of the component that affects the sensor stability the most. The strategy to overcome this challenge depends on the nature of the component that affects the sensor stability the most. In majority of the cases, the receptors, especially biological ones, are most susceptible to denaturation, leading to poor sensor stability. Incorporating stabilizing agents 139-140 or providing a biocompatible environment to the bioreceptors141-142 can mitigate this issue and improve the stability of the sensor. The sensitivity and limit of detection for a chemical sensor are quite important factors. Over the past decades numerable protocols have been developed to enhance these parameters.101102, 126 These include incorporating nano-materials,64, 108, 114, 143 developing target recycling and other amplification protocols, 144-146 and appropriate selection of transducers.147-149 Unfortunately, many of these protocols require procedures or instrumentation that would be challenging to incorporate on wearable platforms. 2.2.2

Solutions for Challenges in Bio-affinity Sensing 9 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 46

Considering the enormous opportunities that wearable bio-affinity chemical sensors have to offer, it is indubitable that researchers should put utmost efforts in developing strategies to address the challenges that have hindered the development of viable wearable bio-affinity sensors. The issue of degradation of bio-receptors could be addressed by developing synthetic abiotic receptors that match the sensing properties of bio-receptors sans the possibility of degeneration. Molecularly imprinted polymers149-151 and selective ligands133, 152-153 have shown some promise in this regard. However, to date they are unable to rival the specificity and binding affinity of their biological counterparts. With advances in the field of materials science and designer chemistry, it may be possible in near future to develop environmentally-insensitive synthetic receptors that possess high affinity, selectivity and stability. Coupling these synthetic affinity-based receptors with on-body micro-fluidic systems can also address issues related to rapid detection, regeneration and washing step. The synthetic receptors can be designed in a manner that bond rapidly to the analyte in a reversible fashion. The rapid binding should reduce the detection time while the reversible nature should enable convenient regeneration towards repetitive use.114, 154 Researchers have already developed aptamers whose binding affinity can be easily modulated to meet specific requirements.110, 122 Researchers could look into such approaches to develop rapid response sensors. The field of micro-fluidics has experienced phenomenal advances that have led to the realization of complex microsystems for sensor regeneration.122, 155 Integrating such micro-fluidic systems onto wearable platforms can address the challenges of on-body regeneration and washing steps inherent to bio-affinity sensors for continuous monitoring.156-157 2.2.3 Meeting the Multi-Analyte Sensing Challenges Multi-analyte chemical sensor arrays have been investigated for several decades.38, 158-161 Thus, a huge wealth of information is already available in the scientific domain for realizing multianalyte wearable chemical sensors. Recently, we demonstrated a highly stretchable, textile-based dual potentiometric sensor that could be used for simultaneously detecting sodium and potassium in the human sweat.14 The same platform can be easily extended for incorporating the additional electrochemical sensor modalities (e.g. amperometry) on the same platform. Similarly, Gao et al. reported a multi-analyte flexible wearable sensor that can simultaneously detect the glucose and lactate metabolites along with sodium and potassium electrolytes.29 Though these studies are engaging, much needs to be done for dense integration of multiple sensors on a small wearable platform. Nanotechnology has revealed the potential for developing miniaturized multi-analyte chemical sensors that have extremely low detection limits.158 In addition to decreasing the dimension, researchers should devote their attention towards integrating multiple sensor modalities for realizing multi-parameter sensing. For example, at present, almost all the wearable chemical sensors rely on a single transduction mechanism – electrochemical,51, 162 electrical,37, 163 or optical.106,110 However, if one desires to develop multi-chemical sensors, one will have to combine several transducers on the same platform. This is necessary, since a common 10 ACS Paragon Plus Environment

Page 11 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

transduction mechanism may not be suitable for all target analytes. Combining multiple sensing transducers can also help in reducing false positives. For example, two mutually exclusive transducers for detecting the same analyte have been shown to predict the concentration more accurately as compared to single transducers.164-165 One should not limit to only combining multiple chemical sensors on a single wearable platform. In order to obtain comprehensive information about a wearer’s well-being, one must simultaneously monitor chemical biomarkers along with physical parameters (e.g., heart rate, respiration rate, or skin temperature). Figure 3 shows representative examples of recently developed multi-analyte wearable chemical sensors. In addition to the above mentioned difficulties faced by the sensors, one must also consider the challenges associated with the manner in which the data generated by the sensor is displayed to the user. Conventionally, display unit, for example, an LCD screen, could be integrated with the sensor. However, this makes the sensor quite bulky. Most LCD screens are rigid leading to poor bio-integration. Recent advances in the field of flexible display units could resolve this issue165,166 While such flexible displays can address the issue of bio-integration, attention should be given also to challenges associated with device size. It is imperative to have a sufficiently large display unit so that the user can easily read the information. One way to address this issue is by integrating the sensor output with other electronic device, such as a Smartphone/Smartwatch. This would obviate the need for including a separate display unit onto the wearable sensor, allowing dramatic miniaturization of the wearable sensor system. 3. Powering Wearable Sensors As the demand for wearable sensors grows, so too does the demand for relevant power sources. Wearable sensors are increasingly becoming “energy-hungry” in order to meet the increasing demands of detecting multiple parameters simultaneously, performing complex data analysis, communicating with other sensors, devices and data transmission. The scientific community that has interest in solving this issue has broadly focused on three aspects – develop low-power energy efficient devices,167-169 compact, energy dense wearable power sources170-172 and adaptive algorithms for intelligent, low-power consuming electronics.168, 173-174 Advances in the field of wearable energy devices have not been able to cope with the speed at which wearable sensor technology has progressed. Limitation caused by inefficient wearable power sources is a common roadblock for effective adaptation of wearable sensors. It is thus imperative to develop wearable power sources that are in the vicinity of the target wearable electronic device in order to obviate the need for long wires and ease of complete device integration with the body. In this regard, several avenues, such as wearable batteries,175-177 supercapacitors,171-172, 178 solar cells,179180 biofuel cells,181-182 thermoelectric,183-184 and piezoelectric/triboelectric,185-187 have been explored by researchers to realize wearable power devices (Figure 4). However, as discussed in the following sub-sections, each of these options has its own advantages and disadvantages. The best available energy harvesting option is often dictated by the way the sensor will be used or worn. While batteries remain the most common power sources for wearable devices, alternative energy-harvesting methods – that obviate the need to change or recharge a battery – have 11 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 12 of 46

received considerable recent attention. Energy harvested from ambient light, body motion, sweat, heat, motion or friction could thus be soon used as attractive alternative to batteries to power wearable chemical sensors. Researchers are now looking into developing energy devices that exploit multiple sources for energy generation.170,188 Such multi-source adaptive energy devices can switch between different fuel sources depending on the fuel supply in order to address the issue of continuous supply of constant power to the electronics. One can dramatically reduce the energy demand of wearable devices by modulating the sampling frequency depending on the physiological and the environmental scenario of the wearer. Such adaptive and compressive sampling can offer significant energy saving. The goal is to tailor the sampling rate of the sensors for maintaining an acceptable analytical performance while greatly decreasing the energy consumption. For example, intelligent adaptive algorithms can enable the wearable device to either switch OFF or reduce the sampling frequency when the wearer’s physiological status is dormant; alternately, these algorithms may increasing the sampling frequency during dynamic physiological state. Such energy management will allow the device to save significant levels of energy and thus prolong the power source’s life-span dramatically. Several teams are now working on such adaptive algorithms for next generation low-power wearable devices.189 However, it is imperative that the need for dynamic sampling, in order to reduce power consumption, does not compromise the quality of the information provided to the user.190 For example, under-sampling by wearable health sensors can have deleterious impact on the wearer’s well-being. The following sections will discuss major wearable energy systems developed and point out some of the issues that hinder them from meeting the requirements of wearable sensors. 3.1 Wearable Batteries 3.1.1 Challenges. Batteries are one of the most mature energy systems and hence have been widely explored the most for wearable applications.175-176 Among various battery systems, lithium-ion batteries are most attractive since they possess long cycle life, impressive shelf life, low self-discharge rate, rapid charge and discharge capability, and high energy efficiency.191 However, most conventional batteries are bulky, and their weight is often heavier than the device that is supposed to power. Furthermore, these conventional batteries are fabricated using rigid, nonconformal materials. Shrinking the battery size and making it lighter and body-compliant is quite different from miniaturizing sensor components, since they follow different scaling laws. With reducing size, the net energy stored in the battery also reduces, thus limiting its long term use. Reducing the battery size also causes slow charging and limited charging-discharging cycles. However, in case of wearables, the users would like to have a power source that charges very fast and has long lifetime. Furthermore, lithium-ion batteries rely on highly toxic materials that can cause serious harm.192-194. Couple this with the battery’s susceptibility to explosion in case of thermal runaway or mechanical damage.193-194 Acknowledging these limitations, researchers 12 ACS Paragon Plus Environment

Page 13 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

have focused on developing alkaline rechargeable batteries in wearable formats since these are relatively benign as compared to lithium ion batteries.176, 195-196 Yet, these face similar problems as their lithium-ion counterparts, namely, low charging rate, and poor life span. Additionally, though these rely on alkaline electrolytes that are relatively safer than electrolytes used in lithium-ion batteries, these electrolytes are quite caustic (high pH), and thus direct contact due to damaging of the battery can lead skin burns. 3.1.2

Solutions

Researchers are attempting to address the issue related to batteries’ bulkiness and rigidity by developing flexible176, 197 and stretchable175, 198 batteries on various paper,199-200 textile197 and elastomeric175, 198 substrates (Figure 4A). While this represents a good start, much needs to be done since the performance of these thin-film, solid-state flexible/stretchable batteries cannot match that of the conventional, state-of-the-art battery system. Advances in the field of materials can help in developing innovative solutions to this issue. For example, Rogers’ group recently combined state-of-the-art rigid battery components on elastomeric substrates to demonstrate a highly stretchable battery.175 Similar strategies could be explored where the best in the field of batteries and stretchable electronics is seamlessly combined to obtain body-compliant battery systems that perform similar to their conventional rigid counterparts. Researchers demonstrated recently the development of ultra-fast recharging batteries.201 This is a crucial advancement that can have immense impact in the wearables field that mandate fast recharging. Leveraging thermoresponsive polymers, Bao’s group demonstrated the development of protective coatings onto Li-ion batteries that turn-off the battery in the case of over-heating202 (Figure 4B). This can lead to developing safer wearable batteries. It is also widely known that performance of batteries dwindles below freezing temperatures. However, sub-zero temperatures are quite common for wearable applications. Wang et al, have attempted to address this issue by developing batteries that self-heat under such conditions.203 These results can help in developing wearable batteries that perform even in freezing conditions. Several researchers are also working on developing high energy density batteries that take advantage of 3D patterning204 or nanoscale materials. Since the battery size cannot be increased in wearable applications, energy harvested from the surrounding environment may be required. 3.2 Wearable Supercapacitors 3.2.1

Challenges

Supercapacitors have gained a considerable recent attention as promising alternatives to batteries for wearable applications owing to their fast charge/discharge capacity, long cycle life and safety.42, 205-206 Such energy storage devices are required for storing energy that can be provided to the desired electronics when required. Supercapacitors can thus play a crucial role in wearable applications wherein constant supply of energy is always a challenge. Wearable supercapacitors can be integrated with energy harvesting devices to store the scavenged energy.186 This stored energy can then be utilized to power wearable sensors. Unfortunately, today’s supercapacitors 13 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 14 of 46

face several challenges that must be resolved.207-208 For example, a major roadblock for researchers lies in the development of supercapacitors with high gravimetric and volumetric performances as well as a long cycle life to satiate the daunting needs of wearable electronics. Multiple factors, such as electrode materials, binder, additives, current collector, separator and electrolyte as well as packaging, collectively affect the volumetric performance of supercapacitors. Resilience towards mechanical deformation induced degradation of performance is another challenge that must be considered.209-211 Thus it is mandatory that researchers give importance to these parameters to develop new generation of powerful wearable supercapacitors. Supercapacitors also have the issue of high equivalent series resistance, low energy, and high rate of self-discharge, leakage-current and cost. 3.2.2

Solutions

Advances in the field of materials science have the ability to address the issues marring the field of supercapacitors. In particular, carbon-based nanomaterials have attracted the highest attention due to specific surface area, high electrical conductivity and excellent chemical and thermal stability.207, 210, 212 Plethora of research has been conducted to improve the properties of carbonbased supercapacitors that include the synergy of transition metal,178, 186 metal oxides,213-215 polymers,211, 216 hetero-atoms,212, 217 or ionic liquids.218 For instance, graphene–metallic supercapacitor yarns could be used to integrate with wearable sensors (Figure 4C). Researchers have also recently demonstrated the viability of MoS2 towards high-performance supercapacitors.219 In addition to the materials, one can enhance the energy density by designing all-solid-state asymmetric supercapacitors by adjoining varied positive and negative electrode materials with well-separated potential windows to obtain a high operation voltage. Typically, this is achieved by utilizing carbon nanomaterials as Faradic electrodes (energy source) and a suitable carbon material serving as the capacitance electrode (power source). Asymmetric supercapacitors can provide a high operation voltage and hence significantly augment the device energy density. Researchers have also explored combining the supercapacitors in various series and/or parallel combinations to obtain desired energy requirements. Additionally, micro-/nanosupercapacitors are being considered since they offer higher performance than conventional supercapacitors due to their fast responses to ions and electrons.42, 195, 215 3.3 Wearable solar cells 3.3.1 Challenges Light energy is currently considered the most common source of harvestable energy. Although significant advances have been made in the field of photovoltaics, major efforts are required for adapting it as a possible energy source for wearable applications. Firstly, solar energy is not a dense source of energy. Thus, a large surface area of solar panel is required to acquire suitable energy levels for continuous powering of wearable devices. Furthermore, solar cells have highest energy conversion efficiency for sunlight that is incident normal to its surface. Considering the three-dimensional surface of the human body, only a negligible fraction of sunlight falls normal 14 ACS Paragon Plus Environment

Page 15 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

to it. Also, the location at which the sunlight is normal to the skin surface will change depending on the relative motion between the sun and the body. Solar energy conversion also drops significantly in cloudy weather conditions. In addition, more and more human activity is being conducted indoors which minimizes the sun exposure. Furthermore, the solar cell field has several technological challenges. Fabricating state-of-the-art defect-free silicon solar cells is expensive.220 Several solar cells employ toxic elements (e.g. As, Cd) and potential leaching of these metals can be harmful for the human body. In view of these practical challenges, wearable solar cells, though attractive, have limited scope as a viable energy harvesting source for powering on-body sensors. 3.3.2

Solutions

Improving the conversion efficiency is currently the hot topic in solar cell research.221-223 Researchers are exploring new materials that and fabrication techniques that have pushed the conversion efficiency to almost 30%.224 Researchers can look up these developments for developing highly efficient wearable solar cells. Perovskites have recently gained tremendous attention in solar cell field since they show the promise of greatly reducing the cost solar cell fabrication.90, 180, 223, 225 New highly efficient and sensitive dye solar cells could be used to generate power indoor from indirect lighting. Such new materials will be a boon for developing inexpensive wearable solar cells. Similar to batteries, researchers are also making efforts to make flexible197, 226-227 or stretchable74, 179 solar cells that have the potential for wearable applications.179-180, 227 More attention in this direction will have major impact in wearable solar cells field (Figure 4D). 3.4 Wearable biofuel cells 3.4.1 Challenges Biofuel cells that harvest biochemical energy using biological components represent an attractive “green” alternative for various wearable and implantable applications.41, 228-229 Biofluids, such as sweat, tears, interstitial fluid and blood, are rich with metabolites that can be exploited as fuels by wearable biofuel cells to generate usable electrical energy. Moreover, biofuel cells act as selfpowered sensors and hence these systems mandate lower energy requirements as compared to conventional chemical sensors.230-231 This is attractive for wearable applications where energy supply is usually a critical challenge. Although, these attributes sound striking, today’s wearable biofuel cells face several daunting challenges that hamper their use as viable energy sources for various wearable applications.228 To begin with, enzymes that convert the fuels into energy are quite labile and lose their catalytic properties in presence of harsh conditions that may be encountered in wearable electronics, e.g. varying temperature, humidity, or presence of certain chemical species. The operational lifespan of the wearable biofuel cells is also short compared to the energy demands of the wearable electronics. In addition, continuous reproducible flow of high concentration of biofuel to the wearable biofuel cells is not possible, since the flow of these 15 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 16 of 46

biofuels is regulated by the human physiology. Thus, continuous generation of constant power is quite challenging. Also, the power generated by these devices is low with the output voltage changing gradually with time. Furthermore, wearable biofuel cells must possess stretchability to endure mechanical deformations common for wearables applications. Developing body compliant stretchable biofuel cells which protect the enzymes and other chemical reagents from degrading/leaching under changing conditions is certainly a challenge. A concoction of these challenges currently impedes the utilization of wearable biofuel cells to directly power electronic devices. 3.4.2

Solutions

By properly addressing the challenges facing wearable biofuel cells, these devices could become a viable energy source for on-body applications. A handful of researchers are attempting to address the issue involved in developing soft, stretchable biofuel cells by combining advances in materials science. For example, our group recently demonstrated a highly stretchable glucose biofuel cell that could be repeatedly stretched by 300% without much effect on its power generation ability77 (Figure 4E). Similarly, Ogawa et al demonstrated a stretchable textile-based biofuel cell that could be repeatedly stretched by 50% with the small impact on the power output (20-30% loss).232 Similar efforts must be made to develop body-compliant biofuel cells. The problem of long-term stability of wearable biofuel cells under diverse conditions could be addressed by incorporating enzyme stabilizing agents or nano/microsized hybrid materials233-235 and by providing biocompatible microenvironments to the immobilized enzyme. Researchers could also look into developing multi-fuel biofuel cells, complete oxidation of fuels236 and rechargeable biofuel cells237-238 to address the issue of continuous supply of energy. At the same time, researchers should leverage nanomaterials to further enhance the power conversion efficiency of the biofuel cells.239-240 4. Communication: Challenges and Possible Solutions Similar to any disruptive technology, the field of wearable sensors is also expected to witness an exponential boom in its demand. As the markets warm up towards wearable sensors, the need to develop faster, more compact, multi-functional, smart wearable sensors will only grow with time. One of the most attractive aspects of the wearable sensor field is uninterrupted streaming of information from various sensor nodes to the wearer. Such sensors will also be expected to continuously interact with a nearby computing device (such as a mobile phone) that automatically classifies certain events in order to provide timely intervention (e.g. message to a remote caregiver or alert to the user). Some wearable sensor applications do not require real-time wireless connectivity, and the data can be logged locally on the sensor platform for several days. The connectivity requirements are amplified in scenarios common to residential or commercial setups, where several individuals have multiple wearable sensors, interacting with each other at high rates, thus requiring high density wireless communication (Figure 5). Such conditions mandate by wearable sensors with unprecedented connectivity. 16 ACS Paragon Plus Environment

Page 17 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

To date, Bluetooth low energy (BLE)23-25, 44 and near-field communication (NFC)43, 45, 78, 241 technologies have been explored the most for wearable sensors applications. Researchers, including our group, have exploited BLE and RF technologies for developing wearable chemical sensors for detecting analytes on the skin23-25, 45, in tears40, 241 and saliva44 (Figure 6). While these protocols are suitable for low density data transmission, they fare poorly when it comes to smooth streaming of data within a complex network of high density wearable sensors. At the same time, BLE and NFC have additional limitations. For example, the power requirement for BLE is still quite high which leads to the requirement of large power sources. Also, the BLE enabled devices have a working range of 100 m which limits the distance the sensor can be from the receiving device. On the other hand, NFC-based systems require that the receiver must be in its close proximity. This makes the system cumbersome for wearable applications and also requires human intervention to bring the receiver close to the sensor for data collection, hence weakening the prospect of having autonomous wearable sensors. Considering these challenges, researchers developing wireless technologies have to come up with radical solutions that can handle long-distance data transmission within a high density network of wearable devices at low cost. Researchers could look into 60 GHz technologies that can potentially deliver the desired rates of several tens of megabits per device and also emerging technologies such as Light Fidelity (Li-Fi). Researchers working on wireless communications must also consider that the goal of data transmission is not to just send all the information generated by the sensors to the wearer, as this will overwhelm the user, but to provide only relevant information that can be easily understood by wearers. Also, continuously sending huge chucks of indiscreet data requires a considerable amount of energy which leads to draining of the energy source. Thus, from the perspective of both energy as well as user-friendliness, it is imperative that only the relevant information generated by the sensors is sent to the user. For example, one can reduce the rate of data transfer when the wearer is in physiologically static condition and increase the same during dynamic state. This will enable devices to have increased life-span and at the same time obviate the possibility of overwhelming the user with excessive levels of data which is unnecessary during homeostatic state. Researchers are therefore exploring innovative adaptive algorithms that modulate the rate of data transfer between the sensor and the receiver, depending on the wearer’s health status and the specific activity thus reducing the burden on the wearable power source. 5. Data Analytics and Security: Challenges and Possible Solutions With the widespread market penetration of wearable sensors, developers will have to inevitably grapple with the challenges of big data analytics and data security. As wearable sensors increasingly become an integral part of humans, these devices are expected to generate unprecedented volumes of un-structured, low quality information originating from a wide variety of heterogeneous sources, such as different physical and chemical sensors. The information that wearable sensors collect and report to their wearer is highly individual. As more consumers rely on wearable sensors, they expose themselves to potential security breaches. Data protection has thus become one of the most crucial factors for the operation of mobile and wearable devices. 17 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 46

Directly sending huge amounts of this unprocessed sensor data will only overwhelm and confuse the user, thus leading to underuse of the wearable device. Providing the most pertinent and relevant analytical information in an easy-to-understand manner is thus essential for widespread adoption of wearable sensor technology. This involves intelligent big data mining to unearth relevant information before presenting it to the user. However, present data mining algorithms will not be able to handle the huge volumes of data that wearable sensor networks are expected to generate.11, 242 Researchers are making efforts towards developing effective strategies to address these issues. For example, data miners are working on new algorithms for data cleaning and filtering243 and expanding data mining protocols for handling heterogeneous information.244 Wearable sensors should be able to provide valuable information at high data rates. This implies that wearable sensors must possess powerful data storage and processing ability. It is quite difficult to achieve the required data storage and processing capabilities directly within a compact wearable device. Data scientists are thus exploring the utility of cloud computing for data storage and processing.245 This obviates the need to incorporate electronics required for saving and analyzing raw data generated by the wearable sensors and thus helps in keeping the device size small. With the majority of the data expected to be stored and processed remotely, concerns about data security and user privacy becomes critical.246 Securing data from hackers is especially true for wearable devices that have applications in the personalized healthcare and defense domains, where leaking of sensitive information can have deleterious effects. Major efforts should thus be devoted for developing data security algorithms aimed at staying one step ahead of professional hackers. Cryptographers are thus working extensively to protect the big data generated by wearable devices by developing innovative cryptologic algorithms.247-249 6. Conclusions and Future Prospects Significant progress has been made in recent years in the field of wearable chemical sensors. Such devices are poised to grow very rapidly over the next decade. Yet, the field of wearable chemical sensors has many challenges to address and technological gaps to fill before realizing its full potential. Addressing these challenges will accelerate the commercial viability of wearable chemical sensors that are low-power and easily integrated with the human body, and provide valuable information in a user-friendly and secure manner to the wearer in a continuous fashion. Several of the challenges facing researchers in the field of wearable chemical sensors can only be solved by innovative cross-disciplinary research, involving researchers not only from standard STEM fields but also from Humanities. Such cross-disciplinary efforts will lead to technologically advanced wearable devices that a wide variety of consumers will be excited to use in their routine daily lives. For example, materials scientists should work on developing novel materials that will enable the transformation of conventional chemical sensors into wearable formats. Similarly, researchers working in the energy field should focus on developing wearable and biocompatible power sources that have high energy density and long life, as well as 18 ACS Paragon Plus Environment

Page 19 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

incorporating multi-source energy harvesting systems. At the same time, engineers involved in developing wireless communication systems should develop devices that will allow high density of wearable electronics to interact uninterruptedly with high bit rates. With greater market penetration, wearable sensors are bound to generate huge volumes of personal data and thus data security and user privacy are a matter of major concern. Thus, cryptologists must work on next generation algorithms that will secure the data generated by the wearable sensors. Besides solving the issues faced by the various above mentioned sectors associated with wearable chemical sensors, one must also work on the seamless integration of these sub-systems. Recent studies have led to a remarkable integration of wearable chemical sensor systems.29-30 Such integration requires ingenious systems engineering skills since the roadblocks faced by wearable sensors domain are unique, and also because all the sub-systems are deeply interconnected with each other. Challenges for integration arise due to different fabrication processes for various physical components of the whole system. Difference in packaging of the sub-components also leads to ineffective device integration. For example, the chemical sensor must be exposed to the biofluid, while the supporting electronics must be completely sealed from any exposure to moisture. The interface between different sensor components is usually where the entire system is most susceptible to fail. Flawless integration of all these sub-systems is thus extremely critical for the development of wearable chemical sensors. In addition to the need for engineers and scientists to work together, the field of wearable sensors also requires intimate coordination and collaboration with medical practitioners. Wearable sensors are expected to generate personal health data that was impossible to obtain earlier. Such health monitoring thus requires close collaboration with physicians to correctly interpret the data. It is clear that the wearable chemical sensor field offers exciting collaborative opportunities and that the commercial success of this rapidly growing field will ultimately rely on the abilities of the researchers to continue to innovate and collaborate to address the existing challenges faced by wearable chemical sensors.

FIGURES

19 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 1. Current status and challenges in wearable chemical sensors.


Page 20 of 46

Page 21 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

.

Figure 2. Possible solutions for materials-based challenges. Schematics and images showing: (A) a flexible ethanol gas sensor65, Reprinted (adapted) with permission from Scientific Reports. (B) a stretchable CNT-based electrochemical sensor array77, Reprinted (adapted) with permission from Nano Letters. Copyright 2016, American Chemical Society; (C) a graphene-based electrochemical device with thermoresponsive microneedles for diabetes monitoring and therapy30, Reprinted (adapted) with permission from Nature Nanotechnology. Copyright 2016, Nature Publishing Group. (D) CNT- and elastomer-based contact lens41, Reprinted (adapted) with permission from Electrochimica Acta. Copyright 2016, Elsevier; (E) a self-healing printed electrochemical sensor85, Reprinted (adapted) with permission from Advanced Electronic Materials. Copyright 2015, John Wiley and Sons; (F) transient electronics87, Reprinted (adapted) with permission from Nature. Copyright 2016, Nature Publishing Group; and (G) nanowiresbased transparent transistors91. Reprinted (adapted) with permission from Nature Nanotechnology. Copyright 2007, Nature Publishing Group.


ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 22 of 46

Figure 3. Solutions for multi-parameter wearable sensing. Images of (A) a wearable electronic nose38, Reprinted (adapted) with permission from Sensors; (B) a textile-based potentiometric sensor for sodium and potassium14, Reprinted (adapted) with permission from Advanced Healthcare Materials. Copyright 2016, John Wiley and Sons, and (C) fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis.29 Reprinted (adapted) with permission from Nature. Copyright 2016, Nature Publishing Group.


Page 23 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

Figure 4. Solutions for power source-based challenges. Images and schematics illustrating (A) stretchable batteries175, Reprinted (adapted) with permission from Nature Communications. Copyright 2013, Nature Publishing Group; (B) a reversible thermoresponsive battery202, Reprinted (adapted) with permission from Nature Energy. Copyright 2016, Nature Publishing Group. (C) wearable yarn supercapacitors178, Reprinted (adapted) with permission from Nature Communications. Copyright 2015, Nature Publishing Group; (D) bendable perovskite solar cells180, Reprinted (adapted) with permission from Energy & Environmental Science. Copyright 2015, Royal Society of Chemistry. (E) highly stretchable biofuel cells77, Reprinted (adapted) with permission from Nano Letters. Copyright 2016, American Chemical Society; and (F) a single platform containing a piezoelectric nanogenerator and photovoltaic device for multisource energy harvesting188. Reprinted (adapted) with permission from Nano Energy. Copyright 2015, Elsevier.


ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 5. Scheme showing a typical multi-nodal wireless network for wearable sensors.


Page 24 of 46

Page 25 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

Figure 6. Solutions for wireless communications. Images showing a BLE-based (A) mouthguard sensor for uric acid,44 Reprinted (adapted) with permission from Biosensors and Bioelectronics. Copyright 2015, Elsevier; (B) sweat monitor24 Reprinted (adapted) with permission from Sensors and Actuators B: Chemical. Copyright 2016, Elsevier, and (C) wearable optical sensor25. Reprinted (adapted) with permission from Sensors and Actuators B: Chemical. Copyright 2016, Elsevier. Images illustrating a RF-based (D) contact lens-based glucose 241 sensor , Reprinted (adapted) with permission from Nature Biotechnology. Copyright 2014, Nature Publishing Group; (E) electrochemical analyzer tag for sensing78, Reprinted (adapted) with permission from Scientific Reports; (F) bandage-based uric acid sensor for monitoring wound healing45. Reprinted (adapted) with permission from Electrochemistry Communications. Copyright 2015, Elsevier; and (G) tooth tattoo for bacteria monitoring.43 Reprinted (adapted) with permission from Nature Communications. Copyright 2012, Nature Publishing Group.


ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

TOC

References 1. Atzori, L.; Iera, A.; Morabito, G.; Nitti, M. The Social Internet of Things (SIoT) – When social networks meet the Internet of Things: Concept, architecture and network characterization. Computer Networks. 2012, 56, 3594-3608. 2. Gómez, J.; Huete, J. F.; Hoyos, O.; Perez, L.; Grigori, D. Interaction System based on Internet of Things as Support for Education. Procedia Computer Science. 2013, 21, 132-139. 3. Darianian, M.; Michael, M. P. In Smart Home Mobile RFID-Based Internet-of-Things Systems and Services, Advanced Computer Theory and Engineering, 2008. ICACTE '08. International Conference on, 20-22 Dec. 2008; pp 116-120. 4. Chen, C.; Tsow, F.; Xian, X.; Forzani, E.; Tao, N.; Tsui, R. A Wearable Sensing System for Assessment of Exposures to Environmental Volatile Organic Compounds. In Mobile Health Technologies: Methods and Protocols, Rasooly, A.; Herold, E. K., Eds. Springer New York: New York, NY, 2015; pp 201-211. 5. Hart, J. K.; Martinez, K. Toward an environmental Internet of Things. Earth and Space Science. 2015, 2, 194-200. 6. Lorincz, K.; Malan, D. J.; Fulford-Jones, T. R. F.; Nawoj, A.; Clavel, A.; Shnayder, V.; Mainland, G.; Welsh, M.; Moulton, S. Sensor networks for emergency response: challenges and opportunities. Pervasive Computing, IEEE. 2004, 3, 16-23. 7. Bui, N.; Zorzi, M. Health care applications: a solution based on the internet of things. In Proceedings of the 4th International Symposium on Applied Sciences in Biomedical and Communication Technologies, ACM: Barcelona, Spain, 2011; pp 1-5. 26 ACS Paragon Plus Environment

Page 26 of 46

Page 27 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

8. Pang, Z.; Zheng, L.; Tian, J.; Kao-Walter, S.; Dubrova, E.; Chen, Q. Design of a terminal solution for integration of in-home health care devices and services towards the Internet-ofThings. Enterprise Information Systems. 2015, 9, 86-116. 9. Drew, B. J.; Califf, R. M.; Funk, M.; Kaufman, E. S.; Krucoff, M. W.; Laks, M. M.; Macfarlane, P. W.; Sommargren, C.; Swiryn, S.; Van Hare, G. F. Practice Standards for Electrocardiographic Monitoring in Hospital Settings. Circulation. 2004, 110, 2721-2746. 10. Domingo, M. C. An overview of the Internet of Things for people with disabilities. Journal of Network and Computer Applications. 2012, 35, 584-596. 11. Andreu-Perez, J.; Leff, D. R.; Ip, H. M. D.; Yang, G. Z. From Wearable Sensors to Smart Implants - Toward Pervasive and Personalized Healthcare. IEEE Transactions on Biomedical Engineering. 2015, 62, 2750-2762. 12. Zhu, Z.; Liu, T.; Li, G.; Li, T.; Inoue, Y. Wearable Sensor Systems for Infants. Sensors. 2015, 15, 3721-3749. 13. Bandodkar, A. J.; Wang, J. Non-invasive wearable electrochemical sensors: a review. Trends Biotechnol. 2014, 32, 363-371. 14. Parrilla, M.; Cánovas, R.; Jeerapan, I.; Andrade, F. J.; Wang, J. A Textile-Based Stretchable Multi-Ion Potentiometric Sensor. Adv. Healthcare Mater. 2016, DOI: 10.1002/adhm.201600092. 15. Trung, T. Q.; Lee, N.-E. Flexible and Stretchable Physical Sensor Integrated Platforms for Wearable Human-Activity Monitoring and Personal Healthcare. Adv. Mater. 2016, DOI: 10.1002/adma.201504244. 16. Steinhubl, S. R.; Muse, E. D.; Topol, E. J. The emerging field of mobile health. Science Translational Medicine. 2015, 7, 283rv3-283rv3. 17. Trung, T. Q.; Ramasundaram, S.; Hwang, B.-U.; Lee, N.-E. An All-Elastomeric Transparent and Stretchable Temperature Sensor for Body-Attachable Wearable Electronics. Adv. Mater. 2016, 28, 502-509. 18. Kim, K. K.; Hong, S.; Cho, H. M.; Lee, J.; Suh, Y. D.; Ham, J.; Ko, S. H. Highly sensitive and stretchable multidimensional strain sensor with prestrained anisotropic Metal Nanowire Percolation Networks. Nano Lett. 2015, 15, 5240-5247. 19. Son, D.; Lee, J.; Qiao, S.; Ghaffari, R.; Kim, J.; Lee, J. E.; Song, C.; Kim, S. J.; Lee, D. J.; Jun, S. W.; Yang, S.; Park, M.; Shin, J.; Do, K.; Lee, M.; Kang, K.; Hwang, C. S.; Lu, N.; Hyeon, T.; Kim, D.-H. Multifunctional wearable devices for diagnosis and therapy of movement disorders. Nat. Nanotechnol. 2014, 9, 397-404. 20. Yamada, T.; Hayamizu, Y.; Yamamoto, Y.; Yomogida, Y.; Izadi-Najafabadi, A.; Futaba, D. N.; Hata, K. A stretchable carbon nanotube strain sensor for human-motion detection. Nat. Nanotechnol. 2011, 6, 296-301. 27 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

21. Takamatsu, S.; Lonjaret, T.; Crisp, D.; Badier, J.-M.; Malliaras, G. G.; Ismailova, E. Direct patterning of organic conductors on knitted textiles for long-term electrocardiography. Sci. Rep. 2015, 5, 15003. 22. Jeong, G. S.; Baek, D.-H.; Jung, H. C.; Song, J. H.; Moon, J. H.; Hong, S. W.; Kim, I. Y.; Lee, S.-H. Solderable and electroplatable flexible electronic circuit on a porous stretchable elastomer. Nat. Commun. 2012, 3, 977. 23. Bandodkar, A. J.; Molinnus, D.; Mirza, O.; Guinovart, T.; Windmiller, J. R.; ValdesRamirez, G.; Andrade, F. J.; Schoning, M. J.; Wang, J. Epidermal tattoo potentiometric sodium sensors with wireless signal transduction for continuous non-invasive sweat monitoring. Biosens. Bioelectron. 2014, 54, 603-609. 24. Liu, G.; Ho, C.; Slappey, N.; Zhou, Z.; Snelgrove, S. E.; Brown, M.; Grabinski, A.; Guo, X.; Chen, Y.; Miller, K.; Edwards, J.; Kaya, T. A wearable conductivity sensor for wireless realtime sweat monitoring. Sens. Actuators, B. 2016, 227, 35-42. 25. Caldara, M.; Colleoni, C.; Guido, E.; Re, V.; Rosace, G. Optical monitoring of sweat pH by a textile fabric wearable sensor based on covalently bonded litmus-3glycidoxypropyltrimethoxysilane coating. Sens. Actuators, B. 2016, 222, 213-220. 26. Parrilla, M.; Ferré, J.; Guinovart, T.; Andrade, F. J. Wearable Potentiometric Sensors Based on Commercial Carbon Fibres for Monitoring Sodium in Sweat. Electroanalysis. 2016, DOI: 10.1002/elan.201600070. 27. Jia, W.; Bandodkar, A. J.; Valdés-Ramírez, G.; Windmiller, J. R.; Yang, Z.; Ramírez, J.; Chan, G.; Wang, J. Electrochemical Tattoo Biosensors for Real-Time Noninvasive Lactate Monitoring in Human Perspiration. Anal. Chem. 2013, 85, 6553-6560. 28. Kim, J.; Valdes-Ramirez, G.; Bandodkar, A. J.; Jia, W.; Martinez, A. G.; Ramirez, J.; Mercier, P.; Wang, J. Non-invasive mouthguard biosensor for continuous salivary monitoring of metabolites. Analyst. 2014, 139, 1632-1636. 29. Gao, W.; Emaminejad, S.; Nyein, H. Y. Y.; Challa, S.; Chen, K.; Peck, A.; Fahad, H. M.; Ota, H.; Shiraki, H.; Kiriya, D.; Lien, D.-H.; Brooks, G. A.; Davis, R. W.; Javey, A. Fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis. Nature. 2016, 529, 509-514. 30. Lee, H.; Choi, T. K.; Lee, Y. B.; Cho, H. R.; Ghaffari, R.; Wang, L.; Choi, H. J.; Chung, T. D.; Lu, N.; Hyeon, T.; Choi, S. H.; Kim, D.-H. A graphene-based electrochemical device with thermoresponsive microneedles for diabetes monitoring and therapy. Nat. Nanotechnol. 2016, DOI:10.1038/nnano.2016.38. 31. Panneer Selvam, A.; Muthukumar, S.; Kamakoti, V.; Prasad, S. A wearable biochemical sensor for monitoring alcohol consumption lifestyle through Ethyl glucuronide (EtG) detection in human sweat. Sci. Rep. 2016, 6, 23111.


Page 28 of 46

Page 29 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

32. Khodagholy, D.; Curto, V. F.; Fraser, K. J.; Gurfinkel, M.; Byrne, R.; Diamond, D.; Malliaras, G. G.; Benito-Lopez, F.; Owens, R. M. Organic electrochemical transistor incorporating an ionogel as a solid state electrolyte for lactate sensing. J. Mater. Chem. 2012, 22, 4440-4443. 33. Kim, J.; de Araujoa, W.R.; Samek, I.A.; Bandodkar, A.J. Jia, W.; Brunetti, B.; Paixão, R.L.C.; Wang, J. Wearable tattoo sensor for real-time trace-metal monitoring in human sweat. Electrochemistry Commun., 2015, 51.41-46. 34. Lisak, G.; Arnebrant, T.; Ruzgas, T.; Bobacka, J. Textile-based sampling for potentiometric determination of ions. Anal. Chim. Acta. 2015, 877, 71-79. 35. Seesaard, T.; Lorwongtragool, P.; Kerdcharoen, T. Development of fabric-based chemical gas sensors for use as wearable electronic noses. Sensors. 2015, 15, 1885-1902. 36. Ataman, C.; Kinkeldei, T.; Mattana, G.; Vásquez Quintero, A.; Molina-Lopez, F.; Courbat, J.; Cherenack, K.; Briand, D.; Tröster, G.; de Rooij, N. F. A robust platform for textile integrated gas sensors. Sens. Actuators, B. 2013, 177, 1053-1061. 37. Kim, Y. H.; Kim, S. J.; Kim, Y.-J.; Shim, Y.-S.; Kim, S. Y.; Hong, B. H.; Jang, H. W. Self-Activated Transparent All-Graphene Gas Sensor with Endurance to Humidity and Mechanical Bending. ACS Nano. 2015, 9, 10453-10460. 38. Lorwongtragool, P.; Sowade, E.; Watthanawisuth, N.; Baumann, R.; Kerdcharoen, T. A novel wearable electronic nose for healthcare based on flexible printed chemical sensor array. Sensors. 2014, 14, 19700. 39. Yao, H.; Liao, Y.; Lingley, A. R.; Afanasiev, A.; Lähdesmäki, I.; Otis, B. P.; Parviz, B. A. A contact lens with integrated telecommunication circuit and sensors for wireless and continuous tear glucose monitoring. J. Micromech. Microeng. 2012, 22, 075007. 40. Pankratov, D.; González-Arribas, E.; Blum, Z.; Shleev, S. Tear based bioelectronics Electroanalysis, in press. DOI: 10.1002/elan.201501116 41. Reid, R. C.; Jones, S. R.; Hickey, D. P.; Minteer, S. D.; Gale, B. K. Modeling carbon nanotube connectivity and surface activity in a contact lens biofuel cell. Electrochim. Acta. 2016, 203, 30-40. 42. Mak, W. C.; Cheung, K. Y.; Orban, J.; Lee, C.-J.; Turner, A. P. F.; Griffith, M. SurfaceEngineered Contact Lens as an Advanced Theranostic Platform for Modulation and Detection of Viral Infection. ACS Appl. Mater. Interfaces. 2015, 7, 25487-25494. 43. Mannoor, M. S.; Tao, H.; Clayton, J. D.; Sengupta, A.; Kaplan, D. L.; Naik, R. R.; Verma, N.; Omenetto, F. G.; McAlpine, M. C. Graphene-based wireless bacteria detection on tooth enamel. Nat. Commun. 2012, 3, 763.


ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

44. Kim, J.; Imani, S.; de Araujo, W. R.; Warchall, J.; Valdés-Ramírez, G.; Paixão, T. R. L. C.; Mercier, P. P.; Wang, J. Wearable salivary uric acid mouthguard biosensor with integrated wireless electronics. Biosens. Bioelectron. 2015, 74, 1061-1068. 45. Kassal, P.; Kim, J.; Kumar, R.; de Araujo, W. R.; Steinberg, I. M.; Steinberg, M. D.; Wang, J. Smart bandage with wireless connectivity for uric acid biosensing as an indicator of wound status. Electrochem. Commun. 2015, 56, 6-10. 46. Hattori, Y.; Falgout, L.; Lee, W.; Jung, S.-Y.; Poon, E.; Lee, J. W.; Na, I.; Geisler, A.; Sadhwani, D.; Zhang, Y.; Su, Y.; Wang, X.; Liu, Z.; Xia, J.; Cheng, H.; Webb, R. C.; Bonifas, A. P.; Won, P.; Jeong, J.-W.; Jang, K.-I.; Song, Y. M.; Nardone, B.; Nodzenski, M.; Fan, J. A.; Huang, Y.; West, D. P.; Paller, A. S.; Alam, M.; Yeo, W.-H.; Rogers, J. A. Multifunctional SkinLike Electronics for Quantitative, Clinical Monitoring of Cutaneous Wound Healing. Adv. Healthcare Mater. 2014, 3, 1597-1607. 47. Milne, S. D.; Seoudi, I.; Al Hamad, H.; Talal, T. K.; Anoop, A. A.; Allahverdi, N.; Zakaria, Z.; Menzies, R.; Connolly, P. A wearable wound moisture sensor as an indicator for wound dressing change: an observational study of wound moisture and status. Int. Wound J. 2015, DOI: 10.1111/iwj.12521. 48. Zeng, W.; Shu, L.; Li, Q.; Chen, S.; Wang, F.; Tao, X. M. Fiber-based wearable electronics: a review of materials, fabrication, devices, and applications. Adv. Mater. 2014, 26, 5310-36. 49. Diamond, D.; Coyle, S.; Scarmagnani, S.; Hayes, J. Wireless sensor networks and chemo-/biosensing. Chem. Rev. 2008, 108, 652-679. 50. Choi, S.; Lee, H.; Ghaffari, R.; Hyeon, T.; Kim, D. H. Recent Advances in Flexible and Stretchable Bio-Electronic Devices Integrated with Nanomaterials. Adv. Mater. 2016, DOI: 10.1002/adma.201504150. 51. Matzeu, G.; Florea, L.; Diamond, D. Advances in wearable chemical sensor design for monitoring biological fluids. Sens. Actuators, B. 2015, 211, 403-418. 52. Chan, M.; Estève, D.; Fourniols, J.-Y.; Escriba, C.; Campo, E. Smart wearable systems: Current status and future challenges. Artificial Intelligence in Medicine. 2012, 56, 137-156. 53. Attal, F.; Mohammed, S.; Dedabrishvili, M.; Chamroukhi, F.; Oukhellou, L.; Amirat, Y. Physical human activity recognition using wearable sensors. Sensors. 2015, 15, 31314-31338. 54. Bandodkar, A. J.; Jia, W.; Wang, J. Tattoo-based wearable electrochemical devices: a review. Electroanalysis. 2015, 27, 562-572. 55. Corrie, S. R.; Coffey, J. W.; Islam, J.; Markey, K. A.; Kendall, M. A. F. Blood, sweat, and tears: developing clinically relevant protein biosensors for integrated body fluid analysis. Analyst. 2015, 140, 4350-4364.


Page 30 of 46

Page 31 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

56. Stoppa, M.; Chiolerio, A. Wearable electronics and smart textiles: a critical review. Sensors. 2014, 14, 11957-92. 57. Steinberg, M. D.; Kassal, P.; Steinberg, I. M. System architectures in wearable electrochemical sensors. Electroanalysis. 2016, DOI: 10.1002/elan.201600094. 58. Takei, K.; Honda, W.; Harada, S.; Arie, T.; Akita, S. Toward Flexible and Wearable Human-Interactive Health-Monitoring Devices. Adv. Healthcare Mater. 2015, 4, 487-500. 59. Goda, T.; Yamada, E.; Katayama, Y.; Tabata, M.; Matsumoto, A.; Miyahara, Y. Potentiometric responses of ion-selective microelectrode with bovine serum albumin adsorption. Biosens. Bioelectron. 2016, 77, 208-214. 60. Baker, L. B.; Ungaro, C. T.; Barnes, K. A.; Nuccio, R. P.; Reimel, A. J.; Stofan, J. R. Validity and reliability of a field technique for sweat Na+ and K+ analysis during exercise in a hot-humid environment. Physiol. Rep. 2014, 2, DOI: 10.14814/phy2.12007. 61. Musso, J.; Buchmann, W.; Gonnet, F.; Jarroux, N.; Bellon, S.; Frydman, C.; Brunet, D.L.; Daniel, R. Biomarkers probed in saliva by surface plasmon resonance imaging coupled to matrix-assisted laser desorption/ionization mass spectrometry in array format. Anal. Bioanal. Chem. 2014, 407, 1285-1294. 62. Leickly, E.; McDonell, M. G.; Vilardaga, R.; Angelo, F. A.; Lowe, J. M.; McPherson, S.; Srebnik, D.; Roll, J. M.; Ries, R. K. High levels of agreement between clinic-based ethyl glucuronide (EtG) immunoassays and laboratory-based mass spectrometry. Am. J. Drug Alcohol Abuse. 2015, 41, 246-250. 63.

Wang, J. Electrochemical glucose biosensors. Chem. Rev. 2008, 108, 814-825.

64. McAlpine, M. C.; Ahmad, H.; Wang, D.; Heath, J. R. Highly ordered nanowire arrays on plastic substrates for ultrasensitive flexible chemical sensors. Nat Mater. 2007, 6, 379-384. 65. Zheng, Z. Q.; Yao, J. D.; Wang, B.; Yang, G. W. Light-controlling, flexible and transparent ethanol gas sensor based on ZnO nanoparticles for wearable devices. Sci. Rep. 2015, 5, 11070. 66. Rogers, J. A.; Someya, T.; Huang, Y. Materials and Mechanics for Stretchable Electronics. Science. 2010, 327, 1603-1607. 67. Hwang, S.-W.; Lee, C. H.; Cheng, H.; Jeong, J.-W.; Kang, S.-K.; Kim, J.-H.; Shin, J.; Yang, J.; Liu, Z.; Ameer, G. A.; Huang, Y.; Rogers, J. A. Biodegradable Elastomers and Silicon Nanomembranes/Nanoribbons for Stretchable, Transient Electronics, and Biosensors. Nano Lett. 2015, 15, 2801-2808. 68. Jang, K.-I.; Han, S. Y.; Xu, S.; Mathewson, K. E.; Zhang, Y.; Jeong, J.-W.; Kim, G.-T.; Webb, R. C.; Lee, J. W.; Dawidczyk, T. J.; Kim, R. H.; Song, Y. M.; Yeo, W.-H.; Kim, S.; Cheng, H.; Rhee, S. I.; Chung, J.; Kim, B.; Chung, H. U.; Lee, D.; Yang, Y.; Cho, M.; Gaspar, J. G.; Carbonari, R.; Fabiani, M.; Gratton, G.; Huang, Y.; Rogers, J. A. Rugged and breathable 31 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

forms of stretchable electronics with adherent composite substrates for transcutaneous monitoring. Nat. Commun. 2014, 5, DOI:10.1038/ncomms5779. 69. Chung, H.-J.; Sulkin, M. S.; Kim, J.-S.; Goudeseune, C.; Chao, H.-Y.; Song, J. W.; Yang, S. Y.; Hsu, Y.-Y.; Ghaffari, R.; Efimov, I. R.; Rogers, J. A. Stretchable, Multiplexed pH Sensors With Demonstrations on Rabbit and Human Hearts Undergoing Ischemia. Adv. Healthcare Mater. 2014, 3, 59-68. 70. Lee, S.; Reuveny, A.; Reeder, J.; Lee, S.; Jin, H.; Liu, Q.; Yokota, T.; Sekitani, T.; Isoyama, T.; Abe, Y.; Suo, Z.; Someya, T. A transparent bending-insensitive pressure sensor. Nat. Nanotechnol. 2016, DOI:10.1038/nnano.2015.324. 71. Nawrocki, R. A.; Matsuhisa, N.; Yokota, T.; Someya, T. 300-nm Imperceptible, Ultraflexible, and Biocompatible e-Skin Fit with Tactile Sensors and Organic Transistors. Adv. Electron. Mater. 2016, DOI: 10.1002/aelm.201500452. 72. Sekitani, T.; Noguchi, Y.; Hata, K.; Fukushima, T.; Aida, T.; Someya, T. A Rubberlike Stretchable Active Matrix Using Elastic Conductors. Science. 2008, 321, 1468-1472. 73. Chou, H.-H.; Nguyen, A.; Chortos, A.; To, J. W. F.; Lu, C.; Mei, J.; Kurosawa, T.; Bae, W.-G.; Tok, J. B. H.; Bao, Z. A chameleon-inspired stretchable electronic skin with interactive colour changing controlled by tactile sensing. Nat. Commun. 2015, 6, DOI: 10.1038/ncomms9011. 74. Lipomi, D. J.; Tee, B. C. K.; Vosgueritchian, M.; Bao, Z. Stretchable Organic Solar Cells. Adv. Mater. 2011, 23, 1771-1775. 75. Ramuz, M.; Tee, B. C. K.; Tok, J. B. H.; Bao, Z. Transparent, Optical, Pressure-Sensitive Artificial Skin for Large-Area Stretchable Electronics. Adv. Mater. 2012, 24, 3223-3227. 76. Bandodkar, A. J.; Nuñez-Flores, R.; Jia, W.; Wang, J. All-Printed Stretchable Electrochemical Devices. Adv. Mater. 2015, 27, 3060-3065. 77. Bandodkar, A. J.; Jeerapan, I.; You, J.-M.; Nuñez-Flores, R.; Wang, J. Highly Stretchable Fully-Printed CNT-Based Electrochemical Sensors and Biofuel Cells: Combining Intrinsic and Design-Induced Stretchability. Nano Lett. 2016, 16, 721-727. 78. Jung, Y.; Park, H.; Park, J.-A.; Noh, J.; Choi, Y.; Jung, M.; Jung, K.; Pyo, M.; Chen, K.; Javey, A.; Cho, G. Fully printed flexible and disposable wireless cyclic voltammetry tag. Sci. Rep. 2015, 5, 8105. 79. Liu, J.; Yang, C.; Wu, H.; Lin, Z.; Zhang, Z.; Wang, R.; Li, B.; Kang, F.; Shi, L.; Wong, C. P. Future paper based printed circuit boards for green electronics: fabrication and life cycle assessment. Energy Environ. Sci. 2014, 7, 3674-3682. 80. Tybrandt, K.; Vörös, J. Fast and Efficient Fabrication of Intrinsically Stretchable Multilayer Circuit Boards by Wax Pattern Assisted Filtration. Small. 2016, 12, 180-184.


Page 32 of 46

Page 33 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

81. van den Brand, J.; de Kok, M.; Koetse, M.; Cauwe, M.; Verplancke, R.; Bossuyt, F.; Jablonski, M.; Vanfleteren, J. Flexible and stretchable electronics for wearable health devices. Solid-State Electron. 2015, 113, 116-120. 82. Yang, Y.; Zhu, B.; Yin, D.; Wei, J.; Wang, Z.; Xiong, R.; Shi, J.; Liu, Z.; Lei, Q. Flexible self-healing nanocomposites for recoverable motion sensor. Nano Energy. 2015, 17, 1-9. 83. Tee, B. C. K.; Wang, C.; Allen, R.; Bao, Z. An electrically and mechanically self-healing composite with pressure- and flexion-sensitive properties for electronic skin applications. Nat. Nanotechnol. 2012, 7, 825-832. 84. Cordier, P.; Tournilhac, F.; Soulie-Ziakovic, C.; Leibler, L. Self-healing and thermoreversible rubber from supramolecular assembly. Nature. 2008, 451, 977-980. 85. Bandodkar, A. J.; Mohan, V.; López, C. S.; Ramírez, J.; Wang, J. Self-Healing Inks for Autonomous Repair of Printable Electrochemical Devices. Adv. Electron. Mater. 2015, 1, DOI: 10.1002/aelm.201500289. 86. Hwang, S.-W.; Tao, H.; Kim, D.-H.; Cheng, H.; Song, J.-K.; Rill, E.; Brenckle, M. A.; Panilaitis, B.; Won, S. M.; Kim, Y.-S.; Song, Y. M.; Yu, K. J.; Ameen, A.; Li, R.; Su, Y.; Yang, M.; Kaplan, D. L.; Zakin, M. R.; Slepian, M. J.; Huang, Y.; Omenetto, F. G.; Rogers, J. A. A Physically Transient Form of Silicon Electronics. Science. 2012, 337, 1640-1644. 87. Kang, S.-K.; Murphy, R. K. J.; Hwang, S.-W.; Lee, S. M.; Harburg, D. V.; Krueger, N. A.; Shin, J.; Gamble, P.; Cheng, H.; Yu, S.; Liu, Z.; McCall, J. G.; Stephen, M.; Ying, H.; Kim, J.; Park, G.; Webb, R. C.; Lee, C. H.; Chung, S.; Wie, D. S.; Gujar, A. D.; Vemulapalli, B.; Kim, A. H.; Lee, K.-M.; Cheng, J.; Huang, Y.; Lee, S. H.; Braun, P. V.; Ray, W. Z.; Rogers, J. A. Bioresorbable silicon electronic sensors for the brain. Nature. 2016, 530, 71-76. 88. He, Q.; Wu, S.; Gao, S.; Cao, X.; Yin, Z.; Li, H.; Chen, P.; Zhang, H. Transparent, Flexible, All-Reduced Graphene Oxide Thin Film Transistors. ACS Nano. 2011, 5, 5038-5044. 89. Xia, Y.; Sun, K.; Ouyang, J. Solution-Processed Metallic Conducting Polymer Films as Transparent Electrode of Optoelectronic Devices. Adv. Mater. 2012, 24, 2436-2440. 90. Sun, K.; Li, P.; Xia, Y.; Chang, J.; Ouyang, J. Transparent Conductive Oxide-Free Perovskite Solar Cells with PEDOT:PSS as Transparent Electrode. ACS Appl. Mater. Interfaces. 2015, 7, 15314-15320. 91. Ju, S.; Facchetti, A.; Xuan, Y.; Liu, J.; Ishikawa, F.; Ye, P.; Zhou, C.; Marks, T. J.; Janes, D. B. Fabrication of fully transparent nanowire transistors for transparent and flexible electronics. Nat. Nanotechnol. 2007, 2, 378-384. 92. Lin, C.-h.; Chang, S.-J.; Chen, W.-S.; Hsueh, T.-J. Transparent ZnO-nanowire-based device for UV light detection and ethanol gas sensing on c-Si solar cell. RSC Adv. 2016, 6, 11146-11150.


ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

93. Wu, H.; Kong, D.; Ruan, Z.; Hsu, P.-C.; Wang, S.; Yu, Z.; Carney, T. J.; Hu, L.; Fan, S.; Cui, Y. A transparent electrode based on a metal nanotrough network. Nat. Nanotechnol. 2013, 8, 421-425. 94. Yang, T.; Bai, X.; Gao, D.; Wu, L.; Li, B.; Thong, J. T. L.; Qiu, C.-W. Invisible Sensors: Simultaneous Sensing and Camouflaging in Multiphysical Fields. Adv. Mater. 2015, 27, 77527758. 95. Zou, X. U.; Zhen, X. V.; Cheong, J. H.; Bühlmann, P. Calibration-Free Ionophore-Based Ion-Selective Electrodes With a Co(II)/Co(III) Redox Couple-Based Solid Contact. Anal. Chem. 2014, 86, 8687-8692. 96. Cisternas, R.; Kahlert, H.; Scholz, F.; Wulff, H. Direct contact tungsten bronze electrodes for calibration-free potentiometric pH measurements. Electrochem. Commun. 2015, 60, 17-20. 97. Gupta Chatterjee, S.; Chatterjee, S.; Ray, A. K.; Chakraborty, A. K. Graphene–metal oxide nanohybrids for toxic gas sensor: A review. Sens. Actuators, B. 2015, 221, 1170-1181. 98. Wen, Z.; Chen, J.; Yeh, M.-H.; Guo, H.; Li, Z.; Fan, X.; Zhang, T.; Zhu, L.; Wang, Z. L. Blow-driven triboelectric nanogenerator as an active alcohol breath analyzer. Nano Energy. 2015, 16, 38-46. 99. Deng, J.; Ma, J.; Mei, L.; Tang, Y.; Chen, Y.; Lv, T.; Xu, Z.; Wang, T. Porous α-Fe2O3 nanosphere-based H2S sensor with fast response, high selectivity and enhanced sensitivity. J. Mater. Chem. A. 2013, 1, 12400-12403. 100. Chen, C.; Xie, Q.; Yang, D.; Xiao, H.; Fu, Y.; Tan, Y.; Yao, S. Recent advances in electrochemical glucose biosensors: a review. RSC Adv. 2013, 3, 4473-4491. 101. Loyprasert, S.; Hedström, M.; Thavarungkul, P.; Kanatharana, P.; Mattiasson, B. Subattomolar detection of cholera toxin using a label-free capacitive immunosensor. Biosens. Bioelectron. 2010, 25, 1977-1983. 102. Gaylord, S. T.; Dinh, T. L.; Goldman, E. R.; Anderson, G. P.; Ngan, K. C.; Walt, D. R. Ultrasensitive Detection of Ricin Toxin in Multiple Sample Matrixes Using Single-Domain Antibodies. Anal. Chem. 2015, 87, 6570-6577. 103. Bankar, S. B.; Bule, M. V.; Singhal, R. S.; Ananthanarayan, L. Glucose oxidase — An overview. Biotechnol. Adv. 2009, 27, 489-501. 104. Cho, E. S.; Kim, J.; Tejerina, B.; Hermans, T. M.; Jiang, H.; Nakanishi, H.; Yu, M.; Patashinski, A. Z.; Glotzer, S. C.; Stellacci, F.; Grzybowski, B. A. Ultrasensitive detection of toxic cations through changes in the tunnelling current across films of striped nanoparticles. Nat Mater. 2012, 11, 978-985. 105. Lu, R.; Li, W.-W.; Mizaikoff, B.; Katzir, A.; Raichlin, Y.; Sheng, G.-P.; Yu, H.-Q. Highsensitivity infrared attenuated total reflectance sensors for in situ multicomponent detection of volatile organic compounds in water. Nat. Protocols. 2016, 11, 377-386. 34 ACS Paragon Plus Environment

Page 34 of 46

Page 35 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

106. Wang, Y.; La, A.; Ding, Y.; Liu, Y.; Lei, Y. Novel Signal-Amplifying Fluorescent Nanofibers for Naked-Eye-Based Ultrasensitive Detection of Buried Explosives and Explosive Vapors. Adv. Funct. Mater. 2012, 22, 3547-3555. 107.

Wang, J. Electrochemical sensing of explosives. Electroanalysis, 2007, 19, 415-423.

108. Taghdisi, S. M.; Danesh, N. M.; Emrani, A. S.; Ramezani, M.; Abnous, K. A novel electrochemical aptasensor based on single-walled carbon nanotubes, gold electrode and complimentary strand of aptamer for ultrasensitive detection of cocaine. Biosensors and Bioelectron.. 2015, 73, 245-250. 109. Choodum, A.; Parabun, K.; Klawach, N.; Daeid, N. N.; Kanatharana, P.; Wongniramaikul, W. Real time quantitative colourimetric test for methamphetamine detection using digital and mobile phone technology. Forensic Sci. Int. 2014, 235, 8-13. 110. Emrani, A. S.; Danesh, N. M.; Ramezani, M.; Taghdisi, S. M.; Abnous, K. A novel fluorescent aptasensor based on hairpin structure of complementary strand of aptamer and nanoparticles as a signal amplification approach for ultrasensitive detection of cocaine. Biosens. Bioelectron. 2016, 79, 288-293. 111. Takatsuji, Y.; Wakabayashi, R.; Sakakura, T.; Haruyama, T. A “Swingable” straightchain affinity molecule immobilized on a semi-conductor electrode for photo-excited currentbased molecular sensing. Electrochim. Acta. 2015, 180, 202-207. 112. Kadimisetty, K.; Malla, S.; Sardesai, N. P.; Joshi, A. A.; Faria, R. C.; Lee, N. H.; Rusling, J. F. Automated Multiplexed ECL Immunoarrays for cancer biomarker proteins. Anal. Chem. 2015, 87, 4472-4478. 113. 745.

Skladal, P. Advances in electrochemical immunosensors. Electroanalysis, 1997, 9, 737-

114. Mariani, S.; Scarano, S.; Spadavecchia, J.; Minunni, M. A reusable optical biosensor for the ultrasensitive and selective detection of unamplified human genomic DNA with gold nanostars. Biosens. Bioelectron. 2015, 74, 981-988. 115. Lee, S.; Jo, H.; Her, J.; Lee, H. Y.; Ban, C. Ultrasensitive electrochemical detection of engrailed-2 based on homeodomain-specific DNA probe recognition for the diagnosis of prostate cancer. Biosens. Bioelectron. 2015, 66, 32-38. 116. Zribi, B.; Roy, E.; Pallandre, A.; Chebil, S.; Koubaa, M.; Mejri, N.; Gomez, H. M.; Sola, C.; Korri-Youssoufi, H.; Haghiri-Gosnet, A.-M. A microfluidic electrochemical biosensor based on multiwall carbon nanotube/ferrocene for genomic DNA detection of Mycobacterium tuberculosis in clinical isolates. Biomicrofluidics. 2016, 10, 014115. 117. Yin, H.; Zhou, Y.; Yang, Z.; Guo, Y.; Wang, X.; Ai, S.; Zhang, X. Electrochemical immunosensor for N6-methyladenosine RNA modification detection. Sens. Actuators, B. 2015, 221, 1-6.


ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

118. Tran, H. V.; Piro, B.; Reisberg, S.; Huy Nguyen, L.; Dung Nguyen, T.; Duc, H. T.; Pham, M. C. An electrochemical ELISA-like immunosensor for miRNAs detection based on screenprinted gold electrodes modified with reduced graphene oxide and carbon nanotubes. Biosens. Bioelectron. 2014, 62, 25-30. 119. Lee, J.; Park, I.-S.; Kim, H.; Woo, J.-S.; Choi, B.-S.; Min, D.-H. BSA as additive: A simple strategy for practical applications of PNA in bioanalysis. Biosens. Bioelectron. 2015, 69, 167-173. 120. Knoll, W.; Park, H.; Sinner, E.-K.; Yao, D.; Yu, F. Supramolecular interfacial architectures for optical biosensing with surface plasmons. Surf. Sci. 2004, 570, 30-42. 121. Jolly, P.; Tamboli, V.; Harniman, R. L.; Estrela, P.; Allender, C. J.; Bowen, J. L. Aptamer–MIP hybrid receptor for highly sensitive electrochemical detection of prostate specific antigen. Biosens. Bioelectron. 2016, 75, 188-195. 122. Li, J.; Chang, K.-W.; Wang, C.-H.; Yang, C.-H.; Shiesh, S.-C.; Lee, G.-B. On-chip, aptamer-based sandwich assay for detection of glycated hemoglobins via magnetic beads. Biosens. Bioelectron. 2016, 79, 887-893. 123. Liu, R.; Yang, Z.; Guo, Q.; Zhao, J.; Ma, J.; Kang, Q.; Tang, Y.; Xue, Y.; Lou, X.; He, M. Signaling-Probe Displacement Electrochemical Aptamer-based Sensor (SD-EAB) for Detection of Nanomolar Kanamycin A. Electrochim. Acta. 2015, 182, 516-523. 124. Rodríguez-Hernández, J.; Cortajarena, L. A. Selective Biorecognition on Polymer Surfaces: General Issues. In Design of Polymeric Platforms for Selective Biorecognition, Rodríguez-Hernández, J.; Cortajarena, L. A., Eds. Springer International Publishing: Cham, 2015; pp 1-9. 125. Vo-Dinh, T. Nanotechnology in biology and medicine : methods, devices, and applications. CRC Press: Boca Raton, 2007. 126. Zhang, L.; Li, L.; Ma, C.; Ge, S.; Yan, M.; Bian, C. Detection of α-fetoprotein with an ultrasensitive electrochemiluminescence paper device based on green-luminescent nitrogendoped graphene quantum dots. Sens. Actuators, B. 2015, 221, 799-806. 127. Ho, D. H.; Sun, Q.; Kim, S. Y.; Han, J. T.; Kim, D. H.; Cho, J. H. Stretchable and Multimodal All Graphene Electronic Skin. Adv. Mater. 2016, DOI: 10.1002/adma.201505739. 128. Kim, S. Y.; Park, S.; Park, H. W.; Park, D. H.; Jeong, Y.; Kim, D. H. Highly Sensitive and Multimodal All-Carbon Skin Sensors Capable of Simultaneously Detecting Tactile and Biological Stimuli. Adv. Mater. 2015, 27, 4178-4185. 129. Desmet, C.; Blum, L. J.; Marquette, C. A. High-Throughput Multiplexed Competitive Immunoassay for Pollutants Sensing in Water. Anal. Chem. 2012, 84, 10267-10276.


Page 36 of 46

Page 37 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

130. Huang, Y.; Li, F.; Qin, M.; Jiang, L.; Song, Y. A Multi-stopband Photonic-Crystal Microchip for High-Performance Metal-Ion Recognition Based on Fluorescent Detection. Angew. Chem., Int. Ed. 2013, 52, 7296-7299. 131. Yao, C.; Sun, H.; Fu, H.-F.; Tan, Z.-C. Sensitive simultaneous determination of nitrophenol isomers at poly(p-aminobenzene sulfonic acid) film modified graphite electrode. Electrochim. Acta. 2015, 156, 163-170. 132. Huang, J.; Zeng, X.; Sigal, N.; Lund, P. J.; Su, L. F.; Huang, H.; Chien, Y.-h.; Davis, M. M. Detection, phenotyping, and quantification of antigen-specific T cells using a peptide-MHC dodecamer. Proceedings of the National Academy of Sciences. 2016, 113, E1890-E1897. 133. Cosnier, S. Affinity biosensors based on electropolymerized films. Electroanalysis 2005, 17, 1701-1715. 134. Campuzano, S.; Kuralay, F.; Lobo-Castañón, M. J.; Bartošík, M.; Vyavahare, K.; Paleček, E.; Haake, D. A.; Wang, J. Ternary monolayers as DNA recognition interfaces for direct and sensitive electrochemical detection in untreated clinical samples. Biosens. Bioelectron. 2011, 26, 3577-3583. 135. Wang, J.; Chen, S.P.; Lin, M.S. Use of different electropolymerization conditions for controlling the size-exclusion selectivity at polyaniline, polypyrrole and polyphenol films. J. Electroanal. Chem. 1989, 273, 231-242. 136. Scholz, F.; Lange, B. Abrasive stripping voltammetry — an electrochemical solid state spectroscopy of wide applicability. TrAC, Trends Anal. Chem. 1992, 11, 359-367. 137. Bandodkar, A. J.; O'Mahony, A. M.; Ramirez, J.; Samek, I. A.; Anderson, S. M.; Windmiller, J. R.; Wang, J. Solid-state Forensic Finger sensor for integrated sampling and detection of gunshot residue and explosives: towards 'Lab-on-a-finger'. Analyst. 2013, 138, 52885295. 138. de Jong, M.; Sleegers, N.; Kim, J.; Van Durme, F.; Samyn, N.; Wang, J.; De Wael, K. Electrochemical fingerprint of street samples for fast on-site screening of cocaine in seized drug powders. Chem. Sci. 2016, 7, 2364-2370. 139. Iyer, P. V.; Ananthanarayan, L. Enzyme stability and stabilization—Aqueous and nonaqueous environment. Process Biochem. 2008, 43, 1019-1032. 140. Ó’Fágáin, C. Enzyme stabilization—recent experimental progress. Enzyme Microb. Technol. 2003, 33, 137-149. 141. Attri, P.; Venkatesu, P.; Kumar, A. Activity and stability of α-chymotrypsin in biocompatible ionic liquids: enzyme refolding by triethyl ammonium acetate. Phys. Chem. Chem. Phys. 2011, 13, 2788-2796.


ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

142. Wan, L.; Chen, Q.; Liu, J.; Yang, X.; Huang, J.; Li, L.; Guo, X.; Zhang, J.; Wang, K. Programmable Self-Assembly of DNA–Protein Hybrid Hydrogel for Enzyme Encapsulation with Enhanced Biological Stability. Biomacromolecules. 2016, 17, 1543-1550. 143. Wang, J. Nanomaterial‐based amplified transduction of biomolecular. Small, 2005, 1, 1036-1043. 144. Manzanares-Palenzuela, C. L.; Martín-Fernández, B.; Sánchez-Paniagua López, M.; López-Ruiz, B. Electrochemical genosensors as innovative tools for detection of genetically modified organisms. TrAC, Trends Anal. Chem. 2015, 66, 19-31. 145. Yarman, A.; Schulz, C.; Sygmund, C.; Ludwig, R.; Gorton, L.; Wollenberger, U.; Scheller, F. Third generation ATP sensor with enzymatic analyte recycling. Electroanalysis, 2014, 26, 2043-2048. . 146. Koh, C.-Y.; Schaff, U. Y.; Piccini, M. E.; Stanker, L. H.; Cheng, L. W.; Ravichandran, E.; Singh, B.-R.; Sommer, G. J.; Singh, A. K. Centrifugal Microfluidic Platform for Ultrasensitive Detection of Botulinum Toxin. Anal. Chem. 2015, 87, 922-928. 147. Xu, M.; Luo, X.; Davis, J. J. The label free picomolar detection of insulin in blood serum. Biosens. Bioelectron. 2013, 39, 21-25. 148. Zaretski, A. V.; Root, S. E.; Savchenko, A.; Molokanova, E.; Printz, A. D.; Jibril, L.; Arya, G.; Mercola, M.; Lipomi, D. J. Metallic Nanoislands on Graphene as Highly Sensitive Transducers of Mechanical, Biological, and Optical Signals. Nano Lett. 2016, 16, 1375-1380. 149. Li, B.; Zhou, Y.; Wu, W.; Liu, M.; Mei, S.; Zhou, Y.; Jing, T. Highly selective and sensitive determination of dopamine by the novel molecularly imprinted poly(nicotinamide)/CuO nanoparticles modified electrode. Biosens. Bioelectron. 2015, 67, 121128. 150. Xu, J.; Ambrosini, S.; Tamahkar, E.; Rossi, C.; Haupt, K.; Tse Sum Bui, B. Toward a Universal Method for Preparing Molecularly Imprinted Polymer Nanoparticles with Antibodylike Affinity for Proteins. Biomacromolecules. 2016, 17, 345-353. 151. Canfarotta, F.; Poma, A.; Guerreiro, A.; Piletsky, S. Solid-phase synthesis of molecularly imprinted nanoparticles. Nat. Protocols. 2016, 11, 443-455. 152. Wannapob, R.; Kanatharana, P.; Limbut, W.; Numnuam, A.; Asawatreratanakul, P.; Thammakhet, C.; Thavarungkul, P. Affinity sensor using 3-aminophenylboronic acid for bacteria detection. Biosens. Bioelectron. 2010, 26, 357-364. 153. Zhang, J.; Landry, M. P.; Barone, P. W.; Kim, J.-H.; Lin, S.; Ulissi, Z. W.; Lin, D.; Mu, B.; Boghossian, A. A.; Hilmer, A. J.; Rwei, A.; Hinckley, A. C.; Kruss, S.; Shandell, M. A.; Nair, N.; Blake, S.; Sen, F.; Sen, S.; Croy, R. G.; Li, D.; Yum, K.; Ahn, J.-H.; Jin, H.; Heller, D. A.; Essigmann, J. M.; Blankschtein, D.; Strano, M. S. Molecular recognition using corona phase complexes made of synthetic polymers adsorbed on carbon nanotubes. Nat. Nanotechnol. 2013, 8, 959-968.


Page 38 of 46

Page 39 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

154. Hong, L.-R.; Wang, J.-P.; Zhuo, Y.; Chai, Y.-Q.; Zhao, M.; Gui, G.-F.; Yuan, R. A regenerable electrochemiluminescence aptasensor incorporating poly(ethylenimine) and thiosemicarbazide as dual co-reactants for signal amplification. Electrochim. Acta. 2015, 186, 174-181. 155. Goode, J. A.; Rushworth, J. V. H.; Millner, P. A. Biosensor Regeneration: A Review of Common Techniques and Outcomes. Langmuir. 2015, 31, 6267-6276. 156. Miller, P.; Moorman, M.; Manginell, R.; Ashlee, C.; Brener, I.; Wheeler, D.; Narayan, R.; Polsky, R. Towards an Integrated Microneedle Total Analysis Chip for Protein Detection. Electroanalysis. 2016, DOI: 10.1002/elan.201600063. 157. Mirasoli, M.; Guardigli, M.; Michelini, E.; Roda, A. Recent advancements in chemical luminescence-based lab-on-chip and microfluidic platforms for bioanalysis. J. Pharm. Biomed. Anal. 2014, 87, 36-52. 158. Zheng, G.; Patolsky, F.; Cui, Y.; Wang, W. U.; Lieber, C. M. Multiplexed electrical detection of cancer markers with nanowire sensor arrays. Nat. Biotechnol. 2005, 23, 1294-1301. 159. Goodey, A.; Lavigne, J. J.; Savoy, S. M.; Rodriguez, M. D.; Curey, T.; Tsao, A.; Simmons, G.; Wright, J.; Yoo, S.-J.; Sohn, Y.; Anslyn, E. V.; Shear, J. B.; Neikirk, D. P.; McDevitt, J. T. Development of Multianalyte Sensor Arrays Composed of Chemically Derivatized Polymeric Microspheres Localized in Micromachined Cavities. J. Am. Chem. Soc. 2001, 123, 2559-2570. 160. Silzel, J. W.; Cercek, B.; Dodson, C.; Tsay, T.; Obremski, R. J. Mass-sensing, multianalyte microarray immunoassay with imaging detection. Clin. Chem. 1998, 44, 2036-2043. 161. Dickinson, T. A.; White, J.; Kauer, J. S.; Walt, D. R. A chemical-detecting system based on a cross-reactive optical sensor array. Nature. 1996, 382, 697-700. 162. Choudhary, T.; Rajamanickam, G. P.; Dendukuri, D. Woven electrochemical fabricbased test sensors (WEFTS): a new class of multiplexed electrochemical sensors. Lab Chip. 2015, 15, 2064-2072. 163. Mubeen, S.; Lai, M.; Zhang, T.; Lim, J.-H.; Mulchandani, A.; Deshusses, M. A.; Myung, N. V. Hybrid tin oxide-SWNT nanostructures based gas sensor. Electrochim. Acta. 2013, 92, 484-490. 164. Wang, J.; Pumera, M.; Dual conductivity/amperometric detection system for microchip capillary electrophoresis Anal. Chem. 2002, 74, 519-5923. 165. Chen, Y.; Au, J.; Kazlas, P.; Ritenour, A.; Gates, H.; McCreary, M. Electronic paper: Flexible active-matrix electronic ink display. Nature 2003, 424,136. 166. Smith, J.; Bawolek, E.; Lee, Y. K.; Brien, B. O.; Marrs, M.; Howard, E.; Strnad, M.; Christen, J. B.; Goryll, M. Application of flexible flat panel display technology to wearable biomedical devices. Electron. Lett. 2015, 51, 1312-1314.


ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

167. Kassal, P.; Steinberg, I. M.; Steinberg, M. D. Wireless smart tag with potentiometric input for ultra low-power chemical sensing. Sens. Actuators, B. 2013, 184, 254-259. 168. De Marcellis, A.; Depari, A.; Ferri, G.; Flammini, A.; Sisinni, E. A CMOS integrated low-voltage low-power time-controlled interface for chemical resistive sensors. Sens. Actuators, B. 2013, 179, 313-318. 169. Orecchini, G.; Yang, L.; Tentzeris, M. M.; Roselli, L. In Wearable battery-free active paper-printed RFID tag with human-energy scavenger, Microwave Symposium Digest (MTT), 2011 IEEE MTT-S International, 5-10 June 2011; pp 1-1. 170. Zi, Y.; Lin, L.; Wang, J.; Wang, S.; Chen, J.; Fan, X.; Yang, P.-K.; Yi, F.; Wang, Z. L. Triboelectric–Pyroelectric–Piezoelectric Hybrid Cell for High-Efficiency Energy-Harvesting and Self-Powered Sensing. Adv. Mater. 2015, 27, 2340-2347. 171. Dong, L.; Xu, C.; Li, Y.; Wu, C.; Jiang, B.; Yang, Q.; Zhou, E.; Kang, F.; Yang, Q.-H. Simultaneous Production of High-Performance Flexible Textile Electrodes and Fiber Electrodes for Wearable Energy Storage. Adv. Mater. 2016, 28, 1675-1681. 172. Zhang, Y.; Zhao, Y.; Cheng, X.; Weng, W.; Ren, J.; Fang, X.; Jiang, Y.; Chen, P.; Zhang, Z.; Wang, Y.; Peng, H. Realizing both High Energy and High Power Densities by Twisting Three Carbon-Nanotube-Based Hybrid Fibers. Angew. Chem., Int. Ed. 2015, 54, 11177-11182. 173. Kannan, R.; Garg, A. In Adaptive sensor fusion technology for mobile and wearable applications, SENSORS, 2015 IEEE, 1-4 Nov. 2015; pp 1-4. 174. Sarpeshkar, R. Universal Principles for Ultra Low Power and Energy Efficient Design. IEEE Transactions on Circuits and Systems II: Express Briefs. 2012, 59, 193-198. 175. Xu, S.; Zhang, Y.; Cho, J.; Lee, J.; Huang, X.; Jia, L.; Fan, J. A.; Su, Y.; Su, J.; Zhang, H.; Cheng, H.; Lu, B.; Yu, C.; Chuang, C.; Kim, T.-i.; Song, T.; Shigeta, K.; Kang, S.; Dagdeviren, C.; Petrov, I.; Braun, P. V.; Huang, Y.; Paik, U.; Rogers, J. A. Stretchable batteries with self-similar serpentine interconnects and integrated wireless recharging systems. Nat. Commun. 2013, 4, 1543. 176. Berchmans, S.; Bandodkar, A. J.; Jia, W.; Ramirez, J.; Meng, Y. S.; Wang, J. An epidermal alkaline rechargeable Ag-Zn printable tattoo battery for wearable electronics. J. Mater. Chem. A. 2014, 2, 15788-15795. 177. Zhang, Y.; Zhao, Y.; Ren, J.; Weng, W.; Peng, H. Advances in Wearable Fiber-Shaped Lithium-Ion Batteries. Adv. Mater. 2015, DOI: 10.1002/adma.201503891. 178. Liu, L.; Yu, Y.; Yan, C.; Li, K.; Zheng, Z. Wearable energy-dense and power-dense supercapacitor yarns enabled by scalable graphene-metallic textile composite electrodes. Nat. Commun. 2015, 6, DOI: 10.1038/ncomms8260.


Page 40 of 46

Page 41 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

179. O’Connor, T. F.; Zaretski, A. V.; Savagatrup, S.; Printz, A. D.; Wilkes, C. D.; Diaz, M. I.; Sawyer, E. J.; Lipomi, D. J. Wearable organic solar cells with high cyclic bending stability: Materials selection criteria. Sol. Energy Mater. Sol. Cells. 2016, 144, 438-444. 180. Kim, B. J.; Kim, D. H.; Lee, Y.-Y.; Shin, H.-W.; Han, G. S.; Hong, J. S.; Mahmood, K.; Ahn, T. K.; Joo, Y.-C.; Hong, K. S.; Park, N.-G.; Lee, S.; Jung, H. S. Highly efficient and bending durable perovskite solar cells: toward a wearable power source. Energy Environ. Sci. 2015, 8, 916-921. 181. Jia, W.; Valdés-Ramírez, G.; Bandodkar, A. J.; Windmiller, J. R.; Wang, J. Epidermal Biofuel Cells: Energy Harvesting from Human Perspiration. Angew. Chem., Int. Ed. 2013, 52, 7233-7236. 182. Jia, W.; Wang, X.; Imani, S.; Bandodkar, A. J.; Ramirez, J.; Mercier, P. P.; Wang, J. Wearable textile biofuel cells for powering electronics. J. Mater. Chem. A. 2014, 2, 1818418189. 183. Oh, J. Y.; Lee, J. H.; Han, S. W.; Chae, S. S.; Bae, E. J.; Kang, Y. H.; Choi, W. J.; Cho, S. Y.; Lee, J.-O.; Baik, H. K.; Lee, T. I. Chemically exfoliated transition metal dichalcogenide nanosheet-based wearable thermoelectric generators. Energy Environ. Sci. 2016, DOI: 10.1039/C5EE03813H. 184. Lu, Z.; Zhang, H.; Mao, C.; Li, C. M. Silk fabric-based wearable thermoelectric generator for energy harvesting from the human body. Appl. Energy. 2016, 164, 57-63. 185. Jin-Hee, Y.; Hyun-Seung, C.; Seon-Hyung, P.; Seung-Hwan, S.; Kwang-Seok, Y.; Joo Hyeon, L. Effect of garment design on piezoelectricity harvesting from joint movement. Smart Mater. Struct. 2016, 25, 035012. 186. Pu, X.; Li, L.; Liu, M.; Jiang, C.; Du, C.; Zhao, Z.; Hu, W.; Wang, Z. L. Wearable SelfCharging Power Textile Based on Flexible Yarn Supercapacitors and Fabric Nanogenerators. Adv. Mater. 2016, 28, 98-105. 187. Seung, W.; Gupta, M. K.; Lee, K. Y.; Shin, K.-S.; Lee, J.-H.; Kim, T. Y.; Kim, S.; Lin, J.; Kim, J. H.; Kim, S.-W. Nanopatterned Textile-Based Wearable Triboelectric Nanogenerator. ACS Nano. 2015, 9, 3501-3509. 188. Yoon, G. C.; Shin, K.-S.; Gupta, M. K.; Lee, K. Y.; Lee, J.-H.; Wang, Z. L.; Kim, S.-W. High-performance hybrid cell based on an organic photovoltaic device and a direct current piezoelectric nanogenerator. Nano Energy. 2015, 12, 547-555. 189. Mesin, L. A neural algorithm for the non-uniform and adaptive sampling of biomedical data. Comput. Biol. Med. 2016, 71, 223-230. 190. Duch, L. G.; Garcia del Valle, P.; Ganapathy, S.; Burg, A. P.; Atienza Alonso, D. Energy vs. Reliability Trade-offs Exploration in Biomedical Ultra-Low Power Devices. In Design, Automation and Test in Europe Conference (DATE '16), Dresden, Germany, 2016.


ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

191. Cook-Chennault, K. A.; Thambi, N.; Sastry, A. M. Powering MEMS portable devices—a review of non-regenerative and regenerative power supply systems with special emphasis on piezoelectric energy harvesting systems. Smart Mater. Struct. 2008, 17, 043001. 192. Hammami, A.; Raymond, N.; Armand, M. Lithium-ion batteries: Runaway risk of forming toxic compounds. Nature. 2003, 424, 635-636. 193. Zeng, X.; Li, J.; Singh, N. Recycling of Spent Lithium-Ion Battery: A Critical Review. Crit. Rev. Environ. Sci. Technol. 2014, 44, 1129-1165. 194. Lisbona, D.; Snee, T. A review of hazards associated with primary lithium and lithiumion batteries. Process Saf. Environ. Prot. 2011, 89, 434-442. 195. Li, R.; Wang, Y.; Zhou, C.; Wang, C.; Ba, X.; Li, Y.; Huang, X.; Liu, J. CarbonStabilized High-Capacity Ferroferric Oxide Nanorod Array for Flexible Solid-State Alkaline Battery–Supercapacitor Hybrid Device with High Environmental Suitability. Adv. Funct. Mater. 2015, 25, 5384-5394. 196. Lee, D. U.; Fu, J.; Park, M. G.; Liu, H.; Ghorbani Kashkooli, A.; Chen, Z. SelfAssembled NiO/Ni(OH)2 Nanoflakes as Active Material for High-Power and High-Energy Hybrid Rechargeable Battery. Nano Lett. 2016, 16, 1794-1802. 197. Lee, Y.-H.; Kim, J.-S.; Noh, J.; Lee, I.; Kim, H. J.; Choi, S.; Seo, J.; Jeon, S.; Kim, T.-S.; Lee, J.-Y.; Choi, J. W. Wearable Textile Battery Rechargeable by Solar Energy. Nano Lett. 2013, 13, 5753-5761. 198. Yan, C.; Wang, X.; Cui, M.; Wang, J.; Kang, W.; Foo, C. Y.; Lee, P. S. Stretchable Silver-Zinc Batteries Based on Embedded Nanowire Elastic Conductors. Adv. Energy Mater. 2014, 4, DOI: 10.1002/aenm.201301396. 199. David, L.; Bhandavat, R.; Singh, G. MoS2/Graphene Composite Paper for Sodium-Ion Battery Electrodes. ACS Nano. 2014, 8, 1759-1770. 200. Nguyen, T. H.; Fraiwan, A.; Choi, S. Paper-based batteries: A review. Biosens. Bioelectron. 2014, 54, 640-649. 201. Lin, M.-C.; Gong, M.; Lu, B.; Wu, Y.; Wang, D.-Y.; Guan, M.; Angell, M.; Chen, C.; Yang, J.; Hwang, B.-J.; Dai, H. An ultrafast rechargeable aluminium-ion battery. Nature. 2015, 520, 324-328. 202. Chen, Z.; Hsu, P.-C.; Lopez, J.; Li, Y.; To, J. W. F.; Liu, N.; Wang, C.; Andrews, Sean C.; Liu, J.; Cui, Y.; Bao, Z. Fast and reversible thermoresponsive polymer switching materials for safer batteries. Nat. Energy. 2016, 1, 15009. 203. Wang, C.-Y.; Zhang, G.; Ge, S.; Xu, T.; Ji, Y.; Yang, X.-G.; Leng, Y. Lithium-ion battery structure that self-heats at low temperatures. Nature. 2016, 529, 515-518.


Page 42 of 46

Page 43 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

204. Oudenhoven, J. F. M.; Baggetto, L.; Notten, P. H. L. All-Solid-State Lithium-Ion Microbatteries: A Review of Various Three-Dimensional Concepts. Adv. Energy Mater. 2011, 1, 10-33. 205. Qiu, Y.; Li, G.; Hou, Y.; Pan, Z.; Li, H.; Li, W.; Liu, M.; Ye, F.; Yang, X.; Zhang, Y. Vertically Aligned Carbon Nanotubes on Carbon Nanofibers: A Hierarchical three-dimensional carbon nanostructure for high-energy flexible supercapacitors. Chem. Mater. 2015, 27, 11941200. 206. Wannapob, R.; Vagin, M. Y.; Jeerapan, I.; Mak, W. C. Pure Nanoscale Morphology Effect Enhancing the Energy Storage Characteristics of Processable Hierarchical Polypyrrole. Langmuir. 2015, 31, 11904-11913. 207. Wang, Q.; Yan, J.; Fan, Z. Carbon materials for high volumetric performance supercapacitors: design, progress, challenges and opportunities. Energy Environ. Sci. 2016, 9, 729-762. 208. Zheng, Y.; Yang, Y.; Chen, S.; Yuan, Q. Smart, stretchable and wearable supercapacitors: prospects and challenges. CrystEngComm. 2016. DOI: 10.1039/C5CE02510A. 209. Gong, S.; Zhao, Y.; Shi, Q.; Wang, Y.; Yap, L. W.; Cheng, W. Self-assembled Ultrathin Gold Nanowires as Highly Transparent, Conductive and Stretchable Supercapacitor. Electroanalysis. 2016, DOI: 10.1002/elan.201600081. 210. Lamberti, A.; Clerici, F.; Fontana, M.; Scaltrito, L. A Highly stretchable supercapacitor using laser-induced graphene electrodes onto elastomeric substrate. Adv. Energy Mater. 2016, DOI: 10.1002/aenm.201600050. 211. Yu, J.; Lu, W.; Pei, S.; Gong, K.; Wang, L.; Meng, L.; Huang, Y.; Smith, J. P.; Booksh, K. S.; Li, Q.; Byun, J.-H.; Oh, Y.; Yan, Y.; Chou, T.-W. Omnidirectionally Stretchable HighPerformance Supercapacitor Based on Isotropic Buckled Carbon Nanotube Films. ACS Nano. 2016, DOI: 10.1021/acsnano.6b00752. 212. Wen, Z.; Wang, X.; Mao, S.; Bo, Z.; Kim, H.; Cui, S.; Lu, G.; Feng, X.; Chen, J. Crumpled Nitrogen-Doped Graphene Nanosheets with Ultrahigh Pore Volume for HighPerformance Supercapacitor. Adv. Mater. 2012, 24, 5610-5616. 213. Wang, H.; Xu, Z.; Li, Z.; Cui, K.; Ding, J.; Kohandehghan, A.; Tan, X.; Zahiri, B.; Olsen, B. C.; Holt, C. M. B.; Mitlin, D. Hybrid Device Employing Three-Dimensional Arrays of MnO in Carbon Nanosheets Bridges Battery–Supercapacitor Divide. Nano Lett. 2014, 14, 1987-1994. 214. Kong, L.; Zhang, C.; Wang, J.; Qiao, W.; Ling, L.; Long, D. Free-Standing TNb2O5/Graphene Composite Papers with Ultrahigh Gravimetric/Volumetric Capacitance for LiIon Intercalation Pseudocapacitor. ACS Nano. 2015, 9, 11200-11208. 215. Li, Q.; Lu, X.-F.; Xu, H.; Tong, Y.-X.; Li, G.-R. Carbon/MnO2 Double-Walled Nanotube Arrays with Fast Ion and Electron Transmission for High-Performance Supercapacitors. ACS Appl. Mater. Interfaces. 2014, 6, 2726-2733. 43 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

216. Hyder, M. N.; Lee, S. W.; Cebeci, F. Ç.; Schmidt, D. J.; Shao-Horn, Y.; Hammond, P. T. Layer-by-Layer Assembled Polyaniline Nanofiber/Multiwall Carbon Nanotube Thin Film Electrodes for High-Power and High-Energy Storage Applications. ACS Nano. 2011, 5, 85528561. 217. Wang, Q.; Yan, J.; Fan, Z. Nitrogen-doped sandwich-like porous carbon nanosheets for high volumetric performance supercapacitors. Electrochim. Acta. 2014, 146, 548-555. 218. Guo, D.-C.; Mi, J.; Hao, G.-P.; Dong, W.; Xiong, G.; Li, W.-C.; Lu, A.-H. Ionic liquid C16mimBF4 assisted synthesis of poly(benzoxazine-co-resol)-based hierarchically porous carbons with superior performance in supercapacitors. Energy Environ. Sci. 2013, 6, 652-659. 219. Tang, H.; Wang, J.; Yin, H.; Zhao, H.; Wang, D.; Tang, Z. Growth of Polypyrrole Ultrathin Films on MoS2 Monolayers as high-performance supercapacitor electrodes. Adv. Mater. 2015, 27, 1117-1123. 220. Becker, C.; Amkreutz, D.; Sontheimer, T.; Preidel, V.; Lockau, D.; Haschke, J.; Jogschies, L.; Klimm, C.; Merkel, J. J.; Plocica, P.; Steffens, S.; Rech, B. Polycrystalline silicon thin-film solar cells: Status and perspectives. Sol. Energy Mater. Sol. Cells. 2013, 119, 112-123. 221. Wang, W.; Winkler, M. T.; Gunawan, O.; Gokmen, T.; Todorov, T. K.; Zhu, Y.; Mitzi, D. B. Device Characteristics of CZTSSe Thin-Film Solar Cells with 12.6% Efficiency. Adv. Energy Mater. 2014, 4. DOI: 10.1002/aenm.201301465. 222. Savin, H.; Repo, P.; von Gastrow, G.; Ortega, P.; Calle, E.; Garín, M.; Alcubilla, R. Black silicon solar cells with interdigitated back-contacts achieve 22.1% efficiency. Nat. Nanotechnol. 2015, 10, 624-628. 223. Nie, W.; Tsai, H.; Asadpour, R.; Blancon, J.-C.; Neukirch, A. J.; Gupta, G.; Crochet, J. J.; Chhowalla, M.; Tretiak, S.; Alam, M. A.; Wang, H.-L.; Mohite, A. D. High-efficiency solutionprocessed perovskite solar cells with millimeter-scale grains. Science. 2015, 347, 522-525. 224. Green, M. A.; Emery, K.; Hishikawa, Y.; Warta, W.; Dunlop, E. D. Solar cell efficiency tables (Version 45). Progress in Photovoltaics: Research and Applications. 2015, 23, 1-9. 225. Park, N.-G. Perovskite solar cells: an emerging photovoltaic technology. Mater. Today. 2015, 18, 65-72. 226. Song, M.; You, D. S.; Lim, K.; Park, S.; Jung, S.; Kim, C. S.; Kim, D.-H.; Kim, D.-G.; Kim, J.-K.; Park, J.; Kang, Y.-C.; Heo, J.; Jin, S.-H.; Park, J. H.; Kang, J.-W. Highly efficient and bendable organic solar cells with solution-processed silver nanowire electrodes. Adv. Funct. Mater. 2013, 23, 4177-4184. 227. Zhang, N.; Chen, J.; Huang, Y.; Guo, W.; Yang, J.; Du, J.; Fan, X.; Tao, C. A Wearable All-solid photovoltaic textile. Adv. Mater. 2016, 28, 263-269. 228. Bandodkar, A. J.; Wang, J. Wearable Biofuel Cells: A Review. Electroanalysis. 2016, DOI: 10.1002/elan.201600019. 44 ACS Paragon Plus Environment

Page 44 of 46

Page 45 of 46

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sensors

229. Katz, E. In Implantable biofuel cells operating in vivo: Providing sustainable power for bioelectronic devices: From biofuel cells to cyborgs, Advances in Sensors and Interfaces (IWASI), 2015 6th IEEE International Workshop on, 18-19 June 2015; pp 2-13. 230. Liu, D.; Shaojun, D. The Self-Powered Biosensors Based on Biofuel Cells. In Electrochemical Biosensors, Pan Stanford: 2015; pp 371-387. 231. Meredith, M. T.; Minteer, S. D. Biofuel Cells: Enhanced Enzymatic Bioelectrocatalysis. Annual Review of Analytical Chemistry. 2012, 5, 157-179. 232. Ogawa, Y.; Takai, Y.; Kato, Y.; Kai, H.; Miyake, T.; Nishizawa, M. Stretchable biofuel cell with enzyme-modified conductive textiles. Biosens. Bioelectron. 2015, 74, 947-952. 233. Stidham, S. E.; Chin, S. L.; Dane, E. L.; Grinstaff, M. W. Carboxylated Glucuronic Polyamido-saccharides as Protein Stabilizing Agents. J. Am. Chem. Soc. 2014, 136, 9544-9547. 234. Paz-Alfaro, K. J.; Ruiz-Granados, Y. G.; Uribe-Carvajal, S.; Sampedro, J. G. Trehalosemediated thermal stabilization of glucose oxidase from Aspergillus niger. J. Biotechnol. 2009, 141, 130-136. 235. Hwang, E. T.; Gu, M. B. Enzyme stabilization by nano/microsized hybrid materials. Engineering in Life Sciences. 2013, 13, 49-61. 236. Nguyen, K. V.; Giroud, F.; Minteer, S. D. Improved Bioelectrocatalytic Oxidation of Sucrose in a Biofuel Cell with an Enzyme Cascade Assembled on a DNA Scaffold. J. Electrochem. Soc. 2014, 161, H930-H933. 237. Arechederra, M. N.; Addo, P. K.; Minteer, S. D. Poly(neutral red) as a NAD+ reduction catalyst and a NADH oxidation catalyst: Towards the development of a rechargeable biobattery. Electrochim. Acta. 2011, 56, 1585-1590. 238. Campbell, A. S.; Jeong, Y. J.; Geier, S. M.; Koepsel, R. R.; Russell, A. J.; Islam, M. F. Membrane/Mediator-Free Rechargeable Enzymatic Biofuel Cell Utilizing Graphene/Single-Wall Carbon Nanotube Cogel Electrodes. ACS Appl. Mater. Interfaces. 2015, 7, 4056-4065. 239. Murata, K.; Kajiya, K.; Nakamura, N.; Ohno, H. Direct electrochemistry of bilirubin oxidase on three-dimensional gold nanoparticle electrodes and its application in a biofuel cell. Energy Environ. Sci. 2009, 2, 1280-1285. 240. Trifonov, A.; Herkendell, K.; Tel-Vered, R.; Yehezkeli, O.; Woerner, M.; Willner, I. Enzyme-Capped Relay-Functionalized Mesoporous Carbon Nanoparticles: Effective Bioelectrocatalytic Matrices for Sensing and Biofuel Cell Applications. ACS Nano. 2013, 7, 11358-11368. 241.

Senior, M. Novartis signs up for Google smart lens. Nat. Biotechnol. 2014, 32, 856-856.

242. Chen, F.; Deng, P.; Wan, J.; Zhang, D.; Vasilakos, A. V.; Rong, X. Data mining for the internet of things: literature review and challenges. Int. J. Distrib. Sen. Netw. 2015, 2015, 12-12. 45 ACS Paragon Plus Environment

ACS Sensors

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

243. Chen, M.; Leung, V. C. M.; Mao, S. Directional Controlled Fusion in Wireless Sensor Networks. Mobile Networks and Applications. 2009, 14, 220-229. 244. Wu, X.; Zhu, X.; Wu, G. Q.; Ding, W. Data mining with big data. IEEE Transactions on Knowledge and Data Engineering. 2014, 26, 97-107. 245. Doukas, C.; Maglogiannis, I. In Managing Wearable Sensor Data through Cloud Computing, Cloud Computing Technology and Science (CloudCom), 2011 IEEE Third International Conference on, Nov. 29 2011-Dec. 1 2011; pp 440-445. 246. Liu, C.; Yang, C.; Zhang, X.; Chen, J. External integrity verification for outsourced big data in cloud and IoT: A big picture. Future Generation Computer Systems. 2015, 49, 58-67. 247. Lin, C.; Wang, P.; Song, H.; Zhou, Y.; Liu, Q.; Wu, G. A differential privacy protection scheme for sensitive big data in body sensor networks. Annals of Telecommunications. 2016, 111. 248. Guan, Z.; Yang, T.; Du, X. Achieving secure and efficient data access control for cloudintegrated body sensor networks. Int. J. Distrib. Sen. Netw. 2015, 2015, 142-142. 249. Zhang, C.; Li, C.; Zhang, J. A Secure privacy-preserving data aggregation model in wearable wireless sensor networks. Journal of Electrical and Computer Engineering. 2015, 2015, 9.


Page 46 of 46

Wearable Chemical Sensors: Present ... - American Chemical Society

Recommend Documents