Vertical Gold Nanowires Stretchable Electrochemical Electrodes

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Vertical Gold Nanowires Stretchable Electrochemical Electrodes Qingfeng Zhai, Yan Wang, Shu Gong, Yunzhi Ling, Lim Wei Yap, Yiyi Liu, Joseph Wang, George P. Simon, and Wenlong Cheng Anal. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.analchem.8b03423 • Publication Date (Web): 11 Oct 2018 Downloaded from http://pubs.acs.org on October 16, 2018

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Analytical Chemistry

Vertical Gold Nanowires Stretchable Electrochemical Electrodes Qingfeng Zhai1,2, Yan Wang1,2, Shu Gong1,2, Yunzhi Ling1,2, Lim Wei Yap1,2, Yiyi Liu1,2, Joseph Wang3,

George. P. Simon2,4, Wenlong Cheng1,2,5* 1

Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia;

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New Horizon Research Centre, Monash University, Clayton, Victoria 3800, Australia;

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Department of Nanoengineering, University of California, San Diego, La Jolla, CA, USA;

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Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia;

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The Melbourne Centre for Nanofabrication, Clayton, Victoria 3800, Australia;

*Correspondence author. Email: W. L. Cheng ([email protected])

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Analytical Chemistry 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

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ABSTRACT Conventional electrodes produced from gold or glassy carbon are outstanding electrochemical platforms for biosensing applications due to their chemical inertness and wide electrochemical window, but are intrinsically rigid and planar in nature. Hence, it is challenging to seamlessly integrate them with soft and curvilinear biological tissues for real-time wearable or implantable electronics. In this work, we demonstrate that vertically gold nanowires (v-AuNWs) possess an enokitake-like structure, with the nanoparticle head on one side and nanowires tail on the opposite side of the structure, and can serve as intrinsically-stretchable, electrochemical electrodes due to the stronger nanowire-elastomer bonding forces preventing from interfacial delamination under strains. The exposed head side of the electrode comprising v-AuNWs can achieve a detection limit for H2O2 of 80 µM, with a linear range of 0.2 mM—10.4 mM at 20% strain with a reasonably high sensitivity using chronoamperometry. This excellent electrochemical performance in the elongated state, in conjunction with low-cost wet-chemistry fabrication, demonstrates that v-AuNWs electrodes may become a next-generation sensing platform for conformally-integrated, in-vivo biodiagnostics.

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INTRODUCTION In-vivo sensors which can be worn on or implanted within the body for continuous monitoring of vital health signs without affecting normal human activities, have attracted considerable attention in recent years13

. The wearable sensor with the capability of being able to non-invasively and continuously collect biometric

information such as blood pressure4-5, heart rate6-7, body motion8 and sweat chemicals9 including ions, pH, glucose, lactate, can potentially lead to a paradigm shift from current hospital-centered diagnostics to diagnostics, which can be measured anytime and anywhere in a way that is not only comfortable but largely forgotten by the user10. Such sensors would significantly improve the quality of life, particularly for elderly people or patients11-12. One of key design parameters for such application is to achieve highly stretchable sensors which have similar moduli to that of biological tissues to allow conformal contact13. Despite encouraging progress made to date in detecting physical signals, such as wrist pulses and body motions, the success in also detecting biochemical signals remains much more limited14-15.

The conventional electroanalytical detections of biochemical species are based on gold disks, platinum rods and glassy carbon because of their chemical inertness and wide electrochemical windows. However, such rigid and planar electrodes incompatible with soft and curvilinear biological tissues. This poses challenges for integrating traditional electrochemical electrodes with intrinsically stretchable biological systems. To achieve stretchable sensors, extrinsic16 and intrinsic materials design17-18 represent two viable strategies. For example, pre-strain and designed serpentine patterning have been demonstrated to be successful techniques for generating stretchable electroanalytical systems for glucose, lactate and ion detections19-21.

Nanomaterials have been used in the development of stretchable, sensing electrodes. One dimensional (1D) nanomaterials have been demonstrated to be superior candidates for wearable electronics by constructing percolation networks on the surface or inside elastomeric substrates22. In particular, metal nanowires such as

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ultrathin gold nanowires4, 23-25, copper nanowires26-30 silver nanowires10, and carbon nanotubes31-32 have led to a series of wearable sensors for detecting wrist pulses and body motions for example. However, there have been few reports to date in the literature relating to 1D nanomaterials-based, stretchable electrochemical biosensors until recently. Gold has been the primary choice as the electrochemical electrode due to attributes including high chemical inertness, great biocompatibility, wide electrochemical window, high electrical conductivity, and facile surface modification based on thiol-Au chemistry. It has been reported, for example, that it is possible to achieve real-time monitoring of chemicals released from living cells using gold nanotubes under stretched states33-35. The conductivity of 1D percolation network is usually related to the inherent conductivity of the 1D nanomaterials, surface capping ligands, the synthesis methods and the concentration of 1D nanomaterial for percolation. Such kind of percolation nanowire networks usually either suffer from low conductivity or limited surface area, preventing them from being used as electrochemical electrodes.

In addition to percolation configuration, 1D nanowires or nanotubes can also be grown in a vertically aligned fashion, normal to supporting substrates and achieved by chemical vapor deposition

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, templated

electrodeposition37 and solution-based seed-guided crystallographic growth38. However, all of these fabrication methods are based on rigid substrates. It is non-trivial to extend them to soft elastomeric substrates for constructing stretchable electrodes.

Here, we demonstrate that elastomer-bonded vertically gold nanowires (v-AuNWs) can serve as intrinsically stretchable electrochemical electrodes. In separate studies, we described their capabilities of detecting physical parameters including pressure and strains38,39-41. We have also demonstrated that v-AuNWs have enokitake-like configuration with nanoparticles (head) on one side and nanowires (tail) on the other. By direct growth on EcoFlex substrate, we can have tail-bonded v-AuNWs electrodes with head side exposed (Type I, Scheme 1A); by using PMMA as a sacrificial layer, head-bonded v-AuNWs electrodes can be

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produced with the tail side exposed (Type II, Scheme 1B). Interestingly, in stretching tests, the two types of electrodes exhibit quite different electrochemical properties in H2SO4 and Fe(CN)63-/4- electrolytes. By systematically comparing the key parameters such as electrochemically-active surface area (EASA), peak current retention, peak to peak separation, it was found that the type I electrodes are more tolerant to stretching, with a lesser change in the above parameters during extension. Using H2O2 as the model system, which is a key product of numerous (oxidase-based) enzymatic reactions, it was further demonstrated that the Type I head exposed v-AuNWs electrodes exhibit excellent H2O2-sensing performance under stretched states, with a detection limit of 80 µM, a sensitivity of 67.47 µA·mM-1·cm-2 and a linear range of 0.2 mM—11.6 mM. This performance is comparable to that for conventional rigid gold electrodes.

EXPERIMENTAL SECTION Chemicals and Reagents. (3-Aminopropyl)triethoxysilane (APTES), HAuCl4, NaBH4, sodium citrate, L-ascorbic acid (L-AA), 4-Mercaptobenzoic acid (MBA), K3Fe(CN)6, K4Fe(CN)6, KCl, H2O2, NaH2PO4, Na2HPO4 were purchased from Sigma-Aldrich. Poly(methyl methacrylate) (PMMA) was purchased from MicroChem Corp. (Westborough, USA). Eco-flex (00-30) was purchased from Smooth-On, Inc. All of the chemicals were of at least analytical grade and the water used throughout all experiments was purified by a Milli-Q system (resistivity > 18 MΩ·cm-1). The Fabrication of Head Side Exposed Type I Stretchable Electrode. Type I v-AuNWs electrodes were obtained through direct growth on Eco-flex substrate using the modified seed-guided method. Briefly, Part A and Part B of EcoFlex 00-30 were completely mixed, at a weight ratio of 1:1, and then cast on to silicon wafer (D=15 cm) through spin-coating (400 rpm/min, 30 s). After being completely cured in the oven (60℃), EcoFlex was transferred in Harrick plasma cleaner to be pretreated with O2 plasma for 12 min, and then immersed in APTES solution (0.3 mL APTES/100 mL ethanol) for 2 h to functionalize with amino moieties.

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After washing with ethanol and water to remove the excess of APTES, EcoFlex was immersed in citratestabilized Au seeds solution with a nanoparticle size of ~10 nm, as confirmed by TEM in Figure S242 for 2 h to ensure all Au seeds were adsorbed completely on the surface of EcoFlex through the electrostatic interaction, and then washed with water to remove the excess of Au seeds. Finally, the head side exposed type I electrode was obtained by immersing Au seeds adsorbed EcoFlex in ethanol solution containing HAuCl4 (12 mM), MBA (980 µM) and L-AA (29 mM) for 3 min. After rinsing with ethanol and dried using N2, the v-AuNWs based type I obtained electrodes were used for characterization and electrochemical properties test. The Fabrication of Tail Side exposed Type II Stretchable Electrodes. Tail side exposed v-AuNWbased Type II electrodes were fabricated on PMMA with the same method mentioned above, and then peeled off using polydimethylsiloxane (PDMS). PMMA was used as the sacrificial layer and spin-coated on the to the surface of silicon wafer (3000 rpm/min, 60 s), and transferred onto a hot-plate to heat for 2 min at 180℃. After cooling down to room temperature, the PMMA/silicon wafer was treated by O2 plasma cleaner for 5 min, and then successively immersed in APTES solution, Au seed solution, and growth solution. After being rinsed with ethanol and dried by N2, PMMA/silicon wafer with v-AuNWs was then had a layer of PDMS (400 rpm/min, 30 s) applied by further spin coating. The tail side of the exposed Type II stretchable electrode was then obtained through peeling off the Au film from PMMA/silicon wafer, after curing overnight in an oven (60℃). Electrochemical Properties Characterization. The v-AuNWs ensembles described above and based on two types of stretchable electrodes were cut to the same size and used as the working electrode. Ag/AgCl and platinum wire was used as the reference electrode and counter electrode, respectively. Cyclic voltammetry (CV) was used to record the performance of two types of stretchable electrodes in 1 M H2SO4 and 5 mM Fe(CN)63-/4- at different strains from 0% to 50%. H2O2 detection. The electrode that used for H2O2 detection was fabricated with the designed pattern, v-

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AuNWs based Type I electrode were both acted as working electrode and counter electrode, and the Ag/AgCl paste that coated on the surface of v-AuNWs acted as the reference electrode (Figure S1). CV and chronoamperometry were used for H2O2 detection at 0% and 20% strain.

RESULTS AND DISCUSSION Fabrication and Characterization of v-AuNWs Based Two Types of Stretchable Electrodes. Head side exposed Type I electrode were obtained by growing v-AuNWs directly on the surface of EcoFlex with the modified seed-guided crystallographic growth method38 (Scheme 1A). Firstly, the surface hydrophilicity of EcoFlex was improved through O2 plasma treatment, and then functionalized with APTES to produce an amino-based, positively charged surface. Citrate-stabilized Au nanoparticles were then adsorbed on to the surface of EcoFlex by electrostatic interaction, and they acted as the seeds for v-AuNWs growth. After growth in a reaction solution containing ligand (MBA), reducing agent (L-AA) and Au source (HAuCl4) for 3 min, the EcoFlex was completely covered by v-AuNWs, and the color changed to golden yellow (insert Figure 1A). Scanning electron microscopy (SEM) characterization (Figure 1A) revealed that the head side exposed v-AuNWs based Type I stretchable electrode consisted of closely-packed gold nanoparticles with a diameter of some 10 nm. Tail side exposed Type II stretchable electrodes were fabricated through peeling off AuNWs by PDMS that were grown on PMMA/silicon wafer based on the same method for Type I electrode (Scheme 1B). After peeling, it can be clearly seen that the color of tail side exposed type II electrode was completely dark (insert Figure 1B), and SEM characterization in Figure 1B revealed that Type II stretchable electrode were composed of dense, standing nanowires. In addition, SEM of the cross-sectional characterization in Figure 1C further shows that the resultant two types of stretchable electrodes were composed of dense enokitake-like v-AuNWs. The head side exposed Type I electrode was a pyknotic film formed by closely-packed gold nanoparticles, while the tail side exposed Type II electrode was composed of dense AuNWs. Furthermore, the diameter and

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the length of v-AuNWs were about 9.2 nm and 5 µm, respectively. Most importantly, the dense arrangement of v-AuNWs on stretchable substrates demonstrated the high conductivity necessary for electrodes with good performance. In the previous studies39-41, we have demonstrated that the length of the nanowires could be adjusted from 1.5 µm to 14 µm, while the diameter is insensitive to the change of experimental conditions. Stretching Test in H2SO4. Before use for detection, the Au electrodes are usually activated and pretreated in H2SO4 solution to clean the surface43. In this work, the electrochemical properties of obtained two types of v-AuNWs based stretchable electrodes were characterized in 1 M H2SO4 electrolyte, and the parameters about the Au electrode can also be determined, such as the EASA, peak current, peak potentials, roughness factor (RF). In order to eliminate the interference, before electrochemical properties characterization, each type of stretchable electrode was firstly scanned in 1 M H2SO4 electrolyte with the scan rate of 0.1 V/s for at least 20 cycles until stable CV curves were obtained, and a series of CV curves recorded for different stretched states (Figure 2 A and B). The voltammogram for each type of electrode shows the typical features for a gold electrode, with gold oxidation starting at about 1.3 V, and the resultant gold oxide then being electrochemically reduced in the negative potentials sweep at the potential about 0.9 V. With increasing strain, it can be clearly seen that the reduction current of both types of electrode decreased, but the current of Type II electrode decreased to a much greater degree than the type I electrode. The potentials of Type I stretchable electrodes involving the reduction of the formed Au oxide showed almost no change, while Type II electrodes did shift slightly with the strain. By integrating the charge required for reducing the gold oxide formed in the positive sweep, the EASA of the obtained two types of electrodes can be determined according to the following equations44-45. 𝐸𝐴𝑆𝐴 = 𝑄/𝑐

(1)

𝑄 = 𝐴/𝑣

(2)

where Q is the charge required for the reduction of the Au oxide formed in the positive scan; c is the required

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charge for reduction of a monolayer of Au oxide (386 µC/cm2); A is the reduction current peak area and v is the scan rate. A comparison of the results for the two types of electrodes in EASA that along with the strains have shown in Figure 2C. It can be seen that both were decreased due to the resistance of electrodes increase. They have almost the same EASA at the strain range from 0%—20%, but the tail side exposed Type II electrode decreased more remarkably than head side exposed Type I electrode from strains 20% to 50%. In addition, the change of current density (reduction peak current/EASA) in Figure 2D showed that the tail side exposed Type II electrode decreased from about 346.34 µA/cm2 to 159.59 µA/cm2 when the strain was varied from 0% to 50%; while head side exposed Type I electrode was almost able to maintain 258.23±8.92 µA/cm2 for varying strain. In order to more clearly and visually observe the difference in the electrochemical properties of the two types of v-AuNWs based stretchable electrodes under the stretched state, comparison of the results of the peak current, current retention, the peak potential, the quantity of the electric charge (Q) and RF were measured and the results presented in Table 1. Apart from the EASA and current density that have been discussed above, the current retention and Q retention of head side exposed Type I electrode both been reduced to 0.63 of the initial state (0% strain), while the two values of tail side exposed Type II electrode decreased to 0.13 and 0.33, respectively. Another key parameter, RF, which plays an important role in overall performance, was also decreased with increasing strain. Both demonstrated almost the same RF value under 20% strain, but the head side exposed Type I electrode was much greater than the tail side exposed Type II electrode, in the strain range from 20% to 50%. Stretching Test in Fe(CN)63-/4-. Fe(CN)63- and Fe(CN)64- represents a commonly-used redox couple to evaluate the performance of the electrode. In this work, the CV curves of two types of v-AuNWs based stretchable electrodes were recorded using different stretched states in 5 mM Fe(CN)63-/4-, as shown in Figure

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3A and B. Both CV scans showed a couple of typical redox peaks, and the peak current (oxidation peak and reduction peak) both decreased with increasing strain. The current retention of the tail side exposed Type II electrode is nearly the same as the head side exposed Type I electrode in the strain range 0%—20%, decreasing more significantly than the Type I electrode from strains 20% to 50% (Figure 3C). In addition, from the comparison of the results in Table 2, it can be seen that the current retention of head side exposed Type I electrode still can maintain more than 0.92 of the initial state, even at 50% strain, but Type II electrode has decreased to 0.64. Conversely, the peak-to-peak separations of both increased with increasing strain, although the increased peak separation of type II electrode was much greater than for the Type I electrode. From the comparison results in Figure 3D and Table 2, it can be clearly seen that from 0% strain to 50% strain, peak separation of type II electrode has increased from 0.19 V to 1.03 V, while type I electrode only increased 0.3 V (from 0.38 V to 0.68 V). From the above results comparing the electrochemical properties of the two types of v-AuNWs based stretchable electrodes in H2SO4 and Fe(CN)63-/4- electrolytes, it can be clearly seen that the electrochemical properties of head side exposed Type I electrode are much better than those of the tail side exposed Type II electrode in stretched state. The Type I electrode exhibited less significant changes in key parameters including EASA, peak current retention, peak to peak separation, than those for the Type II electrode. This is due to the fact that the conductivity of the head side exposed Type I electrode was relatively less sensitive to applied strains (Figure S3). For the strain range of 0% - 20%, the resistance changes for both types weren’t significant; while from 20% to 100% strain, the resistance of tail side exposed Type II electrode increased much more significantly than the head side exposed Type I electrode. This is due to the stronger bonding interaction between head side exposed Type I electrode and elastomeric substrate than that for tail exposed Type II electrode. The APTES serve as bifunctional linker with amine moieties bonded gold nanowires and the other end chemically bonded to elastomeric substrate. Such an adhesion mechanism does not exist for the tail side

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exposed Type II electrode. The consistent results along with the proposed stretching mechanism supported by detailed morphological studies reported in our recently publications40,41. Sensing Application. Based on the excellent tensile properties of the head side exposed Type I electrode, and in order to investigate its potential application in fabricating electrochemical sensor, H2O2 was chosen as the model target for analysis in view of its common use for amperometric biosensing involving many biological enzyme-induced reaction46-47, such as glucose oxidase for glucose oxidation and lactate oxidase for lactate oxidation. To perform the electrochemical study for H2O2 reduction, v-AuNWs based head side exposed type I stretchable three electrode systems were fabricated with the assistance of a specially-designed mask (Figure S1). Figure 4A shows the corresponding CV curves in phosphate buffer solution (pH=7.4) before and after addition of 2 mM H2O2. The head side exposed Type I electrode exhibits a high reduction peak current towards H2O2, due to the excellent catalytic ability of gold48. Chronoamperometry was used to evaluate the sensitivity of Type I electrode for H2O2 detection, and the current response at different applied potentials upon the successive addition of H2O2 in Figure S4 show the response at -0.4 V is higher than other applied potentials (-0.3V, 0.3 V and 0.4). This was chosen as the optimal potential for H2O2 detection and the corresponding current response at 0% and 20% strain upon successive addition of H2O2, as shown in Figure 4 B and C, respectively. For the v-AuNWs based Type I electrode at 0% and 20% strain, a subsequent addition of H2O2 to the stirring phosphate buffer led to a remarkable increase in the reduction current, demonstrating the good catalytic properties of v-AuNWs. Both of them can reach the 95% steady state response within 5 s. The calibration curve of increased current (∆I) versus the concentration of H2O2 is shown in Figure 4D. The curves exhibited good linear relationships over the ranges 0.2 mM—10.4 mM (R2=0.9950) for 0% strain and 0.2 mM—11.6 mM (R2=0.9959) for 20% strain with the sensitivity of about 243.43 µA·mM-1·cm-2 and 67.47 µA·mM-1·cm-2, respectively, which is comparable with the reported literatures49-50. In addition, based on a signal-to-noise factor of 3 (S/N=3), the detection limit at 0% and 20% strain can be calculated to be 50 µM

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and 80 µM, respectively.

CONCLUSIONS A new intrinsically-stretchable, electrochemical-sensing platform using enokitake-like standing gold nanowires has been developed. By evaluating the changes of key electrochemical parameters, it was found that nanoparticle-exposed electrodes can tolerate more during mechanical stretching test due to strong nanowire-elastomer bonding interactions. Using H2O2 as the model system, it was demonstrated that there was excellent electrochemical sensing performance in the stretched state using nanowire-bonded electrodes, which may be able to be extended to a myriad of other biological analytes such as glucose and lactate. Considering the versatility of potentially growing v-AuNWs electrodes on other elastomeric surfaces, these materials and methodology represents an advance to conformally integrating electrochemical sensors with soft biological systems. ASSOCIATED CONTENT

Additional information about the fabrication of head side exposed electrochemical sensor device for H2O2 detection with the assistance of special designed mask, TEM of the citrate-stabilized Au nanoparticles, resistance change of the two types of electrode under different stretching magnitudes, and the current response upon the successive addition of H2O2 at different applied potential. This material is available free of charge via the Internet at http://pubs.acs.org. AUTHOR INFORMATION

Notes The authors declare no competing financial interest. ACKNOWLEDGMENTS

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This work is financially supported by ARC Discovery projects DP170102208 and DP180101715. This work was performed in part at the Melbourne Centre for Nanofabrication (MCN) in the Victorian Node of the Australian National Fabrication Facility (ANFF).

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REFERENCES (1)

Gong, S.; Cheng, W. L. Adv. Energy Mater. 2017, 7, 1700648.

(2)

Jason, N. N.; Ho, M. D.; Cheng, W. L. J. Mater. Chem. C 2017, 5, 5845.

(3)

Bandodkar, A. J.; Wang, J. Trends Biotechnol. 2014, 32, 363.

(4) Gong, S.; Schwalb, W.; Wang, Y.; Chen, Y.; Tang, Y.; Si, J.; Shirinzadeh, B.; Cheng, W. Nat. Commun. 2014, 5, 3132. (5)

Pan, L. J.; Chortos, A.; Yu, G. H.; Wang, Y. Q.; Isaacson, S.; Allen, R.; Shi, Y.; Dauskardt, R.; Bao, Z. N. Nat. Commun. 2014, 5, 3002.

(6) Shin, K. Y.; Lee, J. S.; Jang, J. Nano Energy 2016, 22, 95. (7) Shao, Q.; Niu, Z. Q.; Hirtz, M.; Jiang, L.; Liu, Y. J.; Wang, Z. H.; Chen, X. D. Small 2014, 10, 1466. (8) Wang, Y.; Gong, S.; Wang, S. J.; Simon, G. P.; Cheng, W. L. Mater. Horiz. 2016, 3, 208. (9) Gao, W.; Emaminejad, S.; Nyein, H. Y. Y.; Challa, S.; Chen, K. V.; Peck, A.; Fahad, H. M.; Ota, H.; Shiraki, H.; Kiriya, D.; Lien, D. H.; Brooks, G. A.; Davis, R. W.; Javey, A. Nature 2016, 529, 509. (10) Ho, M. D.; Ling, Y.; Yap, L. W.; Wang, Y.; Dong, D.; Zhao, Y.; Cheng, W. Adv. Funct. Mater. 2017, 27, 1700845. (11) Lee, H.; Choi, T. K.; Lee, Y. B.; Cho, H. R.; Ghaffari, R.; Wang, L.; Choi, H. J.; Chung, T. D.; Lu, N. S.; Hyeon, T.; Choi, S. H.; Kim, D. H. Nat. Nanotechnol. 2016, 11, 566. (12) Imani, S.; Bandodkar, A. J.; Mohan, A. M. V.; Kumar, R.; Yu, S. F.; Wang, J.; Mercier, P. P. Nat. Commun. 2016, 7, 11650. (13) Zhao, S.; Li, J.; Cao, D.; Zhang, G.; Li, J.; Li, K.; Yang, Y.; Wang, W.; Jin, Y.; Sun, R. ACS Appl. Mater. Inter. 2017, 9 (14), 12147. (14) Bandodkar, A. J.; Jeerapan, I.; Wang, J. ACS Sensors 2016, 1, 464. (15) Bao, Z. N.; Chen, X. D. Adv. Mater. 2016, 28, 4177. (16) Niu, Z. Q.; Dong, H. B.; Zhu, B. W.; Li, J. Z.; Hng, H. H.; Zhou, W. Y.; Chen, X. D.; Xie, S. S. Adv. Mater. 2013, 25, 1058 (17) Lipomi, D. J.; Lee, J. A.; Vosgueritchian, M.; Tee, B. C. K.; Bolander, J. A.; Bao, Z. N. Chem. Mater. 2012, 24, 373. (18) Liu, Z. Y.; Qi, D. P.; Guo, P. Z.; Liu, Y.; Zhu, B. W.; Yang, H.; Liu, Y. Q.; Li, B.; Zhang, C. G.; Yu, J. C.; Liedberg, B.; Chen, X. D. Adv. Mater. 2015, 27, 6230. (19) Bandodkar, A. J.; Jeerapan, I.; You, J. M.; Nunez-Flores, R.; Wang, J. Nano Lett. 2016, 16, 721. (20) Jeerapan, I.; Sempionatto, J. R.; Pavinatto, A.; You, J. M.; Wang, J. J. Mater. Chem. A 2016, 4, 18342. (21) Bandodkar, A. J.; Nunez-Flores, R.; Jia, W. Z.; Wang, J. Adv. Mater. 2015, 27, 3060. (22) Gong, S.; Cheng, W. L. Adv. Electron. Mater. 2017, 3, 1600314. (23) Gong, S.; Lai, D. T.; Su, B.; Si, K. J.; Ma, Z.; Yap, L. W.; Guo, P.; Cheng, W. Adv. Electron. Mater. 2015, 1, 1400063. (24) Gong, S.; Lai, D. T. H.; Wang, Y.; Yap, L. W.; Si, K. J.; Shi, Q. Q.; Jason, N. N.; Sridhar, T.; Uddin, H.; Cheng, W. L. ACS Appl. Mater. Inter. 2015, 7, 19700. (25) Gong, S.; Zhao, Y. M.; Yap, L. W.; Shi, Q. Q.; Wang, Y.; Bay, J.; Lai, D. T. H.; Uddin, H.; Cheng, W. L. Adv. Electron. Mater. 2016, 2, 1600121. (26) Yap, L.; Gong, S.; Tang, Y.; Zhu, Y. G.; Cheng, W. L. Sci. Bull. 2016, 61, 1624. (27) Jason, N. N.; Wang, S. J.; Bhanushali, S.; Cheng, W. L. Nanoscale 2016, 8, 16596. (28) Bhanushali, S.; Ghosh, P. C.; Simon, G. P.; Cheng, W. L. Adv. Mater. Inter. 2017, 4, 1700387. (29) Jason, N. N.; Shen, W.; Cheng, W. L. ACS Appl. Mater. Inter. 2015, 7, 16760. (30) Zhao, S.; Han, F.; Li, J.; Meng, X.; Huang, W.; Cao, D.; Zhang, G.; Sun, R.; Wong, C. P. Small 2018, 1800047. (31) Lipomi, D. J.; Vosgueritchian, M.; Tee, B. C.; Hellstrom, S. L.; Lee, J. A.; Fox, C. H.; Bao, Z., Nat. Nanotechnol. 2011, 6 (12), 788. (32) Park, S.; Vosguerichian, M.; Bao, Z., Nanoscale 2013, 5 (5), 1727. (33) Liu, Y. L.; Jin, Z. H.; Liu, Y. H.; Hu, X. B.; Qin, Y.; Xu, J. Q.; Fan, C. F.; Huang, W. H. Angew. Chem. Int. Ed. 2016, 55, 4537. (34) Liu, Y. L.; Qin, Y.; Jin, Z. H.; Hu, X. B.; Chen, M. M.; Liu, R.; Amatore, C.; Huang, W. H. Angew. Chem. Int. Ed. 2017, 56, 9454. (35) Wang, Y. W.; Liu, Y. L.; Xu, J. Q.; Qin, Y.; Huang, W. H. Anal. Chem. 2018, 90, 5977.

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(36) Gonzalez Arellano, D. L.; Burnett, E. K.; Demirci Uzun, S.; Zakashansky, J. A.; Champagne, V. K., 3rd; George, M.; Mannsfeld, S. C. B.; Briseno, A. L., J. Am. Chem. Soc. 2018, 140 (26), 8185. (37) Sander, M. S.; Prieto, A. L.; Gronsky, R.; Sands, T.; Stacy, A. M., Adv. Mater. 2002, 14 (9), 665. (38) He, J. T.; Wang, Y. W.; Feng, Y. H.; Qi, X. Y.; Zeng, Z.; Liu, Q.; Teo, W. S.; Gan, C. L.; Zhang, H.; Chen, H. Y. ACS Nano 2013, 7, 2733. (39) Wang, Y.; Gong, S.; Gómez, D.; Ling, Y.; Yap, L. W.; Simon, G. P.; Cheng, W. ACS Nano 2018, 12, 8717. (40) Gong, S.; Wang, Y.; Yap, L. W.; Ling, Y.; Zhao, Y.; Dong, D.; Shi, Q.; Liu, Y.; Uddin, H.; Cheng, W. Nanoscale Horiz., 2018, DOI: 10.1039/c8nh00125a. (41) Wang, Y.; Gong, S.; Wang, S.; Yang, X.; Ling, Y., Yap, L. W.; Dong, D.; Simon, G. P.; Cheng, W. ACS Nano 2018, DOI: 10.1021/acsnano.8b0501910. (42) Gole, A.; Murphy, C. J. Chem. Mater. 2004, 16, 3633. (43) Hoogvliet, J.; Dijksma, M.; Kamp, B.; Van Bennekom, W., Anal. Chem. 2000, 72 (9), 2016. (44) Trasatti, S.; Petrii, O. A., Pure Appl. Chem. 1991, 63, 711. (45) Wang, C. H.; Yang, C.; Song, Y. Y.; Gao, W.; Xia, X. H. Adv. Funct. Mater. 2005, 15, 1267. (46) Bandodkar, A. J.; Jia, W. Z.; Yardimci, C.; Wang, X.; Ramirez, J.; Wang, J. Anal. Chem. 2015, 87, 394. (47) Jia, W. Z.; Bandodkar, A. J.; Valdes-Ramirez, G.; Windmiller, J. R.; Yang, Z. J.; Ramirez, J.; Chan, G.; Wang, J. Anal. Chem. 2013, 85, 6553. (48) Guo, S. J.; Wen, D.; Dong, S. J.; Wang, E. K. Talanta 2009, 77, 1510. (49) Ju, J.; Chen, W. Anal. Chem. 2015, 87, 1903. (50) Wang, N.; Han, Y.; Xu, Y.; Gao, C. Z.; Cao, X. Anal. Chem. 2015, 87, 457.

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Page 16 of 23

FIGURE CAPTIONS

Scheme 1. The fabrication process two types of stretchable electrodes. (A) tail-bonded v-AuNWs electrodes with head side exposed (Type I) and (B) head-bonded v-AuNWs electrodes with tail side exposed (Type II).

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Figure 1. SEM characterization of v-AuNWs based two types of stretchable electrodes. (A) Head side exposed Type I electrode; (B) Tail side exposed Type II electrode and (C) the cross sectional view. (Insert in A and B were the photograph of two types of stretchable electrodes, respectively.)

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Page 18 of 23

Figure 2. Electrochemical properties study of v-AuNWs based two types of stretchable electrodes in 1 M H2SO4 at different stretched states. (A) Head side exposed Type I electrode; (B) Tail side exposed Type II electrode; (C) The EASA that obtained through the integration of reduction peak area; (D) Current density obtained from the reduction peak current/EASA.

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Figure 3. Electrochemical properties study of v-AuNWs based two types of stretchable electrodes in 5 mM Fe(CN)63-/4- at different stretched states. (A) Head side exposed type I electrode; (B) Tail side exposed type II electrode; (C) The redox peak current retention; (D) peak-to-peak separation.

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Page 20 of 23

Figure 4. The detection performance of head side exposed type I electrode towards H2O2 in phosphate buffer solution (pH=7.4). (A) CV curves before and after addition of 2 mM H2O2; (B) and (C), chronoamperometric response of head side electrode upon the successive addition of H2O2 at −0.4 V at 0% strain and 20% strain, respectively. (D) The linear calibration curves of head side exposed Type I electrode between the increased current (∆I) and the concentration of H2O2 at 0% strain and 20% strain.

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Tables Table 1. The comparison results between head side exposed Type I electrode and tail side exposed Type II electrode scanned in 1 M H2SO4.

Head exposed (Type I)

Tail exposed (Type II)

Strain

Peak Current (µA)

Current Retention

Peak Potential (V)

Q (µC)

0% 10% 20% 30% 40% 50%

1078.87 1014.34 850.86 795.23 737.94 677.70

1.00 0.94 0.79 0.74 0.68 0.63

0.85 0.86 0.86 0.86 0.86 0.86

3352.13 2953.11 2739.86 2599.76 2463.21 2378.99

1.00 0.87 0.76 0.70 0.68 0.63

0% 10% 20% 30% 40% 50%

1427.29 1103.10 873.19 582.86 453.13 181.14

1.00 0.77 0.61 0.41 0.32 0.13

0.92 0.89 0.88 0.85 0.84 0.82

2066.89 1797.16 1587.02 1279.39 1154.34 687.56

1.00 0.87 0.77 0.62 0.56 0.33

Note: Q: the quantity of electric charge RF: roughness factor (EASA/GA)

EASA (cm2)

Current/EASA (µA/cm2)

GA (cm2)

RF

4.29 3.73 3.25 3.02 2.95 2.70

251.44 272.23 261.68 263.11 250.32 250.61

0.50 0.55 0.60 0.65 0.70 0.75

8.58 6.78 5.42 4.65 4.21 3.60

4.12 3.66 3.27 2.61 2.26 1.14

346.34 301.39 267.43 223.15 200.44 159.59

0.50 0.55 0.60 0.65 0.70 0.75

8.24 6.65 5.45 4.02 3.23 1.52

Q Retention

GA: geometric area

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Page 22 of 23

Table 2. The comparison results between head side exposed Type I electrode and tail side exposed Type II electrode scanned in 5 mM Fe(CN)63-/4-. Oxidation Peak Current (µA)

Oxidation Peak Potential (V)

Reduction Peak Current (µA)

Reduction Peak Potential (V)

0%

710.45

0.40

-680.89

10%

770.75

0.39

20%

745.23

0.44

30%

726.83

40%

683.22

50% 0% 10% 20% 30% 40% 50%

Strain

Head exposed (Type I)

Tail exposed (Type II)

Oxidation

Reduction

Peak Separation (V)

0.02

1.00

1.00

0.38

-732.72

0.03

1.08

1.07

0.36

-718.37

-0.01

1.05

1.05

0.45

0.46

-708.80

-0.04

1.02

1.04

0.50

0.51

-676.65

-0.08

0.96

0.99

0.59

651.07

0.56

-648.56

-0.12

0.92

0.95

0.68

771.80 772.78 746.52 666.96 591.14 497.60

0.37 0.39 0.43 0.50 0.61 0.79

-708.37 -725.73 -718.31 -656.60 -589.12 -495.64

0.18 0.15 0.12 0.04 -0.07 -0.24

1 1.00 0.97 0.86 0.77 0.64

1 1.02 1.01 0.93 0.83 0.70

0.19 0.24 0.31 0.46 0.68 1.03

Current Retention

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For TOC only

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Vertical Gold Nanowires Stretchable Electrochemical Electrodes

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