Subscriber access provided by The Libraries of the | University of North Dakota
Article
Patterned Photonic Nitrocellulose for Pseudo-Paper Microfluidics Bingbing Gao, Hong Liu, and Zhongze Gu Anal. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.analchem.6b00802 • Publication Date (Web): 18 Apr 2016 Downloaded from http://pubs.acs.org on April 20, 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.
Analytical Chemistry 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 32
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
Analytical Chemistry
[Prepared for publication as an Article in Analytical Chemistry]
Ms. ID:
Patterned Photonic Nitrocellulose for Pseudo-Paper Microfluidics
Bingbing Gao, Hong Liu,* and Zhongze Gu*
State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
*To whom correspondence should be addressed. Email:
[email protected],
[email protected] Submitted: March 1, 2016
1 ACS Paragon Plus Environment
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
Abstract We report a pseudo-paper microfluidic chip based on patterned photonic nitrocellulose. The photonic nitrocellulose is fabricated using self-assembled monodisperse SiO2 nanoparticles as template. The SiO2 nanoparticles form a photonic crystal having close-packed hexagonal structure in the microchannels, so the resulted nitrocellulose has complementary inverse-opal structure. After lamination, a hollow channel is obtained which is partially filled with the photonic nitrocellulose. Owing to the highly-ordered photonic structure of the pseudo-paper chip, the flow profile of aqueous solution wicking through the channel is more uniform than conventional paper microfluidic chip. It is also found that the wicking rate of aqueous solution can be easily manipulated by changing the diameter of the self-assembled monodisperse SiO2 nanoparticles which determines the pore size of the photonic nitrocellulose. The fluorescent enhancement property of the photonic nitrocellulose is used to increase the fluorescent intensity for multiplex detection of two cancer biomarkers. Label-free detection of human immunoglobin G based on the structure color of the photonic nitrocellulose is also demonstrated.
2 ACS Paragon Plus Environment
Page 2 of 32
Page 3 of 32
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
Analytical Chemistry
Introduction Recently, paper-based microfluidics has emerged as a promising solution to the need for chemical analysis under resource-limited conditions.
1-4
As a simple, rapid and inexpensive platform, paper-
based analytical device has contributed to a number of interesting applications in diagnostics, environmental monitoring, and food safety.
5-7
So far, almost all of the methods developed
for fabricating paper-based microfluidic device are top-down methods, which are usually carried out by selectively delivering energy, chemicals, or both onto a sheet of paper to divide it into hydrophilic channels and hydrophobic barriers.8-16 Aqueous solutions are then driven along the hydrophilic channels by capillary action. In despite of the advantages of these top-down fabrication methods such as being simple, fast and low cost, several critical problems arise. First, the surface roughness of the cellulose paper limits the lateral resolution for fabricating microfluidic channel. Even using photolithography, the smallest width of the channel that can be fabricated is about 200 µm, which is much larger than that of traditional plastic or glass microfluidic channels.17-21 Second, the random distribution of cellulose microfibers leads to a non-uniform flow profile which affects the reproducibility of redissolution and mixing of preloaded chemical reagents, and therefore decreases the analytical reproducibility.22 Finally, the presence of cellulose microfibers in the channel decreases the flow rate which increases the assay time.23,24 3 ACS Paragon Plus Environment
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
To partially solve these problems, we have previously reported a template-based bottom-up method for high-resolution fabrication of paper-based microfluidic chip with both channel width and height down to 10 µm.
25
We first printed wax on a
hydrophilic substrate to form the channel template. Then cellulose suspension was filled into the channel by blade-coating it on the substrate. After drying, the capillary channel fabricated using this method was partially filled with cellulose microfibers. The channel is similar to hollow channel previously reported by Crooks and co-workers.
24,26
The flow rate of aqueous
sample in the channel was also highly increased. However, the reproducibility of the analytical device was still affected by the randomly-distributed cellulose microfibers in the channel. Here, we introduced self-assembled technique to fabricate highly-ordered photonic nitrocellulose (NC) in the channel template to solve this problem. Instead of filling the wax channel template with random cellulose microfibers, we filled it with monodispersed SiO2 nanoparticles.27,28 After the self-assembly process, the nanoparticles form a hexagonal close-packed photonic nanostructure.29-32 We then filled the channel with NC solution. After solvent evaporation, the SiO2 in the channel was etched with HF leaving the photonic NC with complementary inverse-opal structure in the channel.33 The microfluidic chip fabricated using this method is named pseudo-paper microfluidic chip by us to distinguish with conventional microfluidic chips having randomlydistributed cellulose microfibers. Using the photonic pseudopaper microfluidic devices, human immunoglobulin G (IgG), 4 ACS Paragon Plus Environment
Page 4 of 32
Page 5 of 32
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
Analytical Chemistry
carcino-embryonic antigen （CEA) and alpha-fetoprotein (AFP） was quantitatively analyzed. The photonic pseudo-paper microfluidic chip is important for the following reasons. First, the highly-ordered nanostructure reduces the surface roughness of the fabricated microfluidic channel down to nanometer to submicrometer scale. The flow profile in the pseudo-paper microfluidic channel with highlyordered nanostructure is more uniform than that in conventional paper microfluidic channel so that the reproducibility of reagent redissolution and mixing can be improved. Secondly, the wicking rate of aqueous sample in the channel can be manipulated by simply changing the diameter of the self-assembled monodisperse SiO2 nanoparticles which determines the pore size of the photonic NC channel. Third, the photonic paper has unique optical properties which are useful for chemical analysis. For example, based on the structural color of the photonic NC, label-free detection can be carried out for simple and inexpensive assays.34,35 The fluorescence enhancement property of the photonic material can also be utilized to amplify the fluorescent signal for developing highly-sensitive analytical methods.36,37 Finally, the fabrication of the pseudo-paper microfluidic device is fast and inexpensive. In the lab, an individual can produce ∼120 devices per hour at a cost of
