Name: fabrication of polydimethylsiloxane (pdms)-based flexible surface-enhanced raman scattering (sers) substrate for ultrasensitive detection
Uploaded: 2023-11-17T14:00:00.000+00:00
Duration: 3 min 33 s
Description: Watch this Scientific Journal Video about Development and Application of SERS Flexible Substrates Using Synthesized AgNPs at JoVE.com

该研究得到了国家自然科学基金（批准号61974004和61931018）以及国家重点研发计划（批准号:2021YFB3200100）的支持。该研究感谢北京大学电子显微镜实验室提供电子显微镜。此外，这项研究还感谢崔莹和北京大学地球与空间科学学院在拉曼测量方面的帮助。

1. 纳米粒子的合成
<ol><li>硝酸银溶液的制备<ol><li>使用精密称量天平，测量 0.0017 g AR 级硝酸银（AgNO3，参见 材料表），并将其加入 10 mL 去离子 （DI） 水中。搅拌混合物以产生 10-3 mol/L AgNO3 溶液。</li>
	</ol></li>
	<li>银-氨络合物的制备<ol><li>取 1 mL AR 级氨水 （NH3.H2O，见 材料表）使用注射器，并在搅拌的同时逐滴加入硝酸银溶液中。当溶液变得透明时，停止逐滴添加。</li>
	</ol></li>
	<li>葡萄糖溶液的制备<ol><li>使用精密称量天平，测量 0.36 g AR 级葡萄糖粉（参见 材料表），并将其加入 10 mL 去离子水中。彻底搅拌混合物以产生 0.2 M 葡萄糖溶液。</li>
	</ol></li>
	<li>银纳米粒子（AgNPs）的合成<ol><li>使用移液枪以30分钟的间隔将30μL银氨复合物（在步骤1.2中制备）加入葡萄糖溶液（在步骤1.3中制备）。重复此过程 4-6 次，同时搅拌直到溶液变黄。</li>
	</ol></li>
</ol>2. 柔性基板的制备
<ol><li>PDMS衬底的制备<ol><li>为了合成PDMS底物，取约5g PDMS A溶液，并以1:10的比例加入B溶液（来自市售试剂盒，参见 材料表）。</li>
		<li>搅拌并充分混合 PDMS A 和 B 溶液。</li>
		<li>将混合的PDMS转移到方形培养皿中，然后在80°C烤箱中烘烤2小时。</li>
		<li>通过上述过程固化后，使用手术刀沿着培养皿的深色网格切割PDMS，形成尺寸约为1 cm x 1 cm的小PDMS立方体。</li>
	</ol></li>
	<li>表面改性<ol><li>对上述小PDMS片段进行等离子体处理。使用手持式等离子处理器（参见 材料表）并将其在PDMS表面上方约5-10厘米处来回移动，以进行表面等离子体处理。</li>
		<li>利用等离子体处理器对表面进行修饰，诱导在PDMS表面上形成羟基，使其亲水27。</li>
	</ol></li>
	<li>使用 APTES 进行修改<ol><li>制备10%APTES溶液（参见 材料表）。</li>
		<li>将步骤2.2中获得的表面改性PDMS浸入APTES溶液中，并静置10小时。这使得APTES能够与PDMS表面上的羟基结合。</li>
	</ol></li>
	<li>AgNP的自组装<ol><li>将步骤2.3中获得的PDMS底物浸入步骤1.4中合成的AgNPs溶液中10小时。这将AgNP自组装到PDMS衬底上，从而形成最终的柔性SERS检测衬底。</li>
	</ol></li>
</ol>

用于 R6G 和 Thiram 的 SERS 检测的柔性衬底的制备

<ol>
	<li>Zheng, F., Ke, W., Shi, L., Liu, H., Zhao, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasmonic+Au-Ag+janus+nanoparticle+engineered+ratiometric+surface-enhanced+Raman+scattering+aptasensor+for+ochratoxin+A+detection.">Plasmonic Au-Ag janus nanoparticle engineered ratiometric surface-enhanced Raman scattering aptasensor for ochratoxin A detection.</a> Analytical Chemistry. 91 (18), 11812-11820 (2019).</li><li>Zhou, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size-tunable+gold+aerogels:+a+durable+and+misfocus-tolerant+3D+substrate+for+multiplex+SERS+detection.">Size-tunable gold aerogels: a durable and misfocus-tolerant 3D substrate for multiplex SERS detection.</a> Advanced Optical Materials. 9 (17), 2100352 (2021).</li><li>Fan, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Graphene+oxide+and+shape-controlled+silver+nanoparticle+hybrids+for+ultrasensitive+single-particle+surface-enhanced+Raman+scattering+(SERS)+sensing.">Graphene oxide and shape-controlled silver nanoparticle hybrids for ultrasensitive single-particle surface-enhanced Raman scattering (SERS) sensing.</a> Nanoscale. 6 (9), 4843-4851 (2014).</li><li>Xu, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Graphene-veiled+gold+substrate+for+surface-enhanced+Raman+spectroscopy.">Graphene-veiled gold substrate for surface-enhanced Raman spectroscopy.</a> Advanced Materials. 25 (6), 928-933 (2013).</li><li>Li, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Graphene-coated+Si+nanowires+as+substrates+for+surface-enhanced+Raman+scattering.">Graphene-coated Si nanowires as substrates for surface-enhanced Raman scattering.</a> Applied Surface Science. 541, 0169-4332 (2021).</li><li>Chin, C. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+sensitivity+enhancement+of+multi-shaped+silver-nanoparticle-decorated+hydrophilic+PVDF-based+SERS+substrates+using+solvating+pretreatment.">High sensitivity enhancement of multi-shaped silver-nanoparticle-decorated hydrophilic PVDF-based SERS substrates using solvating pretreatment.</a> Sensors and Actuators: B. Chemistry. 347, 130614 (2021).</li><li>Volpe, G., Noack, M., Acimovic, S. S., Reinhardt, C., Quidant, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Near-field+mapping+of+plasmonic+antennas+by+multiphoton+absorption+in+poly(methyl+methacrylate).">Near-field mapping of plasmonic antennas by multiphoton absorption in poly(methyl methacrylate).</a> Nano Letters. 12 (9), 4864-4868 (2012).</li><li>Novikov, S. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fractal+shaped+periodic+metal+nanostructures+atop+dielectric-metal+substrates+for+SERS+applications.">Fractal shaped periodic metal nanostructures atop dielectric-metal substrates for SERS applications.</a> ACS Photonics. 7 (7), 1708-1715 (2020).</li><li>Li, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=300+mm+wafer-level,+ultra-dense+arrays+of+Au-capped+nanopillars+with+sub-10+nm+gaps+as+reliable+SERS+substrates.">300 mm wafer-level, ultra-dense arrays of Au-capped nanopillars with sub-10 nm gaps as reliable SERS substrates.</a> Nanoscale. 6 (21), 12391-12396 (2014).</li><li>Mecker, L. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+melamine+detection+in+multiple+sample+matrices+with+a+portable+Raman+instrument+using+surface-enhanced+Raman+spectroscopy-active+gold+nanoparticles.">Selective melamine detection in multiple sample matrices with a portable Raman instrument using surface-enhanced Raman spectroscopy-active gold nanoparticles.</a> Analytica Chimica Acta. 733, 48-55 (2012).</li><li>Shao, J. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PLLA+nanofibrous+paper-based+plasmonic+substrate+with+tailored+hydrophilicity+for+focusing+SERS+detection.">PLLA nanofibrous paper-based plasmonic substrate with tailored hydrophilicity for focusing SERS detection.</a> ACS Applied Materials &amp; Interfaces. 7, 5391-5399 (2015).</li><li>Chen, Y. M., Ge, F. Y., Guang, S. Y., Cai, Z. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-cost+and+large-scale+flexible+SERS-cotton+fabric+as+a+wipe+substrate+for+surface+trace+analysis.">Low-cost and large-scale flexible SERS-cotton fabric as a wipe substrate for surface trace analysis.</a> Applied Surface Science. 436, 111-116 (2018).</li><li>Yang, L., Zhen, S. J., Li, Y. F., Huang, C. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silver+nanoparticles+deposited+on+graphene+oxide+for+ultrasensitive+surface-enhanced+Raman+scattering+immunoassay+of+cancer+biomarker.">Silver nanoparticles deposited on graphene oxide for ultrasensitive surface-enhanced Raman scattering immunoassay of cancer biomarker.</a> Nanoscale. 10, 11942-11947 (2018).</li><li>Creedon, N. C., Lovera, P., Furey, A., O'Riordan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transparent+polymer-based+SERS+substrates+templated+by+a+soda+can.">Transparent polymer-based SERS substrates templated by a soda can.</a> Sensors and Actuators, B. 259, 64-74 (2018).</li><li>Shiohara, A., Langer, J., Polavarapu, L., Marzan, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solution+processed+polydimethylsiloxane/gold+nanostar+flexible+substrates+for+plasmonic+sensing.">Solution processed polydimethylsiloxane/gold nanostar flexible substrates for plasmonic sensing.</a> Nanoscale. 6, 9817-9823 (2014).</li><li>Guo, H. Y., Jiang, D., Li, H. B., Xu, S. P., Xu, W. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+efficient+construction+of+silver+nanosphere+dimers+on+poly+(dimethylsiloxane)+sheets+for+surface-enhanced+Raman+scattering.">Highly efficient construction of silver nanosphere dimers on poly (dimethylsiloxane) sheets for surface-enhanced Raman scattering.</a> Journal of Physical Chemistry C. 117, 564-570 (2013).</li><li>Park, S., Lee, J., Ku, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transparent+and+flexible+surface-enhanced+Raman+scattering+(SERS)+sensors+based+on+gold+nanostar+arrays+embedded+in+silicon+rubber+film.">Transparent and flexible surface-enhanced Raman scattering (SERS) sensors based on gold nanostar arrays embedded in silicon rubber film.</a> ACS Applied Materials Interfaces. 9, 44088-44095 (2017).</li><li>Li, L. M., Chin, W. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+fabrication+of+a+flexible+and+transparent+Ag+nanocubes@+PDMS+film+as+a+SERS+substrate+with+high+performance.">Rapid fabrication of a flexible and transparent Ag nanocubes@ PDMS film as a SERS substrate with high performance.</a> ACS Applied Materials &amp; Interfaces. 12 (33), 37538-37548 (2020).</li><li>Yang, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+detection+using+two-dimensional+shell-isolated+nanoparticle+film.">Quantitative detection using two-dimensional shell-isolated nanoparticle film.</a> Journal of Raman Spectroscopy. 48, 919-924 (2017).</li><li>Fortuni, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+synthesis+of+Au-shelled+Ag+nanoparticles+on+PDMS+for+flexible,+long-life,+and+broad+spectrum-sensitive+SERS+substrates.">In situ synthesis of Au-shelled Ag nanoparticles on PDMS for flexible, long-life, and broad spectrum-sensitive SERS substrates.</a> Chemical Communications. 53 (82), 11298-11301 (2017).</li><li>Wu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Graphene+oxide+scroll+meshes+prepared+by+molecular+combing+for+transparent+and+flexible+electrodes.">Graphene oxide scroll meshes prepared by molecular combing for transparent and flexible electrodes.</a> Advanced Materials Technologies. 2 (2), 1600231 (2017).</li><li>Li, Z. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silver+nanowire-templated+molecular+nanopatterning+and+nanoparticle+assembly+for+surface-enhanced+Raman+scattering.">Silver nanowire-templated molecular nanopatterning and nanoparticle assembly for surface-enhanced Raman scattering.</a> Chemistry-A European Journal. 25 (45), 10561-10565 (2019).</li><li>Zhan, H. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfer+printing+for+preparing+nanostructured+PDMS+film+as+flexible+SERS+active+substrate.">Transfer printing for preparing nanostructured PDMS film as flexible SERS active substrate.</a> Composites Part B: Engineering. 84, 222-227 (2016).</li><li>West, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Searching+for+better+plasmonic+materials.">Searching for better plasmonic materials.</a> Laser &amp; Photonics Reviews. 4, 795-808 (2010).</li><li>Anastassiades, M., Lehotay, S. J., &#352;tajnbaher, d., Schenck, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+and+easy+multiresidue+method+employing+acetonitrile+extraction/partitioning+and+&amp;#34;dispersive+solid-phase+extraction&amp;#34;+for+the+determination+of+pesticide+residues+in+produce.">Fast and easy multiresidue method employing acetonitrile extraction/partitioning and &amp;#34;dispersive solid-phase extraction&amp;#34; for the determination of pesticide residues in produce.</a> Journal of AOAC International. 86 (2), 412-431 (2003).</li><li>Zhu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+green+chemistry+synthesis+of+Ag+nanoparticles+and+their+concentrated+distribution+on+PDMS+elastomer+film+for+more+sensitive+SERS+detection.">A green chemistry synthesis of Ag nanoparticles and their concentrated distribution on PDMS elastomer film for more sensitive SERS detection.</a> , (2017).</li><li>Damalas, C. A., Eleftherohorinos, I. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pesticide+exposure,+safety+issues,+and+risk+assessment+indicators.">Pesticide exposure, safety issues, and risk assessment indicators.</a> International Journal of Environmental Research and Public Health. 8 (5), 1402-1419 (2011).</li><li>Zannotti, M., Rossi, A., Giovannetti, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SERS+activity+of+silver+nanosphere,+triangular+nanoplates,+hexagonal+nanoplates+and+quasi-spherical+nanoparticles:+effect+of+shape+and+morphology.">SERS activity of silver nanosphere, triangular nanoplates, hexagonal nanoplates and quasi-spherical nanoparticles: effect of shape and morphology.</a> Coatings. 10, 288 (2020).</li><li>Zhu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Large-scale+fabrication+of+ultrasensitive+and+uniform+surface-enhanced+Raman+scattering+substrates+for+the+trace+detection+of+pesticides.">Large-scale fabrication of ultrasensitive and uniform surface-enhanced Raman scattering substrates for the trace detection of pesticides.</a> Nanomaterials. 8 (7), 520 (2018).</li><li>Lu, H., Zhu, L., Zhang, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mixing+assisted+&amp;#34;hot+spots&amp;#34;+occupying+SERS+strategy+for+highly+sensitive+in+situ+study.">Mixing assisted &amp;#34;hot spots&amp;#34; occupying SERS strategy for highly sensitive in situ study.</a> Analytical Chemistry. 90 (7), 4535-4543 (2018).</li><li>Mao, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+surface-enhanced+Raman+scattering+sensors+based+on+nanopillar+forests+realized+by+an+oxygen-plasma-stripping-of-photoresist+technique.">Microfluidic surface-enhanced Raman scattering sensors based on nanopillar forests realized by an oxygen-plasma-stripping-of-photoresist technique.</a> Small. 10 (1), 127-134 (2014).</li><li>Zhang, C. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small+and+sharp+triangular+silver+nanoplates+synthesized+utilizing+tiny+triangular+nuclei+and+their+excellent+SERS+activity+for+selective+detection+of+Thiram+residue+in+soil.">Small and sharp triangular silver nanoplates synthesized utilizing tiny triangular nuclei and their excellent SERS activity for selective detection of Thiram residue in soil.</a> ACS Applied Materials and Interfaces. 9, 17387-17398 (2017).</li><li>Zhu, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+dithiocarbamate+pesticides+with+a+spongelike+surface-enhanced+raman+scattering+substrate+made+of+reduced+graphene+oxide-wrapped+silver+nanocubes.">Detection of dithiocarbamate pesticides with a spongelike surface-enhanced raman scattering substrate made of reduced graphene oxide-wrapped silver nanocubes.</a> ACS Applied Materials and Interfaces. 9, 39618-39625 (2017).</li><li>Zhu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+sensitive+and+label-free+determination+of+thiram+residue+using+surface-enhanced+Raman+spectroscopy+(SERS)+coupled+with+paper-based+microfluidics.">Highly sensitive and label-free determination of thiram residue using surface-enhanced Raman spectroscopy (SERS) coupled with paper-based microfluidics.</a> Analytical Methods. 9, 6186-6193 (2017).</li><li>Yu, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gold-nanorod-coated+capillaries+for+the+SERS-based+detection+of+Thiram.">Gold-nanorod-coated capillaries for the SERS-based detection of Thiram.</a> ACS Applied Nano Materials. 2 (1), 598-606 (2019).</li><li>Zhang, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+and+non-invasive+surface-enhanced+Raman+spectroscopy+(SERS)+detection+of+chlorpyrifos+in+fruits+using+disposable+paper-based+substrates+charged+with+gold+nanoparticle/halloysite+nanotube+composites.">Rapid and non-invasive surface-enhanced Raman spectroscopy (SERS) detection of chlorpyrifos in fruits using disposable paper-based substrates charged with gold nanoparticle/halloysite nanotube composites.</a> Mikrochim Acta. 189, 189-197 (2022).</li><li>Lee, C. H., Tian, L., Singamaneni, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Paper-based+SERS+swab+for+rapid+trace+detection+on+real-world+surfaces.">Paper-based SERS swab for rapid trace detection on real-world surfaces.</a> ACS Applied Materials and Interfaces. 2, 3429-3435 (2010).</li><li>Cheng, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drug+preconcentration+and+direct+quantification+in+biofluids+using+3D-printed+paper+cartridge.">Drug preconcentration and direct quantification in biofluids using 3D-printed paper cartridge.</a> Biosensors and Bioelectronics. 189, 113266-113277 (2021).</li></ol>

作者声明没有利益冲突。

本研究引入了一种柔性SERS底物，通过化学改性将AgNPs与PDMS键合，并取得了优异的性能。在颗粒合成过程中，特别是在银氨络合物合成（步骤1.2）中，溶液的颜色起着至关重要的作用。滴加过多的氨水会对AgNPs的合成质量产生不利影响，可能导致检测结果不成功。合成过程中应注意底物改性（步骤2.2）;否则，AgNP可能无法与PDMS正确结合，从而导致检测性能下降。
在实际制备中，SERS底物的检测性能可能表现出不稳定性22。这可以通过改变物质的溶剂来优化。例如，使用乙腈作为Thiram的溶剂比使用乙醇产生更好的结果。此外，Thiram 的质量会影响检测到的 SERS 信号，这强调了在检测过程中确保所用试剂在其有效期内的重要性。
与其他研究36,37,38相比，本研究提出的SERS柔性底物检测方法简单明了。AgNPs可以通过简单的方法轻松合成，避免了复杂的实验条件和环境以及复杂的制造过程。基材环保，不引入有害污染物。然而，需要注意的是，由于AgNPs周围的葡萄糖层，会削弱银颗粒的增强作用，这表明需要进一步提高SERS底物的增强因子（EF）。使用本研究方法制备的SERS柔性底物在生物分子检测方面也需要进一步探索。
本研究提出的柔性SERS底物在现实生活中具有适用性，丰富了农药残留检测方法，具有重要意义。此外，在未来的应用中，柔性SERS底物在生物医学应用方面具有巨大的潜力。

表面增强拉曼散射（SERS）作为拉曼散射的一种，具有灵敏度高、检测条件温和等优点，甚至可以实现单分子检测1,2,3,4。金属纳米结构，如金和银，通常用作SERS基板，以实现物质检测5,6。纳米结构表面的电磁耦合增强在SERS应用中起着重要作用。具有不同尺寸、形状、粒子间距离和成分的金属纳米结构可以聚集起来产生许多"热点"，由于局部表面等离子体共振而产生强烈的电磁场 7,8。许多研究已经开发了具有不同形态的金属纳米颗粒作为SERS底物，证明了它们在实现SERS增强方面的有效性9,10。
柔性SERS衬底具有广泛的应用，其纳米结构能够产生SERS效应沉积在柔性衬底上，便于在曲面上直接检测。柔性SERS底物用于检测和收集不规则、非平面或曲面上的分析物。常见的柔性SERS基材包括纤维、聚合物薄膜和氧化石墨烯薄膜11,12,13,14。其中，聚二甲基硅氧烷（PDMS）是应用最广泛的高分子材料之一，具有透明度高、拉伸强度高、化学稳定性高、无毒、附着力等优点15,16,17。PDMS具有较低的拉曼截面，因此其对拉曼信号的影响可以忽略不计18。由于PDMS预聚物是液态的，因此可以通过热或光固化，从而提供了高度的可控性和便利性。基于PDMS的SERS衬底是相对常见的柔性SERS衬底，在以前的研究中已被用于嵌入各种金属纳米颗粒，用于检测具有示范性性能的不同生化物质19,20。
在SERS衬底的制备中，纳米间隙结构的制备至关重要。物理沉积技术具有高扩展性、均匀性和可重复性等优点，但通常需要良好的真空条件和专用设备，限制了其实际应用21。此外，使用传统的沉积技术在几纳米尺度上制造纳米结构仍然具有挑战性22。因此，通过化学方法合成的纳米颗粒可以通过各种相互作用吸附到柔性透明薄膜上，从而促进金属结构在纳米尺度上的自组装。为了确保成功吸附，可以通过物理或化学修饰薄膜表面来改变其表面亲水性来调整相互作用23。与金纳米颗粒相比，银纳米颗粒表现出更好的SERS性能，但它们的不稳定性，特别是它们在空气中对氧化的敏感性，导致SERS增强因子（EF）迅速降低，影响底物性能24。因此，开发一种稳定的颗粒方法至关重要。
农药残留的存在引起了人们的极大关注，因此迫切需要能够快速检测和识别现场食品中各种危险化学品的可靠方法25,26。柔性SERS基材在实际应用中具有独特的优势，特别是在食品安全领域。本文介绍了一种通过将合成的葡萄糖包被银纳米颗粒（AgNPs）键合到PDMS底物上来制备柔性SERS底物的方法（图1）。葡萄糖的存在可以保护AgNPs，减轻空气中的银氧化。该底物表现出优异的检测性能，能够检测低至10-10 M的罗丹明6G（R6G）和低至 10-8 M的农药硫兰，具有良好的均匀性。此外，柔性基板可用于通过粘接和取样进行检测，具有众多潜在的应用场景。

<table><tbody><tr><td>Ammonia (NH&lt;sub&gt;3.&lt;/sub&gt;H&lt;sub&gt;2&lt;/sub&gt;O, 25%)</td><td>Beijing Chemical Works</td><td></td><td></td></tr><tr><td>APTES (98%)</td><td>Beyotime</td><td>ST1087</td><td></td></tr><tr><td>BD-20AC Laboratory Chrona Treater</td><td>Electro-Technic Products Inc.</td><td>12051A</td><td></td></tr><tr><td>D-glucose</td><td>Beijing Chemical Works</td><td></td><td></td></tr><tr><td>Environmental Scanning electron microscope (ESEM)</td><td>FEI</td><td>QUANTA 250</td><td></td></tr><tr><td>Raman microscope</td><td>Horiba JY</td><td>LabRAM HR Evolution</td><td></td></tr><tr><td>Rhodamine 6G</td><td>Beijing Chemical Works</td><td></td><td></td></tr><tr><td>Silicone Elastomer Base and Silicone Elastomer Curing Agent</td><td>Dow Corning Corporation</td><td>SYLGARD 184</td><td></td></tr><tr><td>Silver nitrate</td><td>Beijing Chemical Works</td><td></td><td></td></tr><tr><td>Thiram (C&lt;sub&gt;6&lt;/sub&gt;H&lt;sub&gt;12&lt;/sub&gt;N&lt;sub&gt;2&lt;/sub&gt;S&lt;sub&gt;2&lt;/sub&gt;, 99.9%)</td><td>Beijing Chemical Works</td><td></td><td></td></tr></tbody></table>

fabrication of polydimethylsiloxane (pdms)-based flexible surface-enhanced raman scattering (sers) substrate for ultrasensitive detection

本文介绍了一种用于表面增强拉曼散射（SERS）的柔性衬底的制备方法。通过硝酸银（AgNO3）和氨的络合反应合成了银纳米颗粒（AgNPs），然后使用葡萄糖还原。所得的AgNPs表现出均匀的尺寸分布，范围为20 nm至50 nm。随后，采用3-氨丙基三乙氧基硅烷（APTES）对已用氧等离子体表面处理的PDMS衬底进行改性。该过程有助于AgNPs在基板上的自组装。通过系统评估各种实验条件对衬底性能的影响，开发出具有优异性能和增强因子（EF）的SERS衬底。利用这种底物，R6G（罗丹明6G）的检测限为10-10 M，Thiram的检测限为10-8 M，令人印象深刻。该基质被成功用于检测苹果上的农药残留，结果非常令人满意。灵活的SERS基板在实际应用中显示出巨大的潜力，包括复杂场景中的检测。

本研究利用APTES开发了一种由葡萄糖包裹的合成AgNPs组成的柔性SERS底物，并利用APTES在PDMS上自组装，在实际农药检测应用中实现了优异的检测性能。R6G 和 Thiram 的检出限分别达到 10-10 M 和 10-8 M，增强因子 （EF） 为 1 x 10 5。此外，基材表现出均匀性。
使用改进的 Tollens 方法合成包裹在葡萄糖中的 AgNP28,29。这种AgNPs组装不仅产生了强烈的SERS信号，而且有效地屏蔽了AgNPs中的银免受氧化，从而保持了检测性能。从图2的环境扫描电子显微镜（ESEM）图像来看，合成的颗粒看起来相对均匀，大多数直径在40-50nm之间。AgNPs的外层被葡萄糖层包裹。这种结构为AgNPs的外层提供了介电层，并保护银颗粒在暴露于空气中时不被氧化，从而保持了SERS的性能。
很明显，AgNPs的间隙之间形成了强烈的增强电场，这是SERS信号的主要原因。因此，将AgNP密集固定在柔性基板上，以实现增强的性能（图3）。本研究开发的自组装SERS柔性基板简单、质量高、不含有毒有害物质，对环境友好。
本研究制备的SERS柔性衬底表现出优异的检测性能。要评估SERS底物，关键方面是其检测能力。在这里，定义了增强因子（EF）来评估基板的增强性能，并使用R6G（参见 材料表）来确定检测限。EF 由30 描述:
EF = （I SERS / IRAMAN） × （N拉曼 / NSERS）
R6G的峰位31 及其对应值如 表1所示。
在这项研究中，使用具有 10 倍和 50 倍物镜的 633 nm 激光获得拉曼光谱。测量过程中光谱采集的积分时间设置为10 s，入射激光功率为3.7 mW。通过在衬底上加入30 μL不同浓度的R6G溶液，并通过直接检测观察拉曼信号，图4表明该衬底表现出优异的检测能力，R6G的检测限达到10-10 M，表明检测性能强。随后，使用10-5 M R6G作为测试探针，计算出基板的增强因子（EF）为1 x 10 5（计算过程详见补充文件1），显示出显着的增强效果（图5）。
灵活的SERS基质能够检测农药。Thiram 是一种在水果和蔬菜种植中广泛使用的二硫代氨基甲酸酯 （DTC） 农药，旨在控制真菌病害并防止储存和运输过程中的变质32.然而，反复接触或摄入Thiram残留物可能会导致健康问题，如嗜睡、肌张力丧失和严重的胎儿畸形33,34。因此，在水果和蔬菜表面实现痕量硫胺检测至关重要。Thiram 的拉曼峰35 及其原因概述在表 2 中。
将不同浓度的Thiram应用于柔性底物，以评估其检测性能。 图6 显示，对于Thiram检测，其三个主要特征峰清晰，在10-8 M处达到检测限。
灵活的基板可实现实际检测。在日常生活中，农药残留有时会持续存在于水果表面。进食未经清洗的水果可能会对健康构成风险。在这项研究中，使用"粘贴和剥离"方法应用柔性SERS基质，将基质附着在苹果表面，然后将其取出进行检查。
图7说明，在这种方法下，实现了10-7 M Thiram的检测，具有相对清晰的谱线。因此，制备的柔性SERS基质可以促进"糊状剥离"检测方法，有效识别果实表面的农药残留，并提供有价值的实际应用。
本研究提出的柔性SERS衬底不仅表现出显著的检测性能，而且提供了实际应用场景。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/65595/65595fig01.jpg"> 图 1:PDMS 柔性 SERS 基板的示意图。 图示描绘了用于表面增强拉曼散射 （SERS） 实验的 PDMS（聚二甲基硅氧烷）柔性基板的设计。 <a href="https://www.jove.com/files/ftp_upload/65595/65595fig01large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/65595/65595fig02.jpg"> 图2:合成AgNP的ESEM图像。 环境扫描电子显微镜 （ESEM） 图像显示合成的 AgNPs（银纳米颗粒）。图像中的比例尺为 2 μm，AgNP 的直径范围约为 20 nm 至 50 nm。 <a href="https://www.jove.com/files/ftp_upload/65595/65595fig02large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/65595/65595fig03.jpg"> 图 3:AgNP 的仿真。 模拟显示AgNPs（银纳米颗粒），在颗粒之间的间隙中发生了显着的局部场增强。 <a href="https://www.jove.com/files/ftp_upload/65595/65595fig03large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/65595/65595fig04.jpg"> 图 4:不同 R6G 浓度的 SERS 信号。 针对不同浓度的R6G（罗丹明6G）获得的表面增强拉曼散射（SERS）信号。图中的峰位置与 表1中的峰位一致。 <a href="https://www.jove.com/files/ftp_upload/65595/65595fig04large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/65595/65595fig05.jpg"> 图 5:R6G 在柔性基板上的 SERS 信号。 从柔性基板上的10个随机点收集R6G（罗丹明6G）的表面增强拉曼散射（SERS）信号，以证明均匀性。 <a href="https://www.jove.com/files/ftp_upload/65595/65595fig05large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/65595/65595fig06.jpg"> 图 6:不同 Thiram 浓度的 SERS 信号。 针对不同浓度的Thiram获得的表面增强拉曼散射（SERS）信号。 <a href="https://www.jove.com/files/ftp_upload/65595/65595fig06large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/65595/65595fig07.jpg"> 图 7:Thiram 在果实表面的 SERS 信号。 使用"粘贴和剥离"方法从苹果表面获得的 Thiram 的表面增强拉曼散射 （SERS） 信号。检出限达到Thiram的10-7 M。 <a href="https://www.jove.com/files/ftp_upload/65595/65595fig07large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td>峰位 （cm-1）</td>
			<td>分配</td>
		</tr><tr><td>612</td>
			<td>C-C-C平面内弯曲振动</td>
		</tr><tr><td>774</td>
			<td>C-H拉伸</td>
		</tr><tr><td>1127</td>
			<td>C-H面内弯曲振动</td>
		</tr><tr><td>1180</td>
			<td>C-H 和 N-H 弯曲振动</td>
		</tr><tr><td>1310</td>
			<td>C=C拉伸</td>
		</tr><tr><td>1364</td>
			<td>C-C键的拉伸振动</td>
		</tr><tr><td>1509</td>
			<td>C-C键的拉伸振动</td>
		</tr><tr><td>1574</td>
			<td>C=O键的拉伸振动</td>
		</tr><tr><td>1647</td>
			<td>C-C键的拉伸振动</td>
		</tr></tbody></table>表1:R6G SERS频谱中的拉曼频移和频率模式分配。 表格列出了R6G（罗丹明6G）表面增强拉曼散射（SERS）光谱中的拉曼位移值及其相应的频率模式分配。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td>峰位 （cm-1）</td>
			<td>分配</td>
		</tr><tr><td>440</td>
			<td>CH3-N-C 变形 （δ （CH3-N-C））， C=S 拉伸 （υ（C=S））</td>
		</tr><tr><td>549</td>
			<td>S-S 对称拉伸 （υs （S-S））</td>
		</tr><tr><td>928</td>
			<td>C=S 拉伸 （υ （C=S））， C-N 拉伸 （υ （CH3-N））</td>
		</tr><tr><td>1136</td>
			<td>C-N拉伸（υ（C-N）），摇摆CH3模式（ρ（CH3））</td>
		</tr><tr><td>1388</td>
			<td>C-N拉伸（υ（C-N）），CH3对称变形（υ（C=S））</td>
		</tr></tbody></table>表2:Thiram SERS频谱中的拉曼频移和频率模式分配。 表格列出了Thiram表面增强拉曼散射（SERS）光谱中的拉曼位移值及其相应的频率模式分配。
补充文件1:增强系数（ER）的计算。<a href="https://www.jove.com/files/ftp_upload/65595/65595_Supplementary%20File%201.zip" target="_blank">请点击这里下载此文件。</a>

Watch this Scientific Journal Video about Development and Application of SERS Flexible Substrates Using Synthesized AgNPs at JoVE.com

作者聚焦:使用合成的 AgNP 开发与应用 SERS 柔性底物 

该协议描述了一种用于表面增强拉曼散射的柔性基板的制造方法。该方法已成功用于检测低浓度的R6G和Thiram。

基于聚二甲基硅氧烷（PDMS）的柔性表面增强拉曼散射（SERS）衬底的制备及其超灵敏检测

This article presents a fabrication method for a flexible substrate designed for Surface-Enhanced Raman Scattering (SERS). Silver nanoparticles (AgNPs) ...

该协议描述了制备SERS柔性底物，并将其应用于实际检测场景。该协议提供的SERS柔性基板是环保的，并具有良好的检测性能。银纳米粒子可以很容易地通过简单的容器合成，不需要复杂的实验条件和环境。在我们的实验室中，我们计划专注于研究通过本研究中使用的容器合成的银纳米颗粒。我们将探索增强其SERS检测能力的方法，并利用其独特的特性和特性来设计性能更好的SERS检测基板。

fabrication-polydimethylsiloxane-pdms-based-flexible-surface-enhanced

Nanyang Technological University

Research

JoVE Journal

Engineering

Fabrication of polydimethylsiloxane (PDMS)-Based Flexible Surface-Enhanced Raman Scattering (SERS) Substrate for Ultrasensitive Detection

2.1K 次观看.  Peking University. 该协议描述了制备SERS柔性底物，并将其应用于实际检测场景。该协议提供的SERS柔性基板是环保的，并具有良好的检测性能。银纳米粒子可以很容易地通过简单的容器合成，不需要复杂的实验条件和环境。在我们的实验室中，我们计划专注于研究通过本研究中使用的容器合成的银纳米颗粒。我们将探索增强其SERS检测能力的方法，并利用其独特的特性和特性来设计性能更?...

视频: 作者聚焦:使用合成的 AgNP 开发与应用 SERS 柔性底物 

Microfabricated Platforms for Mechanically Dynamic Cell Culture

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or fundamental cell biology studies is limited by current bioreactor technologies, which cannot simultaneously apply a variety of mechanical stimuli to cultured cells. In order to address this issue, we have developed a series of microfabricated platforms designed to screen for the effects of mechanical stimuli in a high-throughput format. In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and further demonstrate how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

微机械动态细胞培养平台

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or ...

科研

生物工程

The Visual Colorimetric Detection of Multi-nucleotide Polymorphisms on a Pneumatic Droplet Manipulation Platform

A simple and visual method to detect multi-nucleotide polymorphism (MNP) was performed on a pneumatic droplet manipulation platform on an open surface. This approach to colorimetric DNA detection was based on the hybridization-mediated growth of gold nanoparticle probes (AuNP probes). The growth size and configuration of the AuNP are dominated by the number of DNA samples hybridized with the probes. Based on the specific size- and shape-dependent optical properties of the nanoparticles, the number of mismatches in a sample DNA fragment to the probes is able to be discriminated. The tests were conducted via droplets containing reagents and DNA samples respectively, and were transported and mixed on the pneumatic platform with the controlled pneumatic suction of the flexible PDMS-based superhydrophobic membrane. Droplets can be delivered simultaneously and precisely on an open-surface on the proposed pneumatic platform that is highly biocompatible with no side effect of DNA samples inside the droplets. Combining the two proposed methods, the multi-nucleotide polymorphism can be detected at sight on the pneumatic droplet manipulation platform; no additional instrument is required. The procedure from installing the droplets on the platform to the final result takes less than 5 min, much less than with existing methods. Moreover, this combined MNP detection approach requires a sample volume of only 10 &#181;l in each operation, which is remarkably less than that of a macro system.

This work presents a simple and visual method to detect multi-nucleotide polymorphisms on a pneumatic droplet manipulation platform. With the proposed method, the entire experiment, including droplet manipulation and detection of multi-nucleotide polymorphisms, can be performed near 23 &#176;C without the aid of advanced instruments.

在气动操纵液滴平台多核苷酸多态性的视觉比色法检测

A simple and visual method to detect multi-nucleotide polymorphism (MNP) was performed on a pneumatic droplet manipulation platform on an open surface. ...

遗传学

Fabricating a UV-Vis and Raman Spectroscopy Immunoassay Platform

Immunoassays are used to detect proteins based on the presence of associated antibodies. Because of their extensive use in research and clinical settings, a large infrastructure of immunoassay instruments and materials can be found. For example, 96- and 384-well polystyrene plates are available commercially and have a standard design to accommodate ultraviolet-visible (UV-Vis) spectroscopy machines from various manufacturers. In addition, a wide variety of immunoglobulins, detection tags, and blocking agents for customized immunoassay designs such as enzyme-linked immunosorbent assays (ELISA) are available.
Despite the existing infrastructure, standard ELISA kits do not meet all research needs, requiring individualized immunoassay development, which can be expensive and time-consuming. For example, ELISA kits have low multiplexing (detection of more than one analyte at a time) capabilities as they usually depend on fluorescence or colorimetric methods for detection. Colorimetric and fluorescent-based analyses have limited multiplexing capabilities due to broad spectral peaks. In contrast, Raman spectroscopy-based methods have a much greater capability for multiplexing due to narrow emission peaks. Another advantage of Raman spectroscopy is that Raman reporters experience significantly less photobleaching than fluorescent tags1. Despite the advantages that Raman reporters have over fluorescent and colorimetric tags, protocols to fabricate Raman-based immunoassays are limited. The purpose of this paper is to provide a protocol to prepare functionalized probes to use in conjunction with polystyrene plates for direct detection of analytes by UV-Vis analysis and Raman spectroscopy. This protocol will allow researchers to take a do-it-yourself approach for future multi-analyte detection while capitalizing on pre-established infrastructure.

Nanoparticle-based optical probes have been designed as a vehicle for detecting antigens using Raman and UV-Vis spectroscopy. Here we describe a protocol for preparing such probes for a UV-Vis/Raman spectroscopy immunoassay in such a way to incorporate future multiplexing capabilities.

制造的UV-Vis和拉曼光谱免疫平台

Immunoassays are used to detect proteins based on the presence of associated antibodies. Because of their extensive use in research and clinical settings, ...

生物化学

Surface Enhanced Raman Spectroscopy Detection of Biomolecules Using EBL Fabricated Nanostructured Substrates

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules is reported. The entire sequence of relevant experimental steps is described, involving the fabrication of nanostructured substrates using electron beam lithography, immobilization of biomolecules on the substrates, and their characterization utilizing surface-enhanced Raman spectroscopy (SERS). Three different designs of nano-biological systems are employed, including protein A, glucose binding protein, and a dopamine binding DNA aptamer. In the latter two cases, the binding of respective ligands, D-glucose and dopamine, is also included. The three kinds of biomolecules are immobilized on nanostructured substrates by different methods, and the results of SERS imaging are reported. The capabilities of SERS to detect vibrational modes from surface-immobilized proteins, as well as to capture the protein-ligand and aptamer-ligand binding are demonstrated. The results also illustrate the influence of the surface nanostructure geometry, biomolecules immobilization strategy, Raman activity of the molecules and presence or absence of the ligand binding on the SERS spectra acquired.

We describe the fabrication and characterization of nano-biological systems interfacing nanostructured substrates with immobilized proteins and aptamers. The relevant experimental steps involving lithographic fabrication of nanostructured substrates, bio-functionalization, and surface-enhanced Raman spectroscopy (SERS) characterization, are reported. SERS detection of surface-immobilized proteins, and probing of protein-ligand and aptamer-ligand binding is demonstrated.

表面增强拉曼光谱检测生物分子利用EBL装配纳米衬底

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules ...

工程学

A Filter-based Surface Enhanced Raman Spectroscopic Assay for Rapid Detection of Chemical Contaminants

We demonstrate a method to fabricate highly sensitive surface-enhanced Raman spectroscopic (SERS) substrates using a filter syringe system that can be applied to the detection of various chemical contaminants. Silver nanoparticles (Ag NPs) are synthesized via reduction of silver nitrate by sodium citrate. Then the NPs are aggregated by sodium chloride to form nanoclusters that could be trapped in the pores of the filter membrane. A syringe is connected to the filter holder, with a filter membrane inside. By loading the nanoclusters into the syringe and passing through the membrane, the liquid goes through the membrane but not the nanoclusters, forming a SERS-active membrane. When testing the analyte, the liquid sample is loaded into the syringe and flowed through the Ag NPs coated membrane. The analyte binds and concentrates on the Ag NPs coated membrane. Then the membrane is detached from the filter holder, air dried and measured by a Raman instrument. Here we present the study of the volume effect of Ag NPs and sample on the detection sensitivity as well as the detection of 10 ppb ferbam and 1 ppm ampicillin using the developed assay.

A procedure for fabrication and performing the filter-based surface enhanced Raman spectroscopic (SERS) assay for the detection of chemical contaminants (i.e., pesticide ferbam and antibiotic ampicillin) is presented.

基于过滤器的表面增强拉曼光谱检测方法的化学污染物快速检测

We demonstrate a method to fabricate highly sensitive surface-enhanced Raman spectroscopic (SERS) substrates using a filter syringe system that can be ...

化学

Fabrication of Carbon Nanotube High-Frequency Nanoelectronic Biosensor for Sensing in High Ionic Strength Solutions

The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) 1-4 make them good candidates for high sensitivity biosensors. When a charged molecule binds to such a sensor surface, it alters the carrier density5 in the sensor, resulting in changes in its DC conductance. However, in an ionic solution a charged surface also attracts counter-ions from the solution, forming an electrical double layer (EDL). This EDL effectively screens off the charge, and in physiologically relevant conditions ~100 millimolar (mM), the characteristic charge screening length (Debye length) is less than a nanometer (nm). Thus, in high ionic strength solutions, charge based (DC) detection is fundamentally impeded6-8.
We overcome charge screening effects by detecting molecular dipoles rather than charges at high frequency, by operating carbon nanotube field effect transistors as high frequency mixers9-11. At high frequencies, the AC drive force can no longer overcome the solution drag and the ions in solution do not have sufficient time to form the EDL. Further, frequency mixing technique allows us to operate at frequencies high enough to overcome ionic screening, and yet detect the sensing signals at lower frequencies11-12. Also, the high transconductance of SWNT transistors provides an internal gain for the sensing signal, which obviates the need for external signal amplifier.
Here, we describe the protocol to (a) fabricate SWNT transistors, (b) functionalize biomolecules to the nanotube13, (c) design and stamp a poly-dimethylsiloxane (PDMS) micro-fluidic chamber14 onto the device, and (d) carry out high frequency sensing in different ionic strength solutions11.

We describe the device fabrication and measurement protocol for carbon nanotube based high frequency biosensors. The high frequency sensing technique mitigates the fundamental ionic (Debye) screening effect and allows nanotube biosensor to be operated in high ionic strength solutions where conventional electronic biosensors fail. Our technology provides a unique platform for point-of-care (POC) electronic biosensors operating in physiologically relevant conditions.

制备碳纳米管高频纳电子生物传感器的传感高离子强度的解决方案

The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) 1-4 make them ...

Fabrication of Flexible Image Sensor Based on Lateral NIPIN Phototransistors

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, but several challenging points remain, such as a low absorption efficiency due to a thin active layer and low flexibility. We present an advanced method to fabricate a flexible phototransistor array with an improved electrical performance. The outstanding electrical performance is driven by a low dark current owing to deep impurity doping. Stretchable and flexible metal interconnectors simultaneously offer electrical and mechanical stabilities in a highly deformed state. The protocol explicitly describes the fabrication process of the phototransistor using a thin silicon membrane. By measuring I-V characteristics of the completed device in deformed states, we demonstrate that this approach improves the mechanical and electrical stabilities of the phototransistor array. We expect that this approach to a flexible phototransistor can be widely used for the applications of not only next-generation imaging systems/optoelectronics but also wearable devices such as tactile/pressure/temperature sensors and health monitors.

We present a detailed method to fabricate a deformable lateral NIPIN phototransistor array for curved image sensors. The phototransistor array with an open mesh form, which is composed of thin silicon islands and stretchable metal interconnectors, provides flexibility and stretchability. The parameter analyzer characterizes the electrical property of the fabricated phototransistor.

基于侧向 NIPIN Phototransistors 的柔性图像传感器的研制

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, ...

Fabrication of Refractive-index-matched Devices for Biomedical Microfluidics

The use of microfluidic devices has emerged as a defining tool for biomedical applications. When combined with modern microscopy techniques, these devices can be implemented as part of a robust platform capable of making simultaneous complementary measurements. The primary challenge created by the combination of these two techniques is the mismatch in refractive index between the materials traditionally used to make microfluidic devices and the aqueous solutions typically used in biomedicine. This mismatch can create optical artifacts near the channel or device edges. One solution is to reduce the refractive index of the material used to fabricate the device by using a fluorinated polymer such as MY133-V2000 whose refractive index is similar to that of water (n = 1.33). Here, the construction of a microfluidic device made out of MY133-V2000 using soft lithography techniques is demonstrated, using O2 plasma in conjunction with an acrylic holder to increase the adhesion between the MY133-V2000 fabricated device and the polydimethylsiloxane (PDMS) substrate. The device is then tested by incubating it filled with cell culture media for 24 h to demonstrate the ability of the device to maintain cell culture conditions during the course of a typical imaging experiment. Finally, quantitative phase microscopy (QPM) is used to measure the distribution of mass within the live adherent cells in the microchannel. This way, the increased precision, enabled by fabricating the device from a low index of refraction polymer such as MY133-V2000 in lieu of traditional soft lithography materials such as PDMS, is demonstrated. Overall, this approach for fabricating microfluidic devices can be readily integrated into existing soft lithography workflows in order to reduce optical artifacts and increase measurement precision.

This protocol describes the fabrication of microfluidic devices from MY133-V2000 to eliminate artifacts that often arise in microchannels due to the mismatching refractive indices between microchannel structures and an aqueous solution. This protocol uses an acrylic holder to compress the encapsulated device, improving adhesion both chemically and mechanically.

生物医学微流体折射率匹配器件的研制

The use of microfluidic devices has emerged as a defining tool for biomedical applications. When combined with modern microscopy techniques, these devices ...

Fully Automated Centrifugal Microfluidic Device for Ultrasensitive Protein Detection from Whole Blood

Enzyme-linked immunosorbent assay (ELISA) is a promising method to detect small amount of proteins in biological samples. The devices providing a platform for reduced sample volume and assay time as well as full automation are required for potential use in point-of-care-diagnostics. Recently, we have demonstrated ultrasensitive detection of serum proteins, C-reactive protein (CRP) and cardiac troponin I (cTnI), utilizing a lab-on-a-disc composed of TiO2 nanofibrous (NF) mats. It showed a large dynamic range with femto molar (fM) detection sensitivity, from a small volume of whole blood in 30 min. The device consists of several components for blood separation, metering, mixing, and washing that are automated for improved sensitivity from low sample volumes. Here, in the video demonstration, we show the experimental protocols and know-how for the fabrication of NFs as well as the disc, their integration and the operation in the following order: processes for preparing TiO2 NF mat; transfer-printing of TiO2 NF mat onto the disc; surface modification for immune-reactions, disc assembly and operation; on-disc detection and representative results for immunoassay. Use of this device enables multiplexed analysis with minimal consumption of samples and reagents. Given the advantages, the device should find use in a wide variety of applications, and prove beneficial in facilitating the analysis of low abundant proteins.

This protocol demonstrates how to achieve femto molar detection sensitivity of proteins in 10 &#181;L of whole blood within 30 min. This can be achieved by using electrospun nanofibrous mats integrated in a lab-on-a-disc, which offers high surface area as well as effective mixing and washing for enhanced signal-to-noise ratio.

全自动离心微流体装置从全血超灵敏蛋白检测

Enzyme-linked immunosorbent assay (ELISA) is a promising method to detect small amount of proteins in biological samples. The devices providing a platform ...

Sensitivity Enhancement of Soft Capacitive Pressure Sensors Using a Solvent Evaporation-Based Porosity Control Technique

Soft pressure sensors play a significant role in developing &#34;man-machine&#34; tactile sensation in soft robotics and haptic interfaces. Specifically, capacitive sensors with micro-structured polymer matrices have been explored with considerable effort because of their high sensitivity, wide linearity range, and fast response time. However, the improvement of the sensing performance often relies on the structural design of the dielectric layer, which requires sophisticated microfabrication facilities. This article reports a simple and low-cost method to fabricate porous capacitive pressure sensors with improved sensitivity using the solvent evaporation-based method to tune the porosity. The sensor consists of a porous polydimethylsiloxane (PDMS) dielectric layer bonded with top and bottom electrodes made of elastic conductive polymer composites (ECPCs). The electrodes were prepared by scrape-coating carbon nanotubes (CNTs)-doped PDMS conductive slurry into mold-patterned PDMS films. To optimize the porosity of the dielectric layer for enhanced sensing performance, the PDMS solution was diluted with toluene of different mass fractions instead of filtering or grinding the sugar pore-forming agent (PFA) into different sizes. The evaporation of the toluene solvent allowed the fast fabrication of a porous dielectric layer with controllable porosities. It was confirmed that the sensitivity could be enhanced more two-fold when the toluene to PDMS ratio was increased from 1:8 to 1:1. The research proposed in this work enables a low-cost method of fabricating fully integrated bionic soft robotic grippers with soft sensory mechanoreceptors of tunable sensor parameters.

A simple and cost-efficient fabrication method based on the solvent evaporation technique is presented to optimize the performance of a soft capacitive pressure sensor, which is enabled by porosity control in the dielectric layer using different mass ratios of the molding PDMS/toluene solution.

基于溶剂蒸发的孔隙率控制技术提高软电容式压力传感器的灵敏度

Soft pressure sensors play a significant role in developing &#34;man-machine&#34; tactile sensation in soft robotics and haptic interfaces. Specifically, ...