Este trabalho foi apoiado pelo programa D de MSIP / IITP (R0190-15-2040, Desenvolvimento de um sistema de gestão de configuração de conteúdo e um simulador para impressão em 3D utilizando materiais inteligentes) a I &amp;.

Atenção: Por favor, consulte todas as normas de segurança pertinentes antes do uso. Vários dos produtos químicos utilizados no fabrico de microchips são altamente tóxicos e cancerígenos. Utilize todas as práticas de segurança adequadas ao executar os processos de fotolitografia e gravura, incluindo o uso de controles de engenharia (extractor de fumo, placa quente, e alinhador) e equipamentos de proteção individual (óculos de segurança, luvas, jaleco, calça de corpo inteiro, e fechou sapatos -toe). 1. Fabricação do microcanal PDMS <ol><li> Fabrico do molde de microcanais pelo processo de fotolito <ol><li> Completamente remover substâncias estranhas na superfície de bolacha de Si a 4 polegadas com limpeza piranha (Figura 1a). Mistura-se ácido sulfúrico (H 2 SO 4) e peróxido de hidrogénio (H 2 O 2) a uma proporção de 3: 1 para tornar a solução piranha no prato. Misturar por adição gradual de pequenas quantidades de ácido forte (H2O <sub&gt; 2) para o ácido fraco (H 2 SO 4); inverter este fim pode provocar uma explosão, porque do ácido forte altamente reactivo. </li><li> Mergulhar a bolacha no piranha solução durante 10 min. Subsequentemente, mergulhar a bolacha em água desionizada (DI) de água durante 3 minutos para remover a solução piranha restante. Lavar a bolacha com fluxo de água DI durante 10 s. Repetir o procedimento de lavagem 3 vezes e seco com gás N2 para remover o restante DI. </li><li> Coloque a bolacha sobre uma placa quente durante 20 minutos a 180 ° C para desidratar ainda mais a bolacha. </li><li> Pour 5 mL do fotorresistente negativo na parte superior da bolacha e rotação revestimento durante 45 s a 1500 rpm (Figura 1b); após revestimento por rotação, um talão de revestimento fotoprotector é criado na borda da bolacha, devido à viscosidade relativamente elevada do material fotosensitivo. </li><li> Equilibre a pastilha revestida-fotorresistente por planarização sobre um suporte de nivelamento durante 5 h. </li><li> Coloque a pastilha revestida de material fotosensitivo sobre uma placa quente durante 12 minutos a 65° C, 35 min a 95 ° C, e 12 min a 65 ° C (cozimento macio). </li><li> Fixar a máscara de película sobre o suporte de máscara e a bolacha mole-cozido na fase substrato do alinhador. Expor à radiação ultravioleta (UV) durante 43 s a 650 mJ / cm 2 para solidificar o material fotosensitivo. </li><li> Coloque a bolacha sobre a placa de aquecimento durante 5 min a 65 ° C, 15 min a 95 ° C e 5 min a 65 ° C (bicarbonato de pós-exposição). </li><li> Mergulhar a bolacha no revelador fotorresistência durante 30 minutos para remover o material fotosensitivo não solidificada. </li><li> Lavar a bolacha com álcool isopropílico (IPA), e seca com gás N2 para remover o IPA restante. </li></ol></li><li> Fabricação do microcanal PDMS <ol><li> Tratar a superfície da bolacha e o molde fotorresistente durante 1 minuto a uma potência de 200 W através de um máquina de plasma atmosférico 25; os fluxos de gás de CH4 e Ele deve ser de 6 e 30 sccm, respectivamente. Realizar este tratamento hidrofóbica para separar facilmente o polydimethylsiloxane (PDMS) microcanal a partir da superfície da pastilha e molde fotorresistente (Figura 1c). </li><li> Preparar a solução de PDMS misturando a base de PDMS e agente de cura, na proporção de 10: 1. Agita-se a mistura durante 2 min. </li><li> Coloque a bolacha no interior de uma placa de Petri (150 mm x 15 mm) e adiciona-se 100 mL da solução de PDMS. Retirar as bolhas que foram criadas a partir de agitação utilizando um exsicador. </li><li> Colocar a placa de Petri no forno durante 2 horas a 80 ° C para solidificar a solução de PDMS (Figura 1d e h). </li><li> Corte ao longo dos contornos do microcanal PDMS com uma lâmina de barbear e retirá-la da bolacha; os microcanais PDMS fabricadas deve ter as seguintes dimensões: 13 mm long, 300 mm de largura, e 150 um de altura (Figuras 1e, f, e i). NOTA: Dois tipos de orifícios são produzidos por um micropunção para inserir a fibra monomodo (SMF) do cabo e os tubos (uma entrada dend tomada) na PDMS microcanal (Figura 1g). O SMF cabo é utilizado para emitir o feixe de laser para a nanohole branqueado na placa de ouro. O tubo é utilizado para inserir / extrair a solução de partículas de / para o microcanal PDMS. </li><li> Punção de entrada de 1,5 mm e furos de saída em cada extremidade do microcanal PDMS. Punção de 0,3 mm SMF orifício do cabo no centro do microcanal PDMS. </li></ol></li></ol> 2. processo de corrosão da placa de ouro <ol><li> Prepara-se uma placa de ouro comercialmente disponível com as dimensões de 25 x 6,25 mm2 (Figura 2a). </li><li> Remover quaisquer substâncias estranhas na placa de ouro com os seguintes procedimentos de limpeza. Limpo na seguinte ordem por imersão em acetona, metanol, e ua DI durante 5 min cada. </li><li> Lavar a placa 3 vezes com ouro ua DI durante 10 s e seca-se a placa com gás N2 para remover a água desionizada remanescente. </li><li> Coloque a placa de ouro em uma placa quente para20 min a 180 ° C, para remover completamente a humidade restante. </li><li> Pour 0,5 ml de hexametildisilazano (HMDS) na placa de ouro e revestimento de centrifugação durante 40 segundos a 3000 rpm. </li><li> Pour 0,5 mL de fotorresistente positiva na parte superior das HMDS revestida por rotação e revestimento de centrifugação durante 40 segundos a 3000 rpm (Figura 2b). </li><li> Colocar a placa de ouro revestidas com material fotosensitivo sobre a placa quente durante 90 s a 110 ° C (cozimento macio). </li><li> Fixar a máscara de filme sobre a pastilha de vidro e colocar a placa de ouro macio-cozido na fase de substrato. Expor à luz UV durante 4,5 s a 64 mJ / cm 2 para dissolver o fotorresistente. </li><li> Imergir a placa de ouro no revelador fotorresistência durante 1 min para remover o material fotosensitivo dissolvido (Figura 2c). Lavar a placa de ouro com água desionizada e seca com N 2 gasoso. </li><li> Imergir a placa de ouro no produto corrosivo de Au por 45 s e a uma velocidade de gravação de 28 Â / s para remover o Au exposto (Figura 2d). Lavar a placa de ouro com águ DIr e seco com N 2 gasoso. </li><li> Imergir a placa de ouro no produto corrosivo Ti durante 5 s e a uma velocidade de gravação de 25 Â / s para remover o Ti exposto (Figura 2E). Lavar a placa de ouro com água desionizada e seca com N 2 gasoso. </li><li> Remover o fotorresistente remanescente na placa de ouro por imersão em acetona, metanol, e ua DI durante 3 min cada (Figura 2f); mergulhe a placa na ordem escrita. </li><li> Lavar a placa 3 vezes com ouro ua DI durante 10 s. Seca com gás N2 para remover a água DI. </li><li> Colocar a placa de ouro sobre a placa quente durante 3 min a 120 ° C, para remover completamente a humidade; o bloco ouro produzida deve ser de 400 x 150? m 2 (figura 2h). </li><li> Moinho um nanohole de 400 nm, utilizando um feixe de iões focado (FIB) no centro do bloco de ouro que foi fabricado após o condicionamento (Figuras 2 g e i). Criar um teste padrão do círculo de 370 nm para se concentrar no bl ouroock com um ião de tensão de aceleração de 30 kV a 28 Pa durante 3 s. </li></ol> 3. Assembleia da Microchip <ol><li> Tratar as duas superfícies do microcanal PDMS e placa de ouro durante 1 min com O2 do plasma para fixá-los em conjunto com um sistema de plasma a uma potência de 80 W e uma pressão de 825 mTorr 25. NOTA: é notavelmente difícil para anexá-los com precisão porque o bloco de ouro e PDMS microcanal estão no nível micrômetro. Assim, usar um alinhador com uma câmara e uma etapa manual. </li><li> Fixar a bolacha de vidro que é usado para fixar a máscara de película para o suporte de máscara do alinhador (Figura 3a). </li><li> Anexar os O-2 tratada -Plasma PDMS microcanal para a pastilha de vidro; porque o PDMS é hidrofílico, ela será facilmente fixar a bolacha de vidro, sem qualquer solução de adesão. Fixar a placa de ouro no substrato de fase o alinhador (Figura 3a). </li><li> Localizar os centros de the SMF orifício do cabo e ouro bloco, que estão alinhados no mesmo eixo, a utilização da câmara no alinhador. Levantar a etapa manual para combinar as duas partes (Figuras 3B e C). </li></ol> 4. Melhoria da rugosidade da superfície Microchip Side by PDMS Coating NOTA: A placa de ouro com dimensões fixas de 400 x 150? M 2 é relativamente mais difícil de cortar para fora do que o material de PDMS. Portanto, para separar o microcanal PDMS a partir da bolacha, uma lâmina de barbear é utilizado para cortar uma peça maior do que a placa de ouro. Depois de combinar as duas partes, as partes excedentes do PDMS em relação à placa de ouro devem então ser cortado de modo a que o interior do canal pode ser observado a partir do lado utilizando um microscópio (Figura 4a). No entanto, a superfície de corte, que é utilizado como uma janela, tem uma rugosidade superficial elevada e, consequentemente, produz imagens nublado das partículas que fluem no canal (Figura4b). Revestimento com a solução PDMS é realizada novamente para resolver esse problema. <ol><li> Preparar a solução de PDMS misturando a base de PDMS e o agente de cura a uma proporção de 10: 1 e agita-se durante 2 min. </li><li> Pour 2 mL da solução de PDMS na placa de Petri e realizar o revestimento por centrifugação durante 30 segundos a 1000 rpm (Figura 4c). </li><li> Coloque a superfície do microchip que vai ser localizado no microscópio sobre a placa de Petri (Figura 4d). Colocar a placa de Petri no forno durante 1 h a 80 ° C para solidificar a solução de PDMS. </li><li> Cortar a borda do microchip e PDMS usando uma lâmina de barbear e, subsequentemente, retirá-la da placa de Petri (Figuras 4e, f). </li></ol> 5. Laser Coupling para inserir o cabo SMF ao Microchip NOTA: Para o sistema de pinça plasmónico, um laser de fibra óptico incidente com um comprimento de onda de 1064-nm é utilizado. O SMF cabo é usado porque o diâmetro da incilaser de dente (5 mm) é também imenso a emitir o feixe de laser no nanohole branqueado no bloco ouro (400 x 150? m 2) na micropastilha. O diâmetro do revestimento do cabo SMF é 125 um. Assim, o laser incidente e cabo SMF deve ser acoplado. <ol><li> Conecte uma lente objetiva de 40X para a objetiva do microscópio montar no acoplador SMF. Fixar o cabo de SMF na braçadeira fibra do acoplador SMF. Alinhar o feixe laser incidente para preencher a abertura de trás da lente objetiva. </li><li> Focar o feixe de laser para o núcleo do cabo SMF, ajustando a fase manual de três eixo equipado no acoplador SMF. </li><li> Inserir a extremidade oposta do cabo de SMF no orifício cabo SMF do microchip. Medir a potência do laser, antes da inserção na extremidade do cabo de fibra, porque o cabo de fibra fixo no microchip não pode ser destacado. </li><li> Vedar o orifício do cabo SMF usando cola epoxi para bloquear o vazamento da solução de partículas que flui a partir do intervalo entre a cabina do SMFle furo (300? m) e o revestimento do cabo SMF (125? m); a extremidade do cabo de fibra inserida não deve entrar no microcanal, para evitar o fluxo de fluido. alinhar manualmente o cabo de fibra usando o feedback visual de modo que seja perpendicular ao bloco ouro que hospeda o nanohole. </li></ol> 6. plasmonic Trapping de Solteiro fluorescente poliestireno partículas na Microchip <ol><li> Anexar a seringa, a qual é preenchida com a solução de partículas, para uma microbomba seringa. Coloque a tampa de vidro no palco amostra do microscópio fluorescente. Conectar tubos para os orifícios de entrada / saída do microchip. Coloque a superfície do microchip PDMS-revestidos no topo do vidro de cobertura. </li><li> Posicionar o microchip ortogonalmente à imersão em água da lente objectiva 60X, observando o interior do canal com a câmara instalada no microscópio fluorescente. Use fita adesiva transparente para fixar o microchip no lugar. Ligar o tubo de entrada do circuito integrado com o ne seringaedle. </li><li> Inserir a solução de partículas para o microchip, controlando a microbomba em 20? M / s. Neste momento, confirmar que a partícula fluorescente pode ser observada bem no canal quando a lâmpada fluorescente está ligado. </li><li> Aguardar até que a solução de partículas sai a partir da saída do circuito integrado. Definir a velocidade de 3.4? M / s. </li><li> Desligue o dispositivo fonte de laser para que ele emite o laser para o nanohole; a partícula fluorescente será preso na borda do nanohole. </li><li> Rampa a velocidade do fluido em incrementos de 0,4? M / s através do controlo da microbomba até que as fugas de partículas retidas. Medir a velocidade do fluido, quando as partículas retidas escapar. Obter a força de captura máxima para cada intensidade do laser utilizando esta velocidade de fluido medido. </li></ol>

<ol>
	<li>Crane, N. B., Onen, O., Carballo, J., Ni, Q., Guldiken, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluidic+assembly+at+the+microscale:+progress+and+prospects.">Fluidic assembly at the microscale: progress and prospects.</a> Microfluid. Nanofluid. 14 (3), 383-419 (2013).</li><li>Yao, B., Luo, G. A., Feng, X., Wang, W., Chen, L. X., Wang, Y. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+microfluidic+device+based+on+gravity+and+electric+force+driving+for+flow+cytometry+and+fluorescence+activated+cell+sorting.">A microfluidic device based on gravity and electric force driving for flow cytometry and fluorescence activated cell sorting.</a> Lab Chip. 4 (6), 603-607 (2004).</li><li>Zhang, K., 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=On-chip+manipulation+of+continuous+picoliter-volume+superparamagnetic+droplets+using+a+magnetic+force.">On-chip manipulation of continuous picoliter-volume superparamagnetic droplets using a magnetic force.</a> Lab Chip. 9 (20), 2992-2999 (2009).</li><li>Park, I. Y., Sung, S. Y., Lee, J. H., Lee, Y. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Manufacturing+micro-scale+structures+by+an+optical+tweezers+system+controlled+by+five+finger+tips.">Manufacturing micro-scale structures by an optical tweezers system controlled by five finger tips.</a> J. Micromech. Microeng. 17, N82-N89 (2007).</li><li>Kim, J. D., Hwang, S. U., Lee, Y. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Traceable+assembly+of+microparts+using+optical+tweezers.">Traceable assembly of microparts using optical tweezers.</a> J. Micromech. Microeng. 22, 105003 (2012).</li><li>Kim, J. D., Lee, Y. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Construction+and+actuation+of+a+microscopic+gear+assembly+formed+using+optical+tweezers.">Construction and actuation of a microscopic gear assembly formed using optical tweezers.</a> J. Micromech. Microeng. 23, 065010 (2013).</li><li>Kim, J. D., Choi, J. H., Lee, Y. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+measurement+of+the+maximal+forces+in+plasmonic+tweezers.">A measurement of the maximal forces in plasmonic tweezers.</a> Nanotechnology. 26 (42), 425203 (2015).</li><li>Kim, J. D., Lee, Y. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trapping+of+a+single+DNA+molecule+using+nanoplasmonic+structures+for+biosensor+applications.">Trapping of a single DNA molecule using nanoplasmonic structures for biosensor applications.</a> Biomed. Opt. Express. 5 (8), 2471-2480 (2014).</li><li>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=Plasmonic+tweezers+-+the+strength+of+surface+plasmons.">Plasmonic tweezers - the strength of surface plasmons.</a> MRS Bull. 37 (8), 739-744 (2012).</li><li>Juan, M. L., Gordon, R., Pang, Y., Eftekhari, F., 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=Self-induced+back-action+optical+trapping+of+dielectric+nanoparticles.">Self-induced back-action optical trapping of dielectric nanoparticles.</a> Nat. Phys. 5, 915-919 (2009).</li><li>Pang, Y., Gordon, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+trapping+of+12+nm+dielectric+spheres+using+double-nanoholes+in+a+gold+film.">Optical trapping of 12 nm dielectric spheres using double-nanoholes in a gold film.</a> Nano Lett. 11 (9), 3763-3767 (2011).</li><li>Tanaka, Y., Kaneda, S., Sasaki, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanostructured+potential+of+optical+trapping+using+a+plasmonic+nanoblock+pair.">Nanostructured potential of optical trapping using a plasmonic nanoblock pair.</a> Nano Lett. 13 (5), 2146-2150 (2013).</li><li>Kang, J. 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=Low-power+nano-optical+vortex+trapping+via+plasmonic+diabolo+nanoantennas.">Low-power nano-optical vortex trapping via plasmonic diabolo nanoantennas.</a> Nat. Commun. 2, 582 (2011).</li><li>Roxworthy, B. 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=Application+of+plasmonic+bowtie+nanoantenna+arrays+for+optical+trapping,+stacking,+and+sorting.">Application of plasmonic bowtie nanoantenna arrays for optical trapping, stacking, and sorting.</a> Nano Lett. 12 (2), 796-801 (2012).</li><li>Shoji, T., Tsuboi, 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+optical+tweezers+toward+molecular+manipulation:+tailoring+plasmonic+nanostructure,+light+source,+and+resonant+trapping.">Plasmonic optical tweezers toward molecular manipulation: tailoring plasmonic nanostructure, light source, and resonant trapping.</a> J. Phys. Chem. Lett. 5 (17), 2957-2967 (2014).</li><li>Pang, Y., Gordon, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+trapping+of+a+single+protein.">Optical trapping of a single protein.</a> Nano Lett. 12 (1), 402-406 (2012).</li><li>Tsuboi, 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=Optical+trapping+of+quantum+dots+based+on+gap-mode-excitation+of+localized+surface+plasmon.">Optical trapping of quantum dots based on gap-mode-excitation of localized surface plasmon.</a> J. Phys. Chem. Lett. 1, 2327-2333 (2010).</li><li>Shoji, T., 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=Permanent+fixing+or+reversible+trapping+and+release+of+DNA+micropatterns+on+a+gold+nanostructure+using+continuous-wave+or+femtosecond-pulsed+near-infrared+laser+light.">Permanent fixing or reversible trapping and release of DNA micropatterns on a gold nanostructure using continuous-wave or femtosecond-pulsed near-infrared laser light.</a> J. Am. Chem. Soc. 135 (17), 6643-6648 (2013).</li><li>Grigrenko, A. N., Roberts, N. W., Dickson, M. R., Zhang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanometric+optical+tweezers+based+on+nanostructured+substrates.">Nanometric optical tweezers based on nanostructured substrates.</a> Nat. Photonics. 2, 365-370 (2008).</li><li>Righini, 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=Nano-optical+trapping+of+rayleigh+particles+and+escherichia+coli+bacteria+with+resonant+optical+antennas.">Nano-optical trapping of rayleigh particles and escherichia coli bacteria with resonant optical antennas.</a> Nano Lett. 9 (10), 3387-3391 (2009).</li><li>Chen, K. Y., Lee, A. T., Hung, C. C., Huang, J. S., Yang, Y. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transport+and+trapping+in+two-dimensional+nanoscale+plasmonic+optical+lattice.">Transport and trapping in two-dimensional nanoscale plasmonic optical lattice.</a> Nano Lett. 13 (9), 4118-4122 (2013).</li><li>Berthelot, 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=Three-dimensional+manipulation+with+scanning+near-field+optical+nanotweezers.">Three-dimensional manipulation with scanning near-field optical nanotweezers.</a> Nat. Nanotechnol. 9 (4), 295-299 (2014).</li><li>Chen, 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=Enhanced+optical+trapping+and+arrangement+of+nano-objects+in+a+plasmonic+nanocavity.">Enhanced optical trapping and arrangement of nano-objects in a plasmonic nanocavity.</a> Nano Lett. 12 (1), 125-132 (2011).</li><li>Wang, K., Schonbrun, E., Steinvurzel, P., Crozier, K. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trapping+and+rotating+nanoparticles+using+a+plasmonic+nano-tweezer+with+an+integrated+heat+sink.">Trapping and rotating nanoparticles using a plasmonic nano-tweezer with an integrated heat sink.</a> Nat. Commun. 2, 469 (2011).</li><li>Byun, D., Cho, S. J., Kim, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+a+flexible+penetrating+microelectrode+array+for+use+on+curved+surfaces+of+neural+tissues.">Fabrication of a flexible penetrating microelectrode array for use on curved surfaces of neural tissues.</a> J. Micromech. Microeng. 23, 125010 (2013).</li></ol>

Os autores não têm nada a revelar.

O cabo SMF foi inserida no orifício do cabo de SMF no circuito integrado, tal como mostrado no ponto rectangular da Figura 6a. Uma vez que o orifício do cabo SMF é maior do que o diâmetro do cabo, cola epóxi foi usado para selar a abertura para bloquear o vazamento da solução de partículas que flui. Antes da aplicação da cola epoxi, o bloco ouro e borda cabo deve ser alinhado coaxialmente à mão usando um microscópio. Embora seja ideal para a extremidade do cabo inserido e o nanohole para se...

A capacidade para manipular objectos microescala é uma característica indispensável para muitas experiências de micro / nano. manipulações de contacto directo pode danificar os objectos manipulados. Liberando os objetos anteriormente detidas também é um desafio por causa de problemas stiction. Para ultrapassar estes problemas, vários métodos indirectos usando fluídica 1, 2 eléctrico, magnético 3, ou forças fotónicas 4, 5, 6, 7, 8, têm sido propostos. Pinças plasmonic que usam forças fotônicos são baseados na física de extraordinárias realce campo várias ordens maiores do que a intensidade incidente 9. Este melhoramento campo extremamente forte permite que o aprisionamento de nanopartículas extremamente pequenas. Por exemplo, tem sido demonstrado para imobilizar e manipular nanoescalaobjectos, tais como partículas de poliestireno 7, 10, 11, 12, 13, 14, 15 cadeias de polímeros, proteínas 16, quantum dots 17, e as moléculas de ADN 8, 18. Sem pinças plasmonic, é difícil para as nanopartículas de armadilha porque eles desaparecem rapidamente antes de serem eficazmente examinados ou porque elas são danificadas devido à alta intensidade do laser. Muitos estudos plasmonic têm usado várias estruturas de ouro em nanoescala. Podemos categorizar as estruturas de ouro como saliente tipos nanodisk 12, 13, 14, 15, 19 <s-se&gt;, 20, 21 ou suprimidos tipos nanohole 7, 8, 10, 11, 22, 23. Em termos de conveniência de imagiologia, os tipos nanodisk são mais adequados do que os tipos nanohole porque, para estes últimos, os substratos de ouro podem obstruir a vista de observação. Além disso, a retenção ocorre plasmónico perto da estrutura plasmónico e faz observação ainda mais difícil. Para o melhor de nosso conhecimento, trapping plasmonic em tipos nanohole só foi verificada através de sinais de espalhamento indiretos. No entanto, há observações diretas de sucesso, como imagens microscópicas, foram relatados. Alguns estudos têm descrito a posição de partículas retidas. Um tal resultado foi apresentado por Wang et al. Eles criaram um pilar de ouro sobre um substrato de ouro e observou o partigo movimento utilizando um microscópio de fluorescência 24. No entanto, isto só é eficaz para monitorizar os movimentos laterais não na direcção paralela ao eixo do feixe. Neste artigo, apresentamos novos procedimentos de design microchip e fabricação fluídicos. Usando este chip, que demonstram o controlo de partículas plasmonically presos, tanto em direcções paralelas e ortogonais ao nanoestrutura plasmónico. Além disso, nós medimos a força máxima da partícula imobilizada através do aumento da velocidade do fluido para encontrar a velocidade de inflexão no microchip. Este estudo é único porque a maioria dos estudos sobre pinças plasmonic não pode mostrar quantitativamente as forças de captura máximos utilizados nas respectivas montagens experimentais.

<table><tbody><tr><td>Negative photoresist&amp;nbsp;</td><td>MicroChem</td><td>SU-8 2075</td><td></td></tr><tr><td>Developer</td><td>MicroChem</td><td>SU-8 Developer</td><td></td></tr><tr><td>Positive photoresist&amp;nbsp;</td><td>Merck Ltd.</td><td>AZ GXR-601</td><td></td></tr><tr><td>AZ Photoresist Developers</td><td>Merck Ltd.</td><td>AZ 300 MIF</td><td></td></tr><tr><td>HMDS</td><td>Merck Ltd.</td><td>AZ Adhesion Promoter</td><td></td></tr><tr><td>Aligner</td><td>Midas System</td><td>MDA 400M</td><td></td></tr><tr><td>Atmospheric plasma machine&amp;nbsp;</td><td>Atmospheric Process&lt;br/&gt; Plasma Co.</td><td>IDP-1000</td><td></td></tr><tr><td>Polydimethylsiloxane (PDMS)</td><td>Dow Corning</td><td>Sylgard 184 A/B</td><td></td></tr><tr><td>Gold coated test slides</td><td>EMF Co.</td><td>TA124(Ti/Au)</td><td></td></tr><tr><td>Au etchant&amp;nbsp;</td><td>Transene Inc.</td><td>TFA</td><td></td></tr><tr><td>Ti etchant&amp;nbsp;</td><td>Transene Inc.</td><td>TFT</td><td></td></tr><tr><td>40X objective lens&amp;nbsp;</td><td>Edmund Optics</td><td>40X DIN</td><td></td></tr><tr><td>60X water immersion&lt;br/&gt; objective lens&amp;nbsp;</td><td>Olympus</td><td>LUMPLFLN 60XW</td><td></td></tr><tr><td>Optical fiber incident laser&amp;nbsp;</td><td>IPG Photonic</td><td>YLR 10</td><td></td></tr><tr><td>SMF coupler</td><td>Thorlabs</td><td>MBT612D/M</td><td></td></tr><tr><td>Syringe micropump</td><td>Harvard</td><td>PC2 70-4501</td><td></td></tr><tr><td>Fluorescent microscope&amp;nbsp;</td><td>Olympus</td><td>IX-51</td><td></td></tr><tr><td>Plasma system</td><td>Femto Science Inc</td><td>CUTE-MPR</td><td></td></tr></tbody></table>

plasmonic trapping and release of nanoparticles in a monitoring environment

pinças plasmonic usar polaritons plasmon de superfície para confinar objetos em nanoescala polarizáveis. Entre os vários modelos de pinças plasmonic, apenas algumas partículas podem observar imobilizadas. Além disso, um número limitado de estudos têm medido experimentalmente as forças exertable sobre as partículas. Os desenhos podem ser classificadas como do tipo nanodisk saliente ou do tipo nanohole suprimida. Para este último, a observação microscópica é extremamente desafiador. Neste trabalho, um novo sistema de pinça plasmónico é introduzida para monitorizar partículas, tanto em direcções paralelas e ortogonais ao eixo de simetria de uma estrutura nanohole plasmónico. Este recurso permite-nos observar o movimento de cada partícula perto da borda do nanohole. Além disso, podemos estimar quantitativamente as forças de captura máximos, utilizando um novo canal fluídico.

O processo de fabricação do microcanal e ouro nanohole placa PDMS é mostrado nas Figuras 1 e 2. O método de combinar as duas partes e o microchip real é mostrada na Figura 3. O PDMS foi cortada para revelar o interior do canal a partir do lado da micropastilha. No entanto, foi difícil de observar as partículas que fluem no canal, devido à rugosidade da superfície do plano de corte. Assim, introduzimos o método de revestimento P...

Watch this Scientific Journal Video about Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment at JoVE.com

Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment

Um processo de fabricação microchip, que incorpora uma pinça plasmonic é apresentado aqui. O microchip permite a imagiologia de uma partícula preso para medir as forças máximas de armadilhagem.

Plasmonic captura e liberação de nanopartículas em um ambiente de Monitoramento

Plasmonic tweezers use surface plasmon polaritons to confine polarizable nanoscale objects. Among the various designs of plasmonic tweezers, only a few ...

plasmonic-trapping-release-nanoparticles-monitoring

Research

JoVE Journal

Engineering

7.5K visualizações.  Korea Basic Science Institute (KBSI).  Um processo de fabricação microchip, que incorpora uma pinça plasmonic é apresentado aqui. O microchip permite a imagiologia de uma partícula preso para medir as forças máximas de armadilhagem. 

Vídeo: Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment

Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To compensate for lower light absorption such physically thin devices have to incorporate light-trapping which increases their optical thickness. Light scattering by textured surfaces is a common technique but it cannot be universally applied to all solar cell technologies. Some cells, for example those made of evaporated silicon, are planar as produced and they require an alternative light-trapping means suitable for planar devices. Metal nanoparticles formed on planar silicon cell surface and capable of light scattering due to surface plasmon resonance is an effective approach.
The paper presents a fabrication procedure of evaporated polycrystalline silicon solar cells with plasmonic light-trapping and demonstrates how the cell quantum efficiency improves due to presence of metal nanoparticles.
To fabricate the cells a film consisting of alternative boron and phosphorous doped silicon layers is deposited on glass substrate by electron beam evaporation. An Initially amorphous film is crystallised and electronic defects are mitigated by annealing and hydrogen passivation. Metal grid contacts are applied to the layers of opposite polarity to extract electricity generated by the cell. Typically, such a ~2 &mu;m thick cell has a short-circuit current density (Jsc) of 14-16 mA/cm2, which can be increased up to 17-18 mA/cm2 (~25% higher) after application of a simple diffuse back reflector made of a white paint.
To implement plasmonic light-trapping a silver nanoparticle array is formed on the metallised cell silicon surface. A precursor silver film is deposited on the cell by thermal evaporation and annealed at 23&deg;C to form silver nanoparticles. Nanoparticle size and coverage, which affect plasmonic light-scattering, can be tuned for enhanced cell performance by varying the precursor film thickness and its annealing conditions. An optimised nanoparticle array alone results in cell Jsc enhancement of about 28%, similar to the effect of the diffuse reflector. The photocurrent can be further increased by coating the nanoparticles by a low refractive index dielectric, like MgF2, and applying the diffused reflector. The complete plasmonic cell structure comprises the polycrystalline silicon film, a silver nanoparticle array, a layer of MgF2, and a diffuse reflector. The Jsc for such cell is 21-23 mA/cm2, up to 45% higher than Jsc of the original cell without light-trapping or ~25% higher than Jsc for the cell with the diffuse reflector only.
Introduction
Light-trapping in silicon solar cells is commonly achieved via light scattering at textured interfaces. Scattered light travels through a cell at oblique angles for a longer distance and when such angles exceed the critical angle at the cell interfaces the light is permanently trapped in the cell by total internal reflection (Animation 1: Light-trapping). Although this scheme works well for most solar cells, there are developing technologies where ultra-thin Si layers are produced planar (e.g. layer-transfer technologies and epitaxial c-Si layers) 1 and or when such layers are not compatible with textures substrates (e.g. evaporated silicon) 2. For such originally planar Si layer alternative light trapping approaches, such as diffuse white paint reflector 3, silicon plasma texturing 4 or high refractive index nanoparticle reflector 5 have been suggested.
Metal nanoparticles can effectively scatter incident light into a higher refractive index material, like silicon, due to the surface plasmon resonance effect 6. They also can be easily formed on the planar silicon cell surface thus offering a light-trapping approach alternative to texturing. For a nanoparticle located at the air-silicon interface the scattered light fraction coupled into silicon exceeds 95% and a large faction of that light is scattered at angles above critical providing nearly ideal light-trapping condition (Animation 2: Plasmons on NP). The resonance can be tuned to the wavelength region, which is most important for a particular cell material and design, by varying the nanoparticle average size, surface coverage and local dielectric environment 6,7. Theoretical design principles of plasmonic nanoparticle solar cells have been suggested 8. In practice, Ag nanoparticle array is an ideal light-trapping partner for poly-Si thin-film solar cells because most of these design principle are naturally met. The simplest way of forming nanoparticles by thermal annealing of a thin precursor Ag film results in a random array with a relatively wide size and shape distribution, which is particularly suitable for light-trapping because such an array has a wide resonance peak, covering the wavelength range of 700-900 nm, important for poly-Si solar cell performance. The nanoparticle array can only be located on the rear poly-Si cell surface thus avoiding destructive interference between incident and scattered light which occurs for front-located nanoparticles 9. Moreover, poly-Si thin-film cells do not requires a passivating layer and the flat base-shaped nanoparticles (that naturally result from thermal annealing of a metal film) can be directly placed on silicon further increases plasmonic scattering efficiency due to surface plasmon-polariton resonance 10.
The cell with the plasmonic nanoparticle array as described above can have a photocurrent about 28% higher than the original cell. However, the array still transmits a significant amount of light which escapes through the rear of the cell and does not contribute into the current. This loss can be mitigated by adding a rear reflector to allow catching transmitted light and re-directing it back to the cell. Providing sufficient distance between the reflector and the nanoparticles (a few hundred nanometers) the reflected light will then experience one more plasmonic scattering event while passing through the nanoparticle array on re-entering the cell and the reflector itself can be made diffuse - both effects further facilitating light scattering and hence light-trapping. Importantly, the Ag nanoparticles have to be encapsulated with an inert and low refractive index dielectric, like MgF2 or SiO2, from the rear reflector to avoid mechanical and chemical damage 7. Low refractive index for this cladding layer is required to maintain a high coupling fraction into silicon and larger scattering angles, which are ensured by the high optical contrast between the media on both sides of the nanoparticle, silicon and dielectric 6. The photocurrent of the plasmonic cell with the diffuse rear reflector can be up to 45% higher than the current of the original cell or up to 25% higher than the current of an equivalent cell with the diffuse reflector only.

Polycrystalline silicon thin-film solar cells on glass are fabricated by deposition of boron and phosphorous doped silicon layers followed by crystallisation, defect passivation and metallisation. Plasmonic light-trapping is introduced by forming Ag nanoparticles on the silicon cell surface capped with a diffused reflector resulting in ~45% photocurrent enhancement.

Silício policristalino de película fina de células solares com plasmonic avançada Luz-caça com armadilhas

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To ...

Engenharia

Optical Trapping of Nanoparticles

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping and manipulating small biological particles. Ashkin and co-workers first demonstrated optical tweezers using a single focused beam1. The single beam trap can be described accurately using the perturbative gradient force formulation in the case of small Rayleigh regime particles1. In the perturbative regime, the optical power required for trapping a particle scales as the inverse fourth power of the particle size. High optical powers can damage dielectric particles and cause heating. For instance, trapped latex spheres of 109 nm in diameter were destroyed by a 15 mW beam in 25 sec1, which has serious implications for biological matter2,3.
A self-induced back-action (SIBA) optical trapping was proposed to trap 50 nm polystyrene spheres in the non-perturbative regime4. In a non-perturbative regime, even a small particle with little permittivity contrast to the background can influence significantly the ambient electromagnetic field and induce a large optical force. As a particle enters an illuminated aperture, light transmission increases dramatically because of dielectric loading. If the particle attempts to leave the aperture, decreased transmission causes a change in momentum outwards from the hole and, by Newton's Third Law, results in a force on the particle inwards into the hole, trapping the particle. The light transmission can be monitored; hence, the trap can become a sensor. The SIBA trapping technique can be further improved by using a double-nanohole structure.
The double-nanohole structure has been shown to give a strong local field enhancement5,6. Between the two sharp tips of the double-nanohole, a small particle can cause a large change in optical transmission, thereby inducing a large optical force. As a result, smaller nanoparticles can be trapped, such as 12 nm silicate spheres7 and 3.4 nm hydrodynamic radius bovine serum albumin proteins8. In this work, the experimental configuration used for nanoparticle trapping is outlined. First, we detail the assembly of the trapping setup which is based on a Thorlabs Optical Tweezer Kit. Next, we explain the nanofabrication procedure of the double-nanohole in a metal film, the fabrication of the microfluidic chamber and the sample preparation. Finally, we detail the data acquisition procedure and provide typical results for trapping 20 nm polystyrene nanospheres.

The following setup approach details low power optical trapping of dielectric nanoparticles using a double-nanohole in metal film.

Captura óptica de nanopartículas

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping ...

Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities

High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular organelles 2,3, as well as for high spatial and temporal resolution readout of their position relative to the center of the trap. The system described herein has one such "traditional" trap operating at 980 nm. It additionally provides a second optical trapping system that uses a commercially available holographic package to simultaneously create and manipulate complex trapping patterns in the field of view of the microscope 4,5 at a wavelength of 1,064 nm. The combination of the two systems allows for the manipulation of multiple refractive objects at the same time while simultaneously conducting high speed and high resolution measurements of motion and force production at nanometer and piconewton scale.

The system described herein employs a traditional optical trap as well as an independent holographic optical trapping line, capable of creating and manipulating multiple traps. This allows for the creation of complex geometric arrangements of refractive particles while also permitting simultaneous high-speed, high-resolution measurements of the activity of biological enzymes.

Construção de um microscópio de alta resolução com recursos de captura óptica convencional e holográfico

High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular ...

Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation

A method to manipulate the position and orientation of submicron particles nondestructively would be an incredibly useful tool for basic biological research. Perhaps the most widely used physical force to achieve noninvasive manipulation of small particles has been dielectrophoresis(DEP).1 However, DEP on its own lacks the versatility and precision that are desired when manipulating cells since it is traditionally done with stationary electrodes. Optical tweezers, which utilize a three dimensional electromagnetic field gradient to exert forces on small particles, achieve this desired versatility and precision.2 However, a major drawback of this approach is the high radiation intensity required to achieve the necessary force to trap a particle which can damage biological samples.3 A solution that allows trapping and sorting with lower optical intensities are optoelectronic tweezers (OET) but OET's have limitations with fine manipulation of small particles; being DEP-based technology also puts constraint on the property of the solution.4,5
This video article will describe two methods that decrease the intensity of the radiation needed for optical manipulation of living cells and also describe a method for orientation control. The first method is plasmonic tweezers which use a random gold nanoparticle (AuNP) array as a substrate for the sample as shown in Figure 1. The AuNP array converts the incident photons into localized surface plasmons (LSP) which consist of resonant dipole moments that radiate and generate a patterned radiation field with a large gradient in the cell solution. Initial work on surface plasmon enhanced trapping by Righini et al and our own modeling have shown the fields generated by the plasmonic substrate reduce the initial intensity required by enhancing the gradient field that traps the particle.6,7,8 The plasmonic approach allows for fine orientation control of ellipsoidal particles and cells with low optical intensities because of more efficient optical energy conversion into mechanical energy and a dipole-dependent radiation field. These fields are shown in figure 2 and the low trapping intensities are detailed in figures 4 and 5. The main problems with plasmonic tweezers are that the LSP's generate a considerable amount of heat and the trapping is only two dimensional. This heat generates convective flows and thermophoresis which can be powerful enough to expel submicron particles from the trap.9,10 The second approach that we will describe is utilizing periodic dielectric nanostructures to scatter incident light very efficiently into diffraction modes, as shown in figure 6.11 Ideally, one would make this structure out of a dielectric material to avoid the same heating problems experienced with the plasmonic tweezers but in our approach an aluminum-coated diffraction grating is used as a one-dimensional periodic dielectric nanostructure. Although it is not a semiconductor, it did not experience significant heating and effectively trapped small particles with low trapping intensities, as shown in figure 7. Alignment of particles with the grating substrate conceptually validates the proposition that a 2-D photonic crystal could allow precise rotation of non-spherical micron sized particles.10 The efficiencies of these optical traps are increased due to the enhanced fields produced by the nanostructures described in this paper.

Plasmonic tweezers and photonic crystal nanostructures are shown to produce useful enhancements in the efficiency and orientation control of optically trapping micro- and nano-particles.

Utilização de Nanoestruturas Cristal plasmônicos e Fotônica para Manipulação de Micro-e Nanopartículas melhorada

A method to manipulate the position and orientation of submicron particles nondestructively would be an incredibly useful tool for basic biological ...

Bioengenharia

Analyzing the Movement of the Nauplius 'Artemia salina' by Optical Tracking of Plasmonic Nanoparticles

We demonstrate how optical tweezers may provide a sensitive tool to analyze the fluidic vibrations generated by the movement of small aquatic organisms. A single gold nanoparticle held by an optical tweezer is used as a sensor to quantify the rhythmic motion of a Nauplius larva (Artemia salina) in a water sample. This is achieved by monitoring the time dependent displacement of the trapped nanoparticle as a consequence of the Nauplius activity. A Fourier analysis of the nanoparticle&#39;s position then yields a frequency spectrum that is characteristic to the motion of the observed species. This experiment demonstrates the capability of this method to measure and characterize the activity of small aquatic larvae without the requirement to observe them directly and to gain information about the position of the larvae with respect to the trapped particle. Overall, this approach could give an insight on the vitality of certain species found in an aquatic ecosystem and could expand the range of conventional methods for analyzing water samples.

Analyzing the Movement of the Nauplius 'Artemia salina' by Optical Tracking of Plasmonic Nanoparticles

We use optical tracking of plasmonic nanoparticles to probe and characterize the frequency movements of aquatic organisms.

Analisando o movimento da Nauplius &#39;<em&gt; Artemia salina</em&gt; &#39;Por Optical Rastreamento de plasmônicos Nanopartículas

We demonstrate how optical tweezers may provide a sensitive tool to analyze the fluidic vibrations generated by the movement of small aquatic organisms. A ...

Fabrication and Operation of a Nano-Optical Conveyor Belt

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological and physical sciences over the past few decades. The progress made in this field invites further study of even smaller systems and at a larger scale, with tools that could be distributed more easily and made more widely available. Unfortunately, the fundamental laws of diffraction limit the minimum size of the focal spot of a laser beam, which makes particles smaller than a half-wavelength in diameter hard to trap and generally prevents an operator from discriminating between particles which are closer together than one half-wavelength. This precludes the optical manipulation of many closely-spaced nanoparticles and&#160;limits the&#160;resolution of optical-mechanical systems. Furthermore, manipulation using focused beams requires beam-forming or steering optics, which can be very bulky and expensive. To address these limitations in the system scalability of conventional optical trapping our lab has devised an alternative technique which utilizes near-field optics to move particles across a chip. Instead of focusing laser beams in the far-field, the optical near field of plasmonic resonators produces the necessary local optical intensity enhancement to overcome the restrictions of diffraction and manipulate particles at higher resolution. Closely-spaced resonators produce strong optical traps which can be addressed to mediate the hand-off of particles from one to the next in a conveyor-belt-like fashion. Here, we describe how to design and produce a conveyor belt using a gold surface patterned with plasmonic C-shaped resonators and how to operate it with polarized laser light to achieve super-resolution nanoparticle manipulation and transport. The nano-optical conveyor belt chip can be produced using lithography techniques and easily packaged and distributed.

The scalability and resolution of conventional optical manipulation techniques are limited by diffraction. We circumvent the diffraction limit and describe a method of optically transporting nanoparticles across a chip using a gold surface patterned with a path of closely spaced C-shaped plasmonic resonators.

Fabricação e operação de uma Correia Transportadora Nano-óptica

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological ...

Construction and Operation of a Light-driven Gold Nanorod Rotary Motor System

The possibility to generate and measure rotation and torque at the nanoscale is of fundamental interest to the study and application of biological and artificial nanomotors and may provide new routes towards single cell analysis, studies of non-equilibrium thermodynamics, and mechanical actuation of nanoscale systems. A facile way to drive rotation is to use focused circularly polarized laser light in optical tweezers. Using this approach, metallic nanoparticles can be operated as highly efficient scattering-driven rotary motors spinning at unprecedented rotation frequencies in water.
In this protocol, we outline the construction and operation of circularly-polarized optical tweezers for nanoparticle rotation and describe the instrumentation needed for recording the Brownian dynamics and Rayleigh scattering of the trapped particle. The rotational motion and the scattering spectra provides independent information on the properties of the nanoparticle and its immediate environment. The experimental platform has proven useful as a nanoscopic gauge of viscosity and local temperature, for tracking morphological changes of nanorods and molecular coatings, and as a transducer and probe of photothermal and thermodynamic processes.

Plasmonic gold nanorods can be trapped in liquids and rotated at kHz frequencies using circularly-polarized optical tweezers. Introducing tools for Brownian dynamics analysis and light scatteringspectroscopy leads to a powerful system for research and application in numerous fields of science.

Construção e operação de um sistema de Motor controlado por luz ouro Nanorod Rotary

The possibility to generate and measure rotation and torque at the nanoscale is of fundamental interest to the study and application of biological and ...

Trapping of Micro Particles in Nanoplasmonic Optical Lattice

The plasmonic optical tweezer has been developed to overcome the diffraction limits of the conventional far field optical tweezer. Plasmonic optical lattice consists of an array of nanostructures, which exhibit a variety of trapping and transport behaviors. We report the experimental procedures to trap micro-particles in a simple square nanoplasmonic optical lattice. We also describe the optical setup and the nanofabrication of a nanoplasmonic array. The optical potential is created by illuminating an array of gold nanodiscs with a Gaussian beam of 980 nm wavelength, and exciting plasmon resonance. The motion of particles is monitored by fluorescence imaging. A scheme to suppress photothermal convection is also described to increase usable optical power for optimal trapping. Suppression of convection is achieved by cooling the sample to a low temperature, and utilizing the near-zero thermal expansion coefficient of a water medium. Both single particle transport and multiple particle trapping are reported here.

We describe a procedure to optically trap micro-particles in nanoplasmonic optical lattice.

Captura de Micro partículas em Lattice ótico Nanoplasmonic

The plasmonic optical tweezer has been developed to overcome the diffraction limits of the conventional far field optical tweezer. Plasmonic optical ...

Monitoring Conformational Dynamics of Single Unmodified Proteins using Plasmonic Nanotweezers

Current single-molecule techniques to characterize proteins typically require labels, tethers, or the use of non-native solution conditions. Such changes can alter protein biophysics and reduce the usefulness of the data acquired. Plasmonic nanotweezers is a technique that uses localized surface plasmon resonance (LSPR) on gold nanostructures to enhance the electric field within a confined hotspot region. This field enhancement allows for the use of low laser powers to trap single nanoparticles far smaller than conventional optical tweezers, down to only a few nanometers in diameter, such as single proteins. Trapping of single protein molecules within the hotspot region induces a shift in the local refractive index (nprotein &#62; nwater), altering light scattering as a product of the molecule&#39;s polarisability, which is affected by its volume, shape anisotropy, and refractive index. An avalanche photodiode (APD) collects the subsequent changes in light scattering. These alterations can then be analyzed to determine changes in the trapped molecule, including its size, global conformation, and dynamics of conformational change over time. The incorporation of microfluidics within the system allows for controlled environmental changes and real-time monitoring of their subsequent effects on the molecule. In this protocol, we demonstrate the steps to trap single protein molecules, alter their environmental solution conditions, and monitor their corresponding conformational changes using a plasmonic nanotweezers system.

Plasmonic nanotweezers use localized surface plasmon resonance in gold nanostructures to trap single nanoparticles, including proteins, within a nanometer-scale optical field. Changes in the scattered signal reveal protein presence and conformational dynamics, enabling monitoring without fluorophore modifications or surface tethering.

Monitoramento da dinâmica conformacional de proteínas únicas não modificadas usando pinças plasmônicas

Current single-molecule techniques to characterize proteins typically require labels, tethers, or the use of non-native solution conditions. Such changes ...

Optical Trapping of Plasmonic Nanoparticles for In Situ Surface-Enhanced Raman Spectroscopy Characterizations

Surface-enhanced Raman spectroscopy (SERS) enables the ultrasensitive detection of analyte molecules in various applications due to the enhanced electric field of metallic nanostructures. Salt-induced silver nanoparticle aggregation is the most popular method for generating SERS-active substrates; however, it is limited by poor reproducibility, stability, and biocompatibility. The present protocol integrates optical manipulation and SERS detection to develop an efficient analytical platform to address this. A 1064 nm trapping laser and a 532 nm Raman probe laser are combined in a microscope to assemble silver nanoparticles, which generate plasmonic hotspots for in situ SERS measurements in aqueous environments. Without aggregating agents, this dynamic plasmonic silver nanoparticle assembly enables an approximately 50-fold enhancement of the analyte molecule signal. Moreover, it provides spatial and temporal control to form the SERS-active assembly in as low as 0.05 nM analyte-coated silver nanoparticle solution, which minimizes the potential perturbation for in vivo analysis. Hence, this optical trapping-integrated SERS platform holds great potential for efficient, reproducible, and stable molecular analyses in liquids, especially in aqueous physiological environments.

Optical Trapping of Plasmonic Nanoparticles for In Situ Surface-Enhanced Raman Spectroscopy Characterizations

The present protocol describes a convenient approach to integrating optical trapping and surface-enhanced Raman spectroscopy (SERS) to manipulate plasmonic nanoparticles for sensitive molecular detection. Without aggregating agents, the trapping laser assembles plasmonic nanoparticles to enhance the SERS signals of target analytes for in situ spectroscopic measurements.

Captura óptica de nanopartículas plasmônicas para caracterizações de espectroscopia raman aprimoradas na superfície de Situ

Surface-enhanced Raman spectroscopy (SERS) enables the ultrasensitive detection of analyte molecules in various applications due to the enhanced electric ...