Temos sem agradecimentos.

Atenção: Por favor, vestir um jaleco, luvas e óculos de segurança e ler fichas de dados de segurança (MSDS) antes do uso. Todos os materiais comprados foram usados sem mais purificação.
1. preparação de emulsões, constituídos por misturas de solução SDS estireno/PFO/aquoso
<ol><li>Para preparar a 5 mM de solução aquosa de SDS, dissolver 14,5 mg de SDS em 10 mL de alta pureza H2O. Nota: Tem sido usado de alta pureza H2O (resistividade (R) = 18 cm MΩ, tensão superficial (γ) = 72.0 mN m-1 a 25 ° C).</li>
	<li>Adicione 1,5 g de estireno, 0,6 g de PFO e 0,9 g de 5 mM de solução aquosa de SDS para um frasco de vidro de 10 mL com uma barra de agitação. Nota: Nas observações de microscopia de fluorescência confocal de varredura, adicione 2,6 mg de cumarina 102 e 0,062 mg de calceína à mistura.</li>
	<li>Agitar a mistura por 60 min em 1.150 rpm sob temperatura ambiente e em seguida, elevar a temperatura de 80 ° C.</li>
	<li>Agitar a mistura por 60 min em 1.150 rpm e 80 ° C.</li>
</ol>2. fabricação de partículas de polímero utilizando emulsões o consistindo de misturas de solução de SDS de estireno/PFO/Aqueous
<ol><li>Adicionar 3,9 mg de potássio peroxodisulfate, 2 mg de pireno, 1,5 g de estireno, 0,6 g de PFO e 0,9 g de 5 mM de solução aquosa de SDS para um frasco de vidro de 10 mL com uma barra de agitação e selá-lo com um septo de borracha.</li>
	<li>Deoxygenate a mistura por bolhas de gás nitrogênio através de uma agulha de seringa por 30 min. Cuidado: Fluir lentamente o gás nitrogênio para não gerar uma grande quantidade de espuma.</li>
	<li>Para preparar a emulsão, agitar a mistura por 60 min a 1.150 rpm e temperatura e, em seguida, elevar a temperatura de 80 ° C.</li>
	<li>Agitar a mistura por 30 min em 1.150 rpm e 80 ° C.</li>
	<li>Transferir a parte nublada (1,8 mL) da solução resultante (3 mL) para o tubo de ensaio e adicione solução de etanol aquoso de 30% para encerrar completamente a reação de polimerização.</li>
	<li>Proceda à sonicação (potência: 130 W, frequência: 4,2 kHz) por 10 min de partículas de polímero resultante de lavar e centrifugar durante 10 minutos a 2300 x g.</li>
	<li>Para obter as partículas de polímero, remova o sobrenadante do tubo de teste.</li>
	<li>Adicione 3 mL de água para os sólidos resultantes no tubo de teste. Proceda à sonicação (potência: 130 W, frequência: 4,2 kHz) por 10 min e centrifugar durante 10 minutos a 2300 g. x remover o sobrenadante do tubo de teste.</li>
	<li>Repita o procedimento de lavagem (passo 2.8) até espuma não é gerada a partir da solução sobrenadante. Evapore a água para obter o sólido de partículas de polímero oco.</li>
</ol>3. preparação de microcápsulas usando as partículas de polímero oco
<ol><li>Adicionar 1 mg de partículas de poliestireno ocas (passo 2.9) e 4 mL de água para um frasco de vidro de 10 mL com uma barra de agitação.</li>
	<li>Proceda à sonicação (potência: 130 W, frequência: 4,2 kHz) por 10 min dispersar as partículas ocas na água.</li>
	<li>Adicionar 0,1 mL de tolueno a água dispersa as partículas e em seguida, agite-o para 1 h a 100 rpm sob temperatura ambiente. Transferi o líquido para um tubo de ensaio. Cuidado: Se aumenta a rotação por minuto, a morfologia das partículas deformarão.</li>
	<li>Centrifugar o líquido durante 10 minutos a 2300 x g para isolar as microcápsulas forma-lo. Remova o tubo de ensaio a solução sobrenadante.</li>
</ol>

<ol>
	<li>Okubo, M., Fujibayashi, T., Terada, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+micron-sized,+monodisperse+polymer+particles+of+disc-like+and+polyhedral+shapes+by+seeded+dispersion+polymerization.">Synthesis of micron-sized, monodisperse polymer particles of disc-like and polyhedral shapes by seeded dispersion polymerization.</a> Colloid Polym Sci. 283 (7), 793-798 (2005).</li><li>Fujibayashi, T., Okubo, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+Thermodynamic+Stability+of+Micron-Sized,+Monodisperse+Composite+Polymer+Particles+of+Disc-like+Shapes+by+Seeded+Dispersion+Polymerization.">Preparation and Thermodynamic Stability of Micron-Sized, Monodisperse Composite Polymer Particles of Disc-like Shapes by Seeded Dispersion Polymerization.</a> Langmuir. 23 (15), 7958-7962 (2007).</li><li>Okubo, M., Fujibayashi, T., Yamada, M., Minami, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micron-sized,+monodisperse,+snowman/confetti-shaped+polymer+particles+by+seeded+dispersion+polymerization.">Micron-sized, monodisperse, snowman/confetti-shaped polymer particles by seeded dispersion polymerization.</a> Colloid Polym Sci. 283 (9), 1041-1045 (2005).</li><li>Xu, S., 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=Generation+of+Monodisperse+Particles+by+Using+Microfluidics:+Control+over+Size,+Shape,+and+Composition.">Generation of Monodisperse Particles by Using Microfluidics: Control over Size, Shape, and Composition.</a> Angew Chem Int Ed. 44 (5), 724-728 (2005).</li><li>Serra, C. A., Chang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic-Assisted+Synthesis+of+Polymer+Particles.">Microfluidic-Assisted Synthesis of Polymer Particles.</a> Chem Eng Tech. 31 (8), 1099-1115 (2008).</li><li>Higuchi, T., Yabu, H., Shimomura, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simple+preparation+of+hemispherical+polystyrene+particles.">Simple preparation of hemispherical polystyrene particles.</a> Colloids Surf A. 284, 250-253 (2006).</li><li>Sun, Z. Q., 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=Nonspherical+Colloidal+Crystals+Fabricated+by+the+Thermal+Pressing+of+Colloidal+Crystal+Chips.">Nonspherical Colloidal Crystals Fabricated by the Thermal Pressing of Colloidal Crystal Chips.</a> Langmuir. 21 (20), 8987-8991 (2005).</li><li>Deng, 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=A+novel+approach+to+the+construction+of+3-D+ordered+macrostructures+with+polyhedral+particles.">A novel approach to the construction of 3-D ordered macrostructures with polyhedral particles.</a> J Mater Chem. 18 (4), 408-415 (2008).</li><li>Hyuk Im, S., Jeong, U., Xia, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymer+hollow+particles+with+controllable+holes+in+their+surfaces.">Polymer hollow particles with controllable holes in their surfaces.</a> Nat Mater. 4 (9), 671-675 (2005).</li><li>Saito, N., Kagari, Y., Okubo, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Colloidal+Stabilizer+on+the+Shape+of+Polystyrene/Poly(methyl+methacrylate)+Composite+Particles+Prepared+in+Aqueous+Medium+by+the+Solvent+Evaporation+Method.">Effect of Colloidal Stabilizer on the Shape of Polystyrene/Poly(methyl methacrylate) Composite Particles Prepared in Aqueous Medium by the Solvent Evaporation Method.</a> Langmuir. 22 (22), 9397-9402 (2006).</li><li>Cai, P. -. j., Tang, Y. -. j., Wang, Y. -. t., Cao, Y. -. j. <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+polystyrene+hollow+spheres+in+W/O/W+multiple+emulsions.">Fabrication of polystyrene hollow spheres in W/O/W multiple emulsions.</a> Mater Chem Phys. 124 (1), 10-12 (2010).</li><li>Liang, S. -. S., Chen, S. -. L., Chen, S. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diverse+macroporous+spheres+synthesized+by+multiple+emulsion+polymerization+for+protein+analyses.">Diverse macroporous spheres synthesized by multiple emulsion polymerization for protein analyses.</a> Chem Commun. 47 (29), 8385-8387 (2011).</li><li>Kondo, Y., Yoshino, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hybrid+fluorocarbon/hydrocarbon+surfactants.">Hybrid fluorocarbon/hydrocarbon surfactants.</a> Curr Opin Colloid Interface Sci. 10 (3-4), 88-93 (2005).</li><li>Takahashi, Y., Kondo, Y., Schmidt, J., Talmon, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-Assembly+of+a+Fluorocarbon-Hydrocarbon+Hybrid+Surfactant:+Dependence+of+Morphology+on+Surfactant+Concentration+and+Time.">Self-Assembly of a Fluorocarbon-Hydrocarbon Hybrid Surfactant: Dependence of Morphology on Surfactant Concentration and Time.</a> J Phys Chem B. 114 (42), 13319-13325 (2010).</li><li>Takahashi, Y., Nasu, Y., Aramaki, K., Kondo, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unusual+viscoelastic+behavior+of+aqueous+solutions+of+fluorocarbon-hydrocarbon+hybrid+surfactant+and+its+morphological+transformations.">Unusual viscoelastic behavior of aqueous solutions of fluorocarbon-hydrocarbon hybrid surfactant and its morphological transformations.</a> J Fluor Chem. 145, 141-147 (2013).</li><li>Yoshino, N., 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=Syntheses+of+Hybrid+Anionic+Surfactants+Containing+Fluorocarbon+and+Hydrocarbon+Chains.">Syntheses of Hybrid Anionic Surfactants Containing Fluorocarbon and Hydrocarbon Chains.</a> Langmuir. 11 (2), 466-469 (1995).</li><li>Zarzar, L. 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=Dynamically+reconfigurable+complex+emulsions+via+tunable+interfacial+tensions.">Dynamically reconfigurable complex emulsions via tunable interfacial tensions.</a> Nature. 518 (7540), 520-524 (2015).</li></ol>

Nós não temos nada para divulgar.

As emulsões contendo gotículas de Janus de estireno e FOP foram obtidas acima de 10% em peso da fração aquosa concentração de SDS de peso e qualquer fração de peso de estireno e FOP. Quando as várias frações-peso das emulsões contendo as gotas de Janus tem sido polimerizadas por 30 min, as partículas de poliestireno ocas podem ser obtidas para a composição de todos. Estes resultados indicam que o protocolo demonstrado aqui é simples. Além disso, o diâmetro do tamanho do furo e volume de buraco de partículas de poliestireno ocas podem ser controlados pelo tempo de polimerização no método descrito aqui.
Sugerimos o seguinte mecanismo para a fabricação das partículas de poliestireno ocas. Gotas de óleo de Janus consistindo de estireno e PFO formaram nas emulsões O/W que contêm misturas de solução aquosa SDS, estireno e FOP a 80 ° C. Gotículas de FOP estão localizadas na superfície das gotículas de estireno. Desde que o KPS, um iniciador de polimerização, é solúvel na fase de água, a polimerização avançará na interface da solução de SDS de estireno/aquosa. Estireno nas emulsões ternários foi polimerizado para poliestireno a 80 ° C, Considerando que a FOP, não tendo nenhum grupos polimerizáveis, permaneceu nas emulsões a essa temperatura. Após a polimerização foi cancelada, um buraco na partícula de poliestireno formou-se pela remoção de FOP. Portanto, as partículas de poliestireno Copa oco-tipo ter um buraco na superfície foram fabricados atany fração de peso de estireno e PFO e os tempos de polimerização.
Adicionar uma pequena quantidade de tolueno para as partículas de poliestireno ocas fabricadas pela polimerização radical para 90 min traz sobre os buracos das partículas de poliestireno oco de vedação. Este fenômeno é consistente com o relatado por Hyuk et al.9. O método capsulatum pode conter um material aquoso em partículas.
Neste artigo, temos demonstrado um método de fabricação de partículas de polímero oca usando as gotas de óleo de Janus consistindo de estireno e FOP, que são mutuamente imiscíveis. O método de preparação de partículas de polímero não-esférica já tem sido estudado por causa de seu potencial uso em várias aplicações. Esta estratégia usando as gotas de óleo de Janus de hidrocarbonetos e óleo de fluorcarbono será aplicada para a fabricação de partículas de polímero não-esférica de vários tipos de sistema de entrega de monômero e drogas.

Enquanto partículas esféricas têm sido amplamente utilizadas em diversas aplicações industriais, é sabido que partículas covinha, hemisférios, discos e elipsoides, foram elaborados pelo semeado polimerizações1,2, 3, foto-polimerização das gotas de monômero não-esférica com geometrias específicas4,5, Microrreator de auto-organização usando precipitação de polímeros6e deformação do polímero esférico partículas por mecânica externa força7,8. Em particular, as partículas de polímero oco com micrômetro-tamanho têm sido inventadas por evaporação de solvente bom de partículas esféricas, inchados pelo solvente9,10 e polimerização usando emulsões múltiplas 11 , 12.
Neste trabalho, focalizamos o uso de rugosidade mútua dos hidrocarbonetos e do fluorocarbon óleos na fabricação de partículas de polímero. Surfactantes híbrido tem uma cadeia de hidrocarbonetos e uma cadeia de fluorcarbono na molécula. Anteriormente, informamos as propriedades únicas de surfactantes híbrido que não são observadas em surfactantes convencionais13,14,15. Também estudamos emulsões usando óleo de hidrocarboneto, óleo de fluorcarbono e solução aquosa de surfactante, que são mutuamente imiscíveis16. No entanto, existem poucos estudos de emulsões17. Estes estudos têm descrito a morfologia das gotículas de óleo consiste em hidrocarbonetos e óleo de fluorcarbono em soluções aquosas de surfactante.
Aqui, nós mostramos um protocolo detalhado de fabricação de partículas de polímero oco pela polimerização radical usando gotas de óleo em emulsões, constituído por hidrocarbonetos, óleo de fluorcarbono e soluções de sódio aquoso dodecylsulfate (SDS). Sugerimos uma nova estratégia, que é diferente dos métodos convencionais, para a preparação de partículas de polímero não-esférica. Esse método pode simplesmente fabricar as partículas de polímero oca em um curto espaço de tempo. Além disso, o protocolo da preparação de microcápsulas através de partículas de polímero oco é mostrado.

<table><tbody><tr><td>&lt;strong&gt;Material&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Sodium dodecylsulfate, 95.0%</td><td>Wako Pure Chemical Industries, Ltd.</td><td>192-08672</td><td></td></tr><tr><td>Styrene, 99.0%</td><td>Tokyo Chemical Industry Co. Ltd.</td><td>S0095</td><td></td></tr><tr><td>Perfluorooctane, 99%</td><td>Fluorochem Ltd.</td><td>8706</td><td></td></tr><tr><td>Coumarin 102, 97.0%</td><td>Tokyo Chemical Industry Co. Ltd.</td><td>C2267</td><td></td></tr><tr><td>Calcein</td><td>Dojindo Molecular Technologies, Inc.</td><td>C001</td><td></td></tr><tr><td>Potassium peroxodisulfate, 98.0%</td><td>Kanto Chemical Co., Inc.</td><td>32375-30</td><td></td></tr><tr><td>Pyrene, 97.0%</td><td>Wako Pure Chemical Industries, Ltd.</td><td>167-05302</td><td></td></tr><tr><td>Ethanol, 99.5%</td><td>Kanto Chemical Co., Inc.</td><td>14033-00</td><td></td></tr><tr><td>Toluene, 99.5%</td><td>Kanto Chemical Co., Inc.</td><td>40180-00</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Scanning Electron Microscope</td><td>Hitachi High-Technologies Corporation</td><td>S-4800</td><td></td></tr><tr><td>Scanning Transmission Electron Microscope</td><td>Hitachi High-Technologies Corporation</td><td>S-4800</td><td></td></tr><tr><td>Ultrasonic cleaner</td><td>Branson Ultrasonics, Emerson Japan, Ltd.</td><td>Model 3510</td><td></td></tr><tr><td>Centrifuge</td><td>AS ONE Corporation</td><td>CN-1050</td><td></td></tr></tbody></table>

preparation of hollow polystyrene particles and microcapsules by radical polymerization of janus droplets consisting of hydrocarbon and fluorocarbon oils

Neste artigo, temos demonstrado um método para produzir partículas ocas e microcápsulas usando gotículas de óleo composto por hidrocarbonetos (estireno) e óleo de fluorcarbono (perfluoro -n-octano, PFO) no surfactante aquosa (dodecylsulfate de sódio, Soluções de SDS). Desde óleos de fluorcarbono são imiscíveis com óleos de hidrocarbonetos, os dois óleos são separados. Emulsões são preparados por mexendo estireno/PFO/aquosa misturas de solução de SDS a 80 ° C. O tipo de emulsões e a morfologia de gotículas nas emulsões são observados por microscópio óptico e microscópio de fluorescência confocal. Pode ser encontrada que gotículas de óleo com morfologias de Janus-tipo consistindo de estireno mutuamente imiscível e FOP são formadas em soluções aquosas de SDS. Partículas de poliestireno são fabricadas pela polimerização radical das misturas ternárias de estireno/PFO/SDS aquoso a 80 ° C. As morfologias do poliestireno são confirmadas pelo microscópio eletrônico de varredura e varredura de observações de microscopia eletrônica de transmissão. Estas observações mostram a preparação de partículas de poliestireno ocas com um único furo na superfície. A nosso conhecimento, este método é uma estratégia de novela usando a rugosidade dos hidrocarbonetos e do fluorocarbon óleos. As partículas ocas também podem ser aplicadas para a preparação de microcápsulas.

Luz e observações de microscopia de fluorescência confocal de varredura foram realizados para determinar a morfologia e a composição de gotículas nas emulsões consistindo de estireno, FOP e solução aquosa de SDS 5 mM (Figura 1). Microscopia eletrônica (SEM) e observações de microscopia eletrônica (tronco) de transmissão de varredura mostraram a formação de partículas ocas e microcápsulas (Figura 2).
O DIC e imagens de microscopia de fluorescência confocal de emulsões consistindo de misturas ternárias de estireno/PFO/SDS aquoso indicam que a fase contínua é a solução aquosa de SDS, porque fluorescência verde correspondente a calceína foi observada em a fase contínua, e portanto, a formação de emulsões do tipo óleo-em-água (Figura 1a e 1b). Estas imagens mostram também que as gotículas de óleo consistem de estireno e FOP, que são mutuamente imiscíveis. O DIC e imagens de microscopia de fluorescência confocal de emulsões contendo cumarina 102 revelam que uma gotícula PFO está localizada na interface entre a água e uma gota de estireno. As misturas ternárias de estireno, FOP e solução aquosa de SDS em emulsões de formulário 5mm contendo Janus óleo gotículas, que consistem de estireno e FOP.
As imagens SEM e haste de partículas de polímero fabricadas pela polimerização radical das emulsões de solução aquosa de SDS estireno/PFO/5mm mostram a preparação de partículas de poliestireno não-esférico ocas com um buraco na superfície (Figura 2a e 2b). A taxa de formação, diâmetro e tamanho das partículas de poliestireno ocas são avaliados pela observação de 200 partículas através de SEM e tronco. O diâmetro em média estimado a partir de observações SEM é 1,3 µm. O tamanho é consistente com o diâmetro das partículas de polímero, estimados a partir de medições de difusão dinâmica da luz. A taxa de formação é de aproximadamente 100%. A média de tamanho de furo e volume do buraco na ocas partículas são 0,8 ± 0,4 µm e 0,9 ± 0,4 µm3, respectivamente. Portanto, as partículas de poliestireno ocas ter um furo de 0,8 µm foram fabricadas pela polimerização radical de gotículas de Janus que contém estireno nas emulsões.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56922/56922fig1.jpg"> Figura 1. Morfologias de gotículas em emulsões consiste em solução aquosa estireno, FOP e 5 mM do SDS. (a) contraste de interferência diferencial (DIC) e (b) imagens de microscopia de fluorescência confocal das emulsões contendo calceína fluorescente aquosa. (c) DIC e (d) fluorescência confocal microscopia imagens das emulsões contendo óleo solúvel cumarina fluorescente 102. <a href="//cloudflare.jove.com/files/ftp_upload/56922/56922fig1large.jpg" target="_blank">Clique aqui para ver uma versão maior desta figura.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56922/56922fig2.jpg"> Figura 2. Morfologias de partículas de poliestireno ocas e microcápsulas fabricadas usando emulsões consiste em solução aquosa estireno, FOP e 5 mM do SDS. (a) SEM e (b) imagens de haste das partículas de poliestireno ocas. (c) SEM e (d) tronco imagens das microcápsulas. <a href="//cloudflare.jove.com/files/ftp_upload/56922/56922fig2large.jpg" target="_blank">Clique aqui para ver uma versão maior desta figura.</a>

Watch this Scientific Journal Video about Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils at J

Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

Preparação de partículas de poliestireno ocas e microcápsulas pela polimerização Radical de gotículas de Janus, constituído por hidrocarbonetos e óleos de fluorcarbono

Um protocolo para a preparação de partículas de polímero oco e microcápsulas pela polimerização radical, usando emulsões consistindo de estireno, perfluoro -n-octano e SDS aquosa (dodecylsulfate de sódio) solução é apresentada.

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) ...

preparation-hollow-polystyrene-particles-microcapsules-radical

Universidad de Cartagena UDEC

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JoVE Journal

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9.9K visualizações.  Tokyo University of Science. Um protocolo para a preparação de partículas de polímero oco e microcápsulas pela polimerização radical, usando emulsões consistindo de estireno, perfluoro -n-octano e SDS aquosa (dodecylsulfate de sódio) solução é apresentada.

Vídeo: Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

Synthesis of Poly(N-isopropylacrylamide) Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability

Janus microparticles are compartmentalized particles with differing molecular structures and/or functionality on each of their two sides. Because of this unique property, Janus microparticles have been recognized as a new class of materials, thereby attracting a great deal of attention from various research fields. The versatility of these microparticles has been exemplified through their uses as building blocks for self-assembly, electrically responsive actuators, emulsifiers for painting and cosmetics, and carriers for drug delivery. This study introduces a detailed protocol that explicitly describes a synthetic method for designing novel Janus microhydrogels composed of a single base material, poly(N-isopropylacrylamide) (PNIPAAm). Janus microdroplets are firstly generated via a hydrodynamic focusing microfluidic device (HFMD) based on the separation of a supersaturated aqueous NIPAAm monomer solution and subsequently polymerized through exposure to UV irradiation. The resulting Janus microhydrogels were found to be entirely composed of the same base material, featured an easily identifiable compartmentalized morphology, and exhibited anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability. We believe that the proposed method introduces a novel hydrogel platform with the potential for advanced synthesis of multi-functional Janus microhydrogels.

Synthesis of PolyN-isopropylacrylamide Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability

We present a protocol to synthesize Janus microhydrogels composed entirely of the same base material, poly(N-isopropylacrylamide) (PNIPAAm), with a clearly compartmentalized structure base on the phase separation of a supersaturated NIPAAm monomer solution. The synthesized Janus microhydrogels show unique properties such as anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability.

Síntese de Poli (<em&gt; N</em&gt; -isopropylacrylamide) Janus Microhydrogels para anisotrópica Thermo-resposta e Organophilic / Carregando Capability hidrofílico

Janus microparticles are compartmentalized particles with differing molecular structures and/or functionality on each of their two sides. Because of this ...

Química

Using Polystyrene-block-poly(acrylic acid)-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are encapsulated in polystyrene-block-poly(acrylic acid) (PSPAA) shells and then used as monomers for their self-assembly. Spherical PSPAA micelles upon acid treatment are known to assemble into cylindrical micelles. Exploiting this tendency, the core-shell nanoparticles are induced to aggregate, coalesce, and then transform into long chains. When more than one type of nanoparticles are used, random and block &#8220;copolymers&#8221; of nanoparticles can be obtained. Detailed procedures are reported for the PSPAA encapsulation of nanoparticles, homo- and co-polymerization of the core-shell nanoparticles, separation and purification of the resulting nanoparticle chains. Transformations of single-line chains into double- and triple-line chains are also presented. The synergy between the polymer shell and the embedded nanoparticles leads to an unusual chain-growth polymerization mode, giving long nanoparticle chains that are distinct from the products of the traditional step-growth aggregation process.

Using Polystyrene-block-polyacrylic acid-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We report protocols for &#8220;polymerizing&#8221; various types of polymer-encapsulated metal nanoparticles into long chains of &#8220;homo-&#8220; and &#8220;co-polymers&#8221;.

Usando Polystyrene-<em&gt; Bloco</em&gt; -poli (Ácido acrílico) -Revestido metal Nanopartículas como monómeros para a sua homo- e co-polimerização

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are ...

High-throughput Synthesis of Carbohydrates and Functionalization of Polyanhydride Nanoparticles

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design efficacious vaccines carriers. Nanoparticle-based platforms can prolong the persistence of vaccine antigens, which could improve vaccine immunogenicity1. Several biodegradable polymers have been studied as vaccine delivery vehicles1; in particular, polyanhydride particles have demonstrated the ability to provide sustained release of stable protein antigens and to activate antigen presenting cells and modulate immune responses2-12.
The molecular design of these vaccine carriers needs to integrate the rational selection of polymer properties as well as the incorporation of appropriate targeting agents. High throughput automated fabrication of targeting ligands and functionalized particles is a powerful tool that will enhance the ability to study a wide range of properties and will lead to the design of reproducible vaccine delivery devices.
The addition of targeting ligands capable of being recognized by specific receptors on immune cells has been shown to modulate and tailor immune responses10,11,13 C-type lectin receptors (CLRs) are pattern recognition receptors (PRRs) that recognize carbohydrates present on the surface of pathogens. The stimulation of immune cells via CLRs allows for enhanced internalization of antigen and subsequent presentation for further T cell activation14,15. Therefore, carbohydrate molecules play an important role in the study of immune responses; however, the use of these biomolecules often suffers from the lack of availability of structurally well-defined and pure carbohydrates. An automation platform based on iterative solution-phase reactions can enable rapid and controlled synthesis of these synthetically challenging molecules using significantly lower building block quantities than traditional solid-phase methods16,17.
Herein we report a protocol for the automated solution-phase synthesis of oligosaccharides such as mannose-based targeting ligands with fluorous solid-phase extraction for intermediate purification. After development of automated methods to make the carbohydrate-based targeting agent, we describe methods for their attachment on the surface of polyanhydride nanoparticles employing an automated robotic set up operated by LabVIEW as previously described10. Surface functionalization with carbohydrates has shown efficacy in targeting CLRs10,11 and increasing the throughput of the fabrication method to unearth the complexities associated with a multi-parametric system will be of great value (Figure 1a).

In this article, a high throughput method is presented for the synthesis of oligosaccharides and their attachment to the surface of polyanhydride nanoparticles for further use in targeting specific receptors on antigen presenting cells.

Alta capacidade de síntese de hidratos de carbono e funcionalização de nanopartículas polianidrido

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design ...

Bioengenharia

High Throughput Single-cell and Multiple-cell Micro-encapsulation

Microfluidic encapsulation methods have been previously utilized to capture cells in picoliter-scale aqueous, monodisperse drops, providing confinement from a bulk fluid environment with applications in high throughput screening, cytometry, and mass spectrometry. We describe a method to not only encapsulate single cells, but to repeatedly capture a set number of cells (here we demonstrate one- and two-cell encapsulation) to study both isolation and the interactions between cells in groups of controlled sizes. By combining drop generation techniques with cell and particle ordering, we demonstrate controlled encapsulation of cell-sized particles for efficient, continuous encapsulation. Using an aqueous particle suspension and immiscible fluorocarbon oil, we generate aqueous drops in oil with a flow focusing nozzle. The aqueous flow rate is sufficiently high to create ordering of particles which reach the nozzle at integer multiple frequencies of the drop generation frequency, encapsulating a controlled number of cells in each drop. For representative results, 9.9 &mu;m polystyrene particles are used as cell surrogates. This study shows a single-particle encapsulation efficiency Pk=1 of 83.7% and a double-particle encapsulation efficiency Pk=2 of 79.5% as compared to their respective Poisson efficiencies of 39.3% and 33.3%, respectively. The effect of consistent cell and particle concentration is demonstrated to be of major importance for efficient encapsulation, and dripping to jetting transitions are also addressed. 
Introduction 
Continuous media aqueous cell suspensions share a common fluid environment which allows cells to interact in parallel and also homogenizes the effects of specific cells in measurements from the media. High-throughput encapsulation of cells into picoliter-scale drops confines the samples to protect drops from cross-contamination, enable a measure of cellular diversity within samples, prevent dilution of reagents and expressed biomarkers, and amplify signals from bioreactor products. Drops also provide the ability to re-merge drops into larger aqueous samples or with other drops for intercellular signaling studies.1,2 The reduction in dilution implies stronger detection signals for higher accuracy measurements as well as the ability to reduce potentially costly sample and reagent volumes.3 Encapsulation of cells in drops has been utilized to improve detection of protein expression,4 antibodies,5,6 enzymes,7 and metabolic activity8 for high throughput screening, and could be used to improve high throughput cytometry.9 Additional studies present applications in bio-electrospraying of cell containing drops for mass spectrometry10 and targeted surface cell coatings.11 Some applications, however, have been limited by the lack of ability to control the number of cells encapsulated in drops. Here we present a method of ordered encapsulation12 which increases the demonstrated encapsulation efficiencies for one and two cells and may be extrapolated for encapsulation of a larger number of cells.
To achieve monodisperse drop generation, microfluidic "flow focusing" enables the creation of controllable-size drops of one fluid (an aqueous cell mixture) within another (a continuous oil phase) by using a nozzle at which the streams converge.13 For a given nozzle geometry, the drop generation frequency f and drop size can be altered by adjusting oil and aqueous flow rates Qoil and Qaq. As the flow rates increase, the flows may transition from drop generation to unstable jetting of aqueous fluid from the nozzle.14 
When the aqueous solution contains suspended particles, particles become encapsulated and isolated from one another at the nozzle. For drop generation using a randomly distributed aqueous cell suspension, the average fraction of drops Dk containing k cells is dictated by Poisson statistics, where Dk = &lambda;k exp(-&lambda;)/(k!) and &lambda; is the average number of cells per drop. The fraction of cells which end up in the "correctly" encapsulated drops is calculated using Pk = (k x Dk)/&Sigma;(k' x Dk'). The subtle difference between the two metrics is that Dk relates to the utilization of aqueous fluid and the amount of drop sorting that must be completed following encapsulation, and Pk relates to the utilization of the cell sample. As an example, one could use a dilute cell suspension (low &lambda;) to encapsulate drops where most drops containing cells would contain just one cell. While the efficiency metric Pk would be high, the majority of drops would be empty (low Dk), thus requiring a sorting mechanism to remove empty drops, also reducing throughput.15
Combining drop generation with inertial ordering provides the ability to encapsulate drops with more predictable numbers of cells per drop and higher throughputs than random encapsulation. Inertial focusing was first discovered by Segre and Silberberg16 and refers to the tendency of finite-sized particles to migrate to lateral equilibrium positions in channel flow. Inertial ordering refers to the tendency of the particles and cells to passively organize into equally spaced, staggered, constant velocity trains. Both focusing and ordering require sufficiently high flow rates (high Reynolds number) and particle sizes (high Particle Reynolds number).17,18 Here, the Reynolds number Re =uDh/&nu; and particle Reynolds number Rep =Re(a/Dh)2, where u is a characteristic flow velocity, Dh [=2wh/(w+h)] is the hydraulic diameter, &nu; is the kinematic viscosity, a is the particle diameter, w is the channel width, and h is the channel height. Empirically, the length required to achieve fully ordered trains decreases as Re and Rep increase. Note that the high Re and Rep requirements (for this study on the order of 5 and 0.5, respectively) may conflict with the need to keep aqueous flow rates low to avoid jetting at the drop generation nozzle. Additionally, high flow rates lead to higher shear stresses on cells, which are not addressed in this protocol. The previous ordered encapsulation study demonstrated that over 90% of singly encapsulated HL60 cells under similar flow conditions to those in this study maintained cell membrane integrity.12 However, the effect of the magnitude and time scales of shear stresses will need to be carefully considered when extrapolating to different cell types and flow parameters. The overlapping of the cell ordering, drop generation, and cell viability aqueous flow rate constraints provides an ideal operational regime for controlled encapsulation of single and multiple cells.
Because very few studies address inter-particle train spacing,19,20 determining the spacing is most easily done empirically and will depend on channel geometry, flow rate, particle size, and particle concentration. Nonetheless, the equal lateral spacing between trains implies that cells arrive at predictable, consistent time intervals. When drop generation occurs at the same rate at which ordered cells arrive at the nozzle, the cells become encapsulated within the drop in a controlled manner. This technique has been utilized to encapsulate single cells with throughputs on the order of 15 kHz,12 a significant improvement over previous studies reporting encapsulation rates on the order of 60-160 Hz.4,15 In the controlled encapsulation work, over 80% of drops contained one and only one cell, a significant efficiency improvement over Poisson (random) statistics, which predicts less than 40% efficiency on average.12
In previous controlled encapsulation work,12 the average number of particles per drop &lambda; was tuned to provide single-cell encapsulation. We hypothesize that through tuning of flow rates, we can efficiently encapsulate any number of cells per drop when &lambda; is equal or close to the number of desired cells per drop. While single-cell encapsulation is valuable in determining individual cell responses from stimuli, multiple-cell encapsulation provides information relating to the interaction of controlled numbers and types of cells. Here we present a protocol, representative results using polystyrene microspheres, and discussion for controlled encapsulation of multiple cells using a passive inertial ordering channel and drop generation nozzle.

Combining monodisperse drop generation with inertial ordering of cells and particles, we describe a method to encapsulate a desired number of cells or particles in a single drop at kHz rates. We demonstrate efficiencies twice exceeding those of unordered encapsulation for single- and double-particle drops.

Alta taxa de transferência de célula única e múltipla de células Micro-encapsulamento

Microfluidic encapsulation methods have been previously utilized to capture cells in picoliter-scale aqueous, monodisperse drops, providing confinement ...

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

Síntese Facile de micelas Worm-like por luz visível Mediated Dispersão Polimerização Usando Photoredox Catalisador

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by &#960;-&#960; Stacking Interactions

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE). Characterization of the copolymer revealed a narrow molecular distribution (PDI &#60; 1.03) and confirmed the degree of polymerization of mPEG122-b-(PheGE)15. The critical micelle concentration of the copolymer was evaluated using an established fluorescence method with the aggregation behavior evaluated by dynamic light scattering and transmission electronic microscopy. The potential of the copolymer for use in drug delivery applications was evaluated in a preliminary manner including in vitro biocompatibility, loading and release of the hydrophobic anti-cancer drug doxorubicin (DOX). A stable micelle formulation of DOX was prepared with drug loading levels up to 14% (wt%), drug loading efficiencies &#62; 60% (w/w) and sustained release of drug over 4 days under physiologically relevant conditions (acidic and neutral pH, presence of albumin). The high drug loading level and sustained release is attributed to stabilizing &#960;-&#960; interactions between DOX and the core-forming block of the micelles.

The key steps of living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE) are described. The resulting block copolymer micelles (BCMs) were loaded with doxorubicin 14% (wt%) and sustained release of drug over 4 days under physiologically relevant conditions was obtained.

Aniônico polimerização de um copolímero anfifílicas para Preparação de copolímero em bloco As micelas estabilizada por interacções de empilhamento π-¸

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl ...

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, interface precipitation, and mini-emulsion. In all methods, well-defined, micrometer-sized spheres are obtained from a self-assembling process in solution. The vapor diffusion method can result in spheres with the highest sphericity and surface smoothness, yet the types of the polymers able to form these spheres are limited. On the other hand, in the mini-emulsion method, microspheres can be made from various types of polymers, even from highly crystalline polymers with coplanar, &#960;-conjugated backbones. The photoluminescent (PL) properties from single isolated microspheres are unusual: the PL is confined inside the spheres, propagates at the circumference of the spheres via the total internal reflection at the polymer/air interface, and self-interferes to show sharp and periodic resonant PL lines. These resonating modes are so-called "whispering gallery modes" (WGMs). This work demonstrates how to measure WGM PL from single isolated spheres using the micro-photoluminescence (&#181;-PL) technique. In this technique, a focused laser beam irradiates a single microsphere, and the luminescence is detected by a spectrometer. A micromanipulation technique is then used to connect the microspheres one by one and to demonstrate the intersphere PL propagation and color conversion from coupled microspheres upon excitation at the perimeter of one sphere and detection of PL from the other microsphere. These techniques, &#181;-PL and micromanipulation, are useful for experiments on micro-optic application using polymer materials.

Protocols for the synthesis of microspheres from polymers, the manipulation of microspheres, and micro-photoluminescence measurements are presented.

Fabricação de Microsferas de Polímeros para Resonadores Ópticos e Aplicações Laser

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, ...

Engenharia

Microfluidic Preparation of Liquid Crystalline Elastomer Actuators

This paper focuses on the microfluidic process (and its parameters) to prepare actuating particles from liquid crystalline elastomers. The preparation usually consists in the formation of droplets containing low molar mass liquid crystals at elevated temperatures. Subsequently, these particle precursors are oriented in the flow field of the capillary and solidified by a crosslinking polymerization, which produces the final actuating particles. The optimization of the process is necessary to obtain the actuating particles and the proper variation of the process parameters (temperature and flow rate) and allows variations of size and shape (from oblate to strongly prolate morphologies) as well as the magnitude of actuation. In addition, it is possible to vary the type of actuation from elongation to contraction depending on the director profile induced to the droplets during the flow in the capillary, which again depends on the microfluidic process and its parameters. Furthermore, particles of more complex shapes, like core-shell structures or Janus particles, can be prepared by adjusting the setup. By the variation of the chemical structure and the mode of crosslinking (solidification) of the liquid crystalline elastomer, it is also possible to prepare actuating particles triggered by heat or UV-vis irradiation.

This article describes the microfluidic process and parameters to prepare actuating particles from liquid crystalline elastomers. This process allows the preparation of actuating particles and the variation of their size and shape (from oblate to strongly prolate, core-shell, and Janus morphologies) as well as the magnitude of actuation.

Microfluidic preparação dos atuadores do líquido cristalino de elastômero

This paper focuses on the microfluidic process (and its parameters) to prepare actuating particles from liquid crystalline elastomers. The preparation ...

Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock copolymers are produced by one of three techniques: thin film rehydration, solvent switching or polymerization-induced self-assembly, and produce only flexible, polydisperse cylinders. Crystallization-driven self-assembly (CDSA) is a method which can produce cylinders with these properties, by stabilizing structures of a lower curvature due to the formation of a crystalline core. However, the living polymerization techniques by which most core-forming blocks are formed are not trivial processes and the CDSA process may yield unsatisfactory results if carried out incorrectly. Here, the synthesis of cylindrical nanoparticles from simple reagents is shown. The drying and purification of reagents prior to a ring-opening polymerization of &#949;-caprolactone catalyzed by diphenyl phosphate is described. This polymer is then chain extended by methyl methacrylate (MMA) followed by N,N-dimethyl acrylamide (DMA) using reversible addition&#8722;fragmentation chain-transfer (RAFT) polymerization, affording a triblock copolymer that can undergo CDSA in ethanol. The living CDSA process is outlined, the results of which yield cylindrical nanoparticles up to 500 nm in length and a length dispersity as low as 1.05. It is anticipated that these protocols will allow others to produce cylindrical nanostructures and elevate the field of CDSA in the future.

Crystallization-driven self-assembly (CDSA) displays the unique ability to fabricate cylindrical nanostructures of narrow length distributions. The organocatalyzed ring-opening polymerization of &#949;-caprolactone and subsequent chain extensions of methyl methacrylate and N,N-dimethyl acrylamide are demonstrated. A living CDSA protocol that produces monodisperse cylinders up to 500 nm in length is outlined.

Síntese de nanopartículas cilíndricas Monodispersa via auto-montagem orientada por cristalização de copolímeros de blocos biodegradáveis

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock ...

A Droplet-Based Microfluidic Approach and Microsphere-PCR Amplification for Single-Stranded DNA Amplicons

Droplet-based microfluidics enable the reliable production of homogeneous microspheres in the microfluidic channel, providing controlled size and morphology of the obtained microsphere. A microsphere copolymerized with an acrydite-DNA probe was successfully fabricated. Different methods such as asymmetric PCR, exonuclease digestion, and isolation on streptavidin-coated magnetic beads can be used to synthesize single-stranded DNA (ssDNA). However, these methods cannot efficiently use large amounts of highly purified ssDNA. Here, we describe a microsphere-PCR protocol detailing how ssDNA can be efficiently amplified and separated from dsDNA simply by pipetting from a PCR reaction tube. The amplification of ssDNA can be applied as potential reagents for the DNA microarray and DNA-SELEX (Systematic evolution of ligands by exponential enrichment) processes.

This work provides a method for the fabrication of droplet-based microfluidic platforms and the application of polyacrylamide microspheres for microsphere-PCR amplification. The microsphere-PCR method makes it possible to obtain single-stranded DNA amplicons without separating double-stranded DNA.

Preparação de partículas de poliestireno ocas e microcápsulas pela polimerização Radical de gotículas de Janus, constituído por hidrocarbonetos e óleos de fluorcarbono

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Usando Polystyrene-