YG é apoiado por uma bolsa de estudos do BID. IN é um companheiro Alon e um colega da faculdade da J Edmond ‭. ‬ Safra Centro de Bioinformática da Universidade de Tel Aviv ‭. ‬ Esta pesquisa foi apoiada pela ISF concessão 1499-1410.

1. Criando um Mestre Scotch-5 <ol><li> Desenhar ou imprimir desejado disposição de microcanais, à escala, no papel. No nosso caso, o desenho consiste em dois canais em forma de Y, cada uma com 3 mm de largura (Figura 2). </li><li> Cobrir uma lâmina de vidro com camadas de fita adesiva. O número de camadas irá determinar a altura do canal (cerca de 60 mM por camada). Foram usados ​​3 camadas de fita adesiva. </li><li> Coloque o projeto de layout em uma superfície plana. Alinhe o slide sobre o padrão de design. Cuidadosamente cortar a fita na lâmina de vidro com um bisturi de acordo com o layout. </li><li> Retire a fita adesiva de todas as regiões da lâmina de vidro, exceto aqueles no layout do microcanal. </li><li> Colocar as lâminas em um forno de aquecimento a 65 ° C durante 2-3 min. Limpar cuidadosamente com etanol. </li></ol> 2. A fabricação de um dispositivo micro PDMS <ol><li> Misturar a base e os componentes de cura de PDMS, tal como recomendado pelo fabricante. Nós usamos uma mistura 10:1proporção da base para o agente de cura. Verter cerca de 30 ml da mistura de PDMS em uma placa de Petri a uma altura de ~ 0,5 cm. Desgasificar o PDMS em vácuo, se necessário. Corrediça submergir o vidro no PDMS com a fita Scotch padronizada voltada para cima. Colocar o padrão após o PDMS, evita a formação de bolhas de ar entre a corrediça e inferior do prato. Curar durante 48 horas a 65 ° C, garantindo que o prato está horizontal utilizando um nível de bolha. </li><li> Num prato de 90 milímetros novo Petri despeje 3 ml de mistura de PDMS, o que resulta em uma camada de cerca de 0,5 mm de profundidade. (Se um revestidor de rotação estiver disponível, ele pode ser usado para esta fase). </li><li> Degas e curar, como em 2.1. </li><li> Gentilmente cortar o dispositivo micro para o tamanho desejado com um bisturi. Esta camada será chamado de &quot;camada de fluxo&quot;. </li><li> Corte um pedaço do mesmo tamanho de fina camada de PDMS da placa de Petri segundo. Isto irá ser chamado de &quot;camada poços&quot;. </li><li> Usar um perfurador de biópsia de tamanho apropriado (Usamos 1,2 mm ID) para os furos para as entradas e as saídas da camada de fluxo. </li&gt; <li> Coloque a camada poços numa lâmina de vidro de espessura sobre a topografia e perfurador de poços, utilizando 2 mm ID perfurador de biópsia, em alinhamento com os microcanais no layout. </li><li> Limpar ambas as camadas de PDMS, bem como uma lamela de vidro de 24 mm x 60 mm com etanol. Ar seco e manter limpo. </li><li> Plasma tratar tanto a lamela de vidro e da camada de PDMS poços usando etcher plasma padrão (para ligação não-reversível) ou de um tratador de mão corona 6 para ligação reversível. Coloque cuidadosamente a camada de poços em cima da lamela para provocar a adesão (Figura 3). Esfregue suavemente para fora todas as bolhas de ar (se necessário). </li></ol> 3. Experimento imagens de células <ol><li> Certifique-se de que você tem a mídia desejada pronto em seringas apropriadas ligadas a tubos flexíveis de plástico com diâmetro interno de 0,02 &quot;(Tygon) na bomba de seringa. </li><li> Crescer S. cerevisiae para a fase desejada de YPD líquido. Vortex completamente e local μ 300l de cada estirpe num tubo de microcentrífuga. </li><li> Coloque suavemente 1 ul de Concanavalina A (Sigma) 2 mg / ml em cada poço. Lavar Concanavalina excesso Um de cada poço duas vezes com cuidado pipetando água. </li><li> Enquanto a Concanavalina A secagem é, estirpes lavar duas vezes com 300 ul de meio sem glicose SC. Lavagem glucose residual das paredes das células contribui para a aderência adequada Concanavalina A. </li><li> Células Vortex cuidadosamente. Pipetar 0,75 jil ou menos de cada suspensão de células no seu próprio bem (Figura 3). Gentilmente lavar células residuais com meio rico. Os dois passos seguintes devem ser realizadas rapidamente, a fim de evitar que as células se esgote. </li><li> Plasma tratar o chip e os poços, cuidadosamente, com o tratador de mão corona, tomando cuidado para não bater os poços diretamente. Com cuidado, coloque o chip nos poços, prestando muita atenção ao alinhamento entre os dois (este passo pode ser feito sob um estereoscópio). Pressione suavemente a aderir as duas camadas de PDMS. Encher lentamente o dispositivo completamente com cerca de 50 ul de meio rico, certificando-se de nenhuma bolha de ar é deixado no interior do canal. </li><li> Conectar o dispositivo, inserindo os tubos para as entradas adequadas e iniciar o fluxo de mídia. Ter cuidado para que nenhuma bolha de ar são introduzidas no dispositivo, tal como estas podem ser difíceis de remover, isto pode ser conseguido através de desconectar uma entrada ou saída e batendo suavemente no dispositivo em que as bolhas são, tendo cuidado para não romper a lamela de vidro. </li><li> Colocar sob microscópio e encontrar os pontos de imagem apropriados em cada poço. </li><li> Manter as células sob fluxo de meio rico durante 1 hora ou mais para permitir a recuperação, se necessário. </li><li> Iniciar a experiência: usamos fluxo constante de cada uma das duas bombas de seringa para impedir o refluxo dos meios de comunicação, alterando as taxas de fluxo relativas, como desejado. Configuração da bomba A a 0,8 ml / hr e B da bomba para 0,2 ml / hr resulta em meio A que flui ao longo de 80% da largura do canal (Fig. 4). Isto pode ser dinamicamente cpendurado alterando os dois caudais. As novas condições estabilizar dentro de segundos ao longo de todo o comprimento do canal 2. </li></ol>

<ol>
	<li>Dertinger, S. K., Jiang, X., Li, Z., Murthy, V. N., Whitesides, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gradients+of+substrate-bound+laminin+orient+axonal+specification+of+neurons.">Gradients of substrate-bound laminin orient axonal specification of neurons.</a> Proceedings of the National Academy of Sciences of the United States of America. 99, 12542-12547 (2002).</li><li>Hersen, P., McClean, M. N., Mahadevan, L., Ramanathan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Signal+processing+by+the+HOG+MAP+kinase+pathway.">Signal processing by the HOG MAP kinase pathway.</a> Proc. Natl. Acad. Sci. U.S.A. 105, 7165-7170 (2008).</li><li>Paliwal, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MAPK-mediated+bimodal+gene+expression+and+adaptive+gradient+sensing+in+yeast.">MAPK-mediated bimodal gene expression and adaptive gradient sensing in yeast.</a> Nature. 446, 46-51 (2007).</li><li>Bennett, M. R., Hasty, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+devices+for+measuring+gene+network+dynamics+in+single+cells.">Microfluidic devices for measuring gene network dynamics in single cells.</a> Nat. Rev. Genet. 10, 628-638 (2009).</li><li>Shrirao, A. B., Perez-Castillejos, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simple+Fabrication+of+Microfluidic+Devices+by+Replicating+Scotch-tape+Masters.">Simple Fabrication of Microfluidic Devices by Replicating Scotch-tape Masters.</a> Chips &#38; Tips. , (2010).</li><li>Haubert, K., Drier, T., Beebe, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PDMS+bonding+by+means+of+a+portable,+low-cost+corona+system.">PDMS bonding by means of a portable, low-cost corona system.</a> Lab Chip. 6, 1548-1549 (2006).</li><li>Gerber, D., Maerkl, S. J., Quake, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vitro+microfluidic+approach+to+generating+protein-interaction+networks.">An in vitro microfluidic approach to generating protein-interaction networks.</a> Nat. Methods. 6, 71-74 (2009).</li></ol>

Não há conflitos de interesse declarados.

Neste artigo, apresentamos um método de bancada simples para criar um dispositivo micro que permite seguintes cepas de leveduras simultaneamente vários em condições dinâmicas. Na sequência de várias estirpes de um canal fornece uma ferramenta fiável para comparar dinâmica de respostas de células individuais em várias estirpes. Uma vantagem da nossa abordagem é a capacidade para fabricar o dispositivo com técnicas simples sem a necessidade de uma sala limpa. Na verdade, nós também realizaram o protocolo pu...

As células são constantemente reagindo a um ambiente de alterar dinamicamente, alterando o seu metabolismo, o perfil de transcrição e funções celulares. Para estudar estes fenômenos, os métodos capazes de quantificar essas mudanças são necessárias. Um tipo de leitura para tais respostas é a mudança de localização de factores de transcrição relacionados com stress, em resposta ao stress nutricional. Microfluídico dispositivos 1 ter sido usado para manipular dinamicamente as condições ambientais para as células 2-4. Eles apresentam várias vantagens para imagens de células vivas: o ambiente do que as células podem ser controladas com precisão e alterados dinamicamente, as células podem estar vivas, com imagens em todas as vezes, incluindo durante a manipulação das condições externas, e os volumes de reagentes mínimos são obrigatórios. Uma concepção muito simples para um dispositivo de microfluidos, que permite a alternância entre duas condições, é um dispositivo em forma de Y 2. Nós usam rotineiramente em forma de Y dispositivos microfluídicos que permitemaplicação de mudanças dinâmicas para as células do canal. Usamos este dispositivo para acompanhar as mudanças de localização de fluorescente etiquetado estresse fatores de transcrição relacionados em células de levedura. Nós seguimos essas mudanças sob novas condições nutricionais. Por exemplo, pode-se fornecer um impulso (ou uma série de impulsos) de glucose contendo meio dentro de um período de não-glicose média, com uma resolução muito fina temporal. Muitas vezes, em tais experiências, um está interessado em comparar as respostas de linhagens celulares diferentes (por exemplo, os mutantes diferentes, ou diferentes isolados selvagens). O canal em forma de Y é limitada a uma estirpe de cada um dos canais - se mais do que uma estirpe é utilizado, não há nenhuma maneira simples para distinguir entre as estirpes. Para superar isto, os canais podem ser usados ​​diferentes. Se quiser aplicar as mesmas condições dinâmicas para várias cepas, gostaríamos de combinar o conceito Y canais com múltiplos canais. Existem dois desafios na implementação desta solução: Pode ser difícil de aplicar tele mesmas condições, ao mesmo tempo para todos os canais, e não é uma limitação geométrica do número de canais de Y que podem ser montados em um único dispositivo. Fomos, pois, procurando uma maneira para visualizar várias linhagens em um canal em condições dinâmicas. Descrevemos aqui um dispositivo de duas camadas destinado a microfluídico estirpes de imagens múltiplas em um canal, nas mesmas condições dinâmicas. A camada inferior é constituída por PDMS fina com uma fileira de furos. Esta camada está ligada à lamela de vidro de furos em que irá colocar as diferentes estirpes, aderindo-as com concanavalina A para o vidro. A segunda camada é um dispositivo em forma de Y microfluídico criados usando o método da fita adesiva 5. Depois de colocar as estirpes nas cavidades da segunda camada é rapidamente alinhados e ligados com a primeira, a criação de um canal com vários poços que contêm as diferentes estirpes. Este dispositivo permite a última sequência de várias estirpes de um canal, onde todosestirpes são submetidos às mesmas condições, no momento exacto mesmo. Este conjunto e processo de produção pode ser feito sobre a bancada, usando meios simples, sem litografia suave.

<table border="1"><tbody><tr><td> Reagente / Equipamento </td><td> Companhia </td><td> Número de catálogo </td></tr><tr><td> PDMS-184 SYLGARD </td><td> Dow Corning EUA </td><td></td></tr><tr><td> Exsicador de vácuo </td><td> Nalgene </td><td> 5310-0250 </td></tr><tr><td> Biópsia perfuradores </td><td> Ted Pella Inc. </td><td> Harris Uni-Core 15076 (2 mm), 15,074 (1,2 mm) </td></tr><tr><td> Bombas de seringa </td><td> Chemyx </td><td> Fusão 200 </td></tr><tr><td> Corona tratador </td><td> Electro-técnica produtos </td><td> BD-20 </td></tr><tr><td> Tubagem Tygon </td><td> Tygon </td><td> S-54-HL </td></tr><tr><td> Concanavalina-A </td><td> Sigma </td><td> C7275 </td></tr><tr><td> Fita adesiva </td><td> 3M Scotch </td><td> Fita Transparente 1/2 &quot; </td></tr></tbody></table>

a microfluidic device for studying multiple distinct strains

O estudo de respostas de células para as alterações ambientais coloca muitos desafios experimentais: as células têm de ser trabalhada sob condições variáveis, muitas vezes, de uma forma comparativa. Placas com vários poços são usados ​​rotineiramente para comparar várias espécies diferentes ou linhas de células, mas permitem um controle limitado sobre a dinâmica do ambiente. Dispositivos microfluidicos, por outro lado, permite o controle dinâmico requintado nas condições do ambiente, mas é um desafio para imagem e distinguir mais do que algumas estirpes neles. Aqui nós descrevemos um método para facilmente e rapidamente fabricar um dispositivo micro capaz de aplicar condições de alterar dinamicamente a várias cepas de leveduras distintas em um canal. O dispositivo está concebido e fabricado por meios simples, sem necessidade de litografia suave. É composto por um canal de fluxo em forma de Y ligado a uma segunda camada portadora micropoços. As estirpes são colocados em micropoços separados, e visualizados sob as mesmas condições dinâmicas. Nós demonstrate a utilização do dispositivo para a medição das respostas de localização de proteínas de pulsos de alterações de nutrientes em diferentes estirpes de levedura.

Para demonstrar a separação entre as diferentes estirpes que imaged duas estirpes de levedura distinguíveis em poços alternados. Imagiologia dos poços cheio mostra nenhuma fuga de células entre os poços (Figura 5a, b). Ambas as estirpes possuem o factor de transcrição MSN2 marcado com YFP. Para testar o efeito simultâneo de alterar dinamicamente condições, as taxas de fluxo ligado em dois canais de entrada, criando um passo de não-glicose média, o que resultou na localização de MSN2-YFP ...

Watch this Scientific Journal Video about A Microfluidic Device for Studying Multiple Distinct Strains at JoVE.com

A Microfluidic Device for Studying Multiple Distinct Strains

Apresenta-se um método simples para a produção de dispositivos microfluídicos capazes de aplicar semelhantes condições dinâmicas de múltiplas linhagens distintas, sem a necessidade de uma sala de limpeza ou de litografia suave.

Um dispositivo micro para o Estudo múltiplas linhagens distintas

The study of cell responses to environmental changes poses many experimental challenges: cells need to be imaged under changing conditions, often in a ...

a-microfluidic-device-for-studying-multiple-distinct-strains

Research

JoVE Journal

Bioengineering

8.7K visualizações.  Tel Aviv University. Apresenta-se um método simples para a produção de dispositivos microfluídicos capazes de aplicar semelhantes condições dinâmicas de múltiplas linhagens distintas, sem a necessidade de uma sala de limpeza ou de litografia suave.

Vídeo: A Microfluidic Device for Studying Multiple Distinct Strains

Microfluidic Device for Recreating a Tumor Microenvironment in Vitro

We have developed a microfluidic device that mimics the delivery and systemic clearance of drugs to heterogeneous three-dimensional tumor tissues in vitro. Nutrients delivered by vasculature fail to reach all parts of tumors, giving rise to heterogeneous microenvironments consisting of viable, quiescent and necrotic cell types. Many cancer drugs fail to effectively penetrate and treat all types of cells because of this heterogeneity. Monolayers of cancer cells do not mimic this heterogeneity, making it difficult to test cancer drugs with a suitable in vitro model. Our microfluidic devices were fabricated out of PDMS using soft lithography. Multicellular tumor spheroids, formed by the hanging drop method, were inserted and constrained into rectangular chambers on the device and maintained with continuous medium perfusion on one side. The rectangular shape of chambers on the device created linear gradients within tissue. Fluorescent stains were used to quantify the variability in apoptosis within tissue. Tumors on the device were treated with the fluorescent chemotherapeutic drug doxorubicin, time-lapse microscopy was used to monitor its diffusion into tissue, and the effective diffusion coefficient was estimated. The hanging drop method allowed quick formation of uniform spheroids from several cancer cell lines. The device enabled growth of spheroids for up to 3 days. Cells in proximity of flowing medium were minimally apoptotic and those far from the channel were more apoptotic, thereby accurately mimicking regions in tumors adjacent to blood vessels. The estimated value of the doxorubicin diffusion coefficient agreed with a previously reported value in human breast cancer. Because the penetration and retention of drugs in solid tumors affects their efficacy, we believe that this device is an important tool in understanding the behavior of drugs, and developing new cancer therapeutics.

Microfluidic Device for Recreating a Tumor Microenvironment in Vitro

We present the procedure for fabrication and operation of a microfluidic device that recreates heterogeneous tumor microenvironments in vitro. The variability in apoptosis within tumor tissue was quantified using fluorescent stains and the effective diffusion coefficient of the chemotherapeutic drug doxorubicin into tumor tissue was evaluated.

Dispositivo microfluídicos para Recriando um microambiente do tumor<em&gt; In Vitro</em

We have developed a microfluidic device that mimics the delivery and systemic clearance of drugs to heterogeneous three-dimensional tumor tissues in ...

Bioengenharia

Microfluidic Mixers for Studying Protein Folding

The process by which a protein folds into its native conformation is highly relevant to biology and human health yet still poorly understood. One reason for this is that folding takes place over a wide range of timescales, from nanoseconds to seconds or longer, depending on the protein1. Conventional stopped-flow mixers have allowed measurement of folding kinetics starting at about 1 ms. We have recently developed a microfluidic mixer that dilutes denaturant ~100-fold in ~8 &mu;s2. Unlike a stopped-flow mixer, this mixer operates in the laminar flow regime in which turbulence does not occur. The absence of turbulence allows precise numeric simulation of all flows within the mixer with excellent agreement to experiment3-4.
Laminar flow is achieved for Reynolds numbers Re &le;100. For aqueous solutions, this requires micron scale geometries. We use a hard substrate, such as silicon or fused silica, to make channels 5-10 &mu;m wide and 10 &mu;m deep (See Figure 1). The smallest dimensions, at the entrance to the mixing region, are on the order of 1 &mu;m in size. The chip is sealed with a thin glass or fused silica coverslip for optical access. Typical total linear flow rates are ~1 m/s, yielding Re~10, but the protein consumption is only ~0.5 nL/s or 1.8 &mu;L/hr. Protein concentration depends on the detection method: For tryptophan fluorescence the typical concentration is 100 &mu;M (for 1 Trp/protein) and for FRET the typical concentration is ~100 nM.
The folding process is initiated by rapid dilution of denaturant from 6 M to 0.06 M guanidine hydrochloride. The protein in high denaturant flows down a central channel and is met on either side at the mixing region by buffer without denaturant moving ~100 times faster (see Figure 2). This geometry causes rapid constriction of the protein flow into a narrow jet ~100 nm wide. Diffusion of the light denaturant molecules is very rapid, while diffusion of the heavy protein molecules is much slower, diffusing less than 1 &mu;m in 1 ms. The difference in diffusion constant of the denaturant and the protein results in rapid dilution of the denaturant from the protein stream, reducing the effective concentration of the denaturant around the protein. The protein jet flows at a constant rate down the observation channel and fluorescence of the protein during folding can be observed using a scanning confocal microscope5.

In this work we explain the fabrication and use of a microfluidic mixer capable of mixing two solutions in ~8 &mu;s. We also demonstrate the use of these mixers with spectroscopic detection using UV fluorescence and fluorescence resonance energy transfer (FRET).

Misturadores microfluídicos para Estudar o dobramento de proteínas

The process by which a protein folds into its native conformation is highly relevant to biology and human health yet still poorly understood. One reason ...

Protocol for Biofilm Streamer Formation in a Microfluidic Device with Micro-pillars

Several bacterial species possess the ability to attach to surfaces and colonize them in the form of thin films called biofilms. Biofilms that grow in porous media are relevant to several industrial and environmental processes such as wastewater treatment and CO2 sequestration. We used Pseudomonas fluorescens, a Gram-negative aerobic bacterium, to investigate biofilm formation in a microfluidic device that mimics porous media. The microfluidic device consists of an array of micro-posts, which were fabricated using soft-lithography. Subsequently, biofilm formation in these devices with flow was investigated and we demonstrate the formation of filamentous biofilms known as streamers in our device. The detailed protocols for fabrication and assembly of microfluidic device are provided here along with the bacterial culture protocols. Detailed procedures for experimentation with the microfluidic device are also presented along with representative results.

Protocols for the study of biofilm formation in a microfluidic device that mimics porous media are discussed. The microfluidic device consists of an array of micro-pillars and biofilm formation by Pseudomonas fluorescens in this device is investigated.

Protocolo para a formação de biofilme Streamer em um dispositivo micro com micro-pilares

Several bacterial species possess the ability to attach to surfaces and colonize them in the form of thin films called biofilms. Biofilms that grow in ...

Analyzing Mixing Inhomogeneity in a Microfluidic Device by Microscale Schlieren Technique

In this paper, we introduce the use of microscale schlieren technique to measure mixing inhomogeneity in a microfluidic device. The microscale schlieren system is constructed from a Hoffman modulation contrast microscope, which provides easy access to the rear focal plane of the objective lens, by removing the slit plate and replacing the modulator with a knife-edge. The working principle of microscale schlieren technique relies on detecting light deflection caused by variation of refractive index1-3. The deflected light either escapes or is obstructed by the knife-edge to produce a bright or a dark band, respectively. If the refractive index of the mixture varies linearly with its composition, the local change in light intensity in the image plane is proportional to the concentration gradient normal to the optical axis. The micro-schlieren image gives a two-dimensional projection of the disturbed light produced by three-dimensional inhomogeneity.
To accomplish quantitative analysis, we describe a calibration procedure that mixes two fluids in a T-microchannel. We carry out a numerical simulation to obtain the concentration gradient in the T-microchannel that correlates closely with the corresponding micro-schlieren image. By comparison, a relationship between the grayscale readouts of the micro-schlieren image and the concentration gradients presented in a microfluidic device is established. Using this relationship, we are able to analyze the mixing inhomogeneity from associate micro-schlieren image and demonstrate the capability of microscale schlieren technique with measurements in a microfluidic oscillator4. For optically transparent fluids, microscale schlieren technique is an attractive diagnostic tool to provide instantaneous full-field information that retains the three-dimensional features of the mixing process.

Herein, we describe a procedure that employs microscale schlieren technique to measure mixing inhomogeneity in a microfluidic device. Through calibration, distribution of concentration gradient can be derived from the micro-schlieren image.

Analisando falta de homogeneidade de mistura em um dispositivo micro, pela técnica Microscale Schlieren

In this paper, we introduce the use of microscale schlieren technique to measure mixing inhomogeneity in a microfluidic device. The microscale schlieren ...

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

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

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

Totalmente dispositivo automático centrífugo microfluídicos para a detecção de proteínas Ultrasensitive de Sangue Total

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

Co-culture of Living Microbiome with Microengineered Human Intestinal Villi in a Gut-on-a-Chip Microfluidic Device

Here, we describe a protocol to perform long-term co-culture of multi-species human gut microbiome with microengineered intestinal villi in a human gut-on-a-chip microphysiological device. We recapitulate the intestinal lumen-capillary tissue interface in a microfluidic device, where physiological mechanical deformations and fluid shear flow are constantly applied to mimic peristalsis. In the lumen microchannel, human intestinal epithelial Caco-2 cells are cultured to form a &#39;germ-free&#39; villus epithelium and regenerate small intestinal villi. Pre-cultured microbial cells are inoculated into the lumen side to establish a host-microbe ecosystem. After microbial cells adhere to the apical surface of the villi, fluid flow and mechanical deformations are resumed to produce a steady-state microenvironment in which fresh culture medium is constantly supplied and unbound bacteria (as well as bacterial wastes) are continuously removed. After extended co-culture from days to weeks, multiple microcolonies are found to be randomly located between the villi, and both microbial and epithelial cells remain viable and functional for at least one week in culture. Our co-culture protocol can be adapted to provide a versatile platform for other host-microbiome ecosystems that can be found in various human organs, which may facilitate in vitro study of the role of human microbiome in orchestrating health and disease.

We describe an in vitro protocol to co-culture gut microbiome and intestinal villi for an extended period using a human gut-on-a-chip microphysiological system.

Co-cultura de Vida Microbiome com Intestinal Microengineered Humano Villi num Gut-on-a-Chip Microfluidic Dispositivo

Here, we describe a protocol to perform long-term co-culture of multi-species human gut microbiome with microengineered intestinal villi in a human ...

Dry Film Photoresist-based Electrochemical Microfluidic Biosensor Platform: Device Fabrication, On-chip Assay Preparation, and System Operation

In recent years, biomarker diagnostics became an indispensable tool for the diagnosis of human disease, especially for the point-of-care diagnostics. An easy-to-use and low-cost sensor platform is highly desired to measure various types of analytes (e.g., biomarkers, hormones, and drugs) quantitatively and specifically. For this reason, dry film photoresist technology - enabling cheap, facile, and high-throughput fabrication - was used to manufacture the microfluidic biosensor presented here. Depending on the bioassay used afterwards, the versatile platform is capable of detecting various types of biomolecules. For the fabrication of the device, platinum electrodes are structured on a flexible polyimide (PI) foil in the only clean-room process step. The PI foil serves as a substrate for the electrodes, which are insulated with an epoxy-based photoresist. The microfluidic channel is subsequently generated by the development and lamination of dry film photoresist (DFR) foils onto the PI wafer. By using a hydrophobic stopping barrier in the channel, the channel is separated into two specific areas: an immobilization section for the enzyme-linked assay and an electrochemical measurement cell for the amperometric signal readout.
The on-chip bioassay immobilization is performed by the adsorption of the biomolecules to the channel surface. The glucose oxidase enzyme is used as a transducer for electrochemical signal generation. In the presence of the substrate, glucose, hydrogen peroxide is produced, which is detected at the platinum working electrode. The stop-flow technique is applied to obtain signal amplification along with rapid detection. Different biomolecules can quantitatively be measured by means of the introduced microfluidic system, giving an indication of different types of diseases, or, in regard to therapeutic drug monitoring, facilitating a personalized therapy.

A microfluidic biosensor platform was designed and fabricated using low-cost dry film photoresist technology for the rapid and sensitive quantification of various analytes. This single-use system allows for the electrochemical readout of on-chip-immobilized enzyme-linked assays by means of the stop-flow technique.

Película seca baseada em fotorresiste eletroquímica Microfluidic Biosensor plataforma: Fabricação de dispositivo, ensaio em-microplaqueta preparação e operação de sistema

In recent years, biomarker diagnostics became an indispensable tool for the diagnosis of human disease, especially for the point-of-care diagnostics. An ...

Perfusable Vascular Network with a Tissue Model in a Microfluidic Device

A spheroid (a multicellular aggregate) is regarded as a good model of living tissues in the human body. Despite the significant advancement in the spheroid cultures, a perfusable vascular network in the spheroids remains a critical challenge for long-term culture required to maintain and develop their functions, such as protein expressions and morphogenesis. The protocol presents a novel method to integrate a perfusable vascular network within the spheroid in a microfluidic device. To induce a perfusable vascular network in the spheroid, angiogenic sprouts connected to microchannels were guided to the spheroid by utilizing angiogenic factors from human lung fibroblasts cultured in the spheroid. The angiogenic sprouts reached the spheroid, merged with the endothelial cells co-cultured in the spheroid, and formed a continuous vascular network. The vascular network could perfuse the interior of the spheroid without any leakage. The constructed vascular network may be further used as a route for supply of nutrients and removal of waste products, mimicking blood circulation in vivo. The method provides a new platform in spheroid culture toward better recapitulation of living tissues.

The protocol describes how to engineer a perfusable vascular network in a spheroid. The spheroid's surrounding microenvironment is devised to induce angiogenesis and connect the spheroid to the microchannels in a microfluidic device. The method allows the perfusion of the spheroid, which is a long-awaited technique in three-dimensional cultures.

Perfusable rede Vascular com um modelo de tecido em um dispositivo Microfluidic

A spheroid (a multicellular aggregate) is regarded as a good model of living tissues in the human body. Despite the significant advancement in the ...

Generation of Dynamical Environmental Conditions using a High-Throughput Microfluidic Device

Mimicking in vivo environmental conditions is crucial for in vitro studies on complex life machinery. However, current techniques targeting live cells and organs are either highly expensive, like robotics, or lack nanoliter volume and millisecond time accuracy in liquid manipulation. We herein present the design and fabrication of a microfluidic system, which consists of 1,500 culture units, an array of enhanced peristaltic pumps and an on-site mixing modulus. To demonstrate the capacities of the microfluidic device, neural stem cell (NSC) spheres are maintained in the proposed system. We observed that when the NSC sphere is exposed to CXCL in day 1 and EGF in day 2, the round-shaped conformation is well maintained. Variation in the input order of 6 drugs causes morphological changes to the NSC sphere and the expression level representative marker for NSC stemness (i.e., Hes5 and Dcx). These results indicate that dynamic and complex environmental conditions have great effects on NSC differentiation and self-renewal, and the proposed microfluidic device is a suitable platform for high throughput studies on the complex life machinery.

We present a microfluidic system for high throughput studies on complex life machinery, which consists of 1500 culture units, an array of enhanced peristaltic pumps and an on-site mixing modulus. The microfluidic chip allows for the analysis of the highly complex and dynamic micro-environmental conditions in vivo.

Geração de Condições Ambientais Dinâmicas usando um dispositivo microfluido de alto rendimento

Mimicking in vivo environmental conditions is crucial for in vitro studies on complex life machinery. However, current techniques targeting live cells and ...

Configuração de um dispositivo microfluídico para produção combinatória de plugues

Bilayer Microfluidic Device for Combinatorial Plug Production

Droplet microfluidics is a versatile tool that allows the execution of a large number of reactions in chemically distinct nanoliter compartments. Such systems have been used to encapsulate a variety of biochemical reactions - from incubation of single cells to implementation of PCR reactions, from genomics to chemical synthesis. Coupling the microfluidic channels with regulatory valves allows control over their opening and closing, thereby enabling the rapid production of large-scale combinatorial libraries consisting of a population of droplets with unique compositions. In this paper, protocols for the fabrication and operation of a pressure-driven, PDMS-based bilayer microfluidic device that can be utilized to generate combinatorial libraries of water-in-oil emulsions called plugs are presented. By incorporating software programs and microfluidic hardware, the flow of desired fluids in the device can be controlled and manipulated to generate combinatorial plug libraries and to control the composition and quantity of constituent plug populations. These protocols will expedite the process of generating combinatorial screens, particularly to study drug response in cells from cancer patient biopsies.

Autor em destaque: Integrando abordagens computacionais e experimentais em oncologia de precisão

The fabrication of a polydimethylsiloxane (PDMS)-based bilayer device for the production of combinatorial libraries in water-in-oil emulsions (plugs) is presented here. The necessary hardware and software required to automate plug production are detailed in the protocol, and the production of a quantitative library of fluorescent plugs is also demonstrated.

Dispositivo microfluídico bicamada para produção de plugue combinatório

Droplet microfluidics is a versatile tool that allows the execution of a large number of reactions in chemically distinct nanoliter compartments. Such ...