Yadav Shital, Tawade Pratik, Bachal Ketaki, Rakshe Makrand A, Pundlik Yash, Gandhi Prasanna S, Majumder Abhijit
Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India.
Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai, India.
Biomicrofluidics. 2022 Dec 5;16(6):064103. doi: 10.1063/5.0126616. eCollection 2022 Dec.
Microfluidic concentration gradient generators are useful in drug testing, drug screening, and other cellular applications to avoid manual errors, save time, and labor. However, expensive fabrication techniques make such devices prohibitively costly. Here, in the present work, we developed a microfluidic concentration gradient generator (μCGG) using a recently proposed non-conventional photolithography-less method. In this method, ceramic suspension fluid was shaped into a square mesh by controlling Saffman Taylor instability in a multiport lifted Hele-Shaw cell (MLHSC). Using the shaped ceramic structure as the template, μCGG was prepared by soft lithography. The concentration gradient was characterized and effect of the flow rates was studied using COMSOL simulations. The simulation result was further validated by creating a fluorescein dye (fluorescein isothiocanate) gradient in the fabricated μCGG. To demonstrate the use of this device for drug testing, we created various concentrations of an anticancer drug-curcumin-using the device and determined its inhibitory concentration on cervical cancer cell-line HeLa. We found that the IC of curcumin for HeLa matched well with the conventional multi-well drug testing method. This method of μCGG fabrication has multiple advantages over conventional photolithography such as: (i) the channel layout and inlet-outlet arrangements can be changed by simply wiping the ceramic fluid before it solidifies, (ii) it is cost effective, (iii) large area patterning is easily achievable, and (iv) the method is scalable. This technique can be utilized to achieve a broad range of concentration gradient to be used for various biological and non-biological applications.
微流控浓度梯度发生器在药物测试、药物筛选及其他细胞应用中十分有用，可避免人工误差、节省时间和劳动力。然而，昂贵的制造技术使得此类设备成本过高。在此，在本工作中，我们使用最近提出的非传统无光刻方法开发了一种微流控浓度梯度发生器（μCGG）。在该方法中，通过控制多端口提升式赫勒-肖细胞（MLHSC）中的萨夫曼-泰勒不稳定性，将陶瓷悬浮液成型为方形网格。以成型的陶瓷结构为模板，通过软光刻制备μCGG。利用COMSOL模拟对浓度梯度进行了表征，并研究了流速的影响。通过在制造的μCGG中创建荧光素染料（异硫氰酸荧光素）梯度，进一步验证了模拟结果。为了证明该设备在药物测试中的应用，我们使用该设备创建了各种浓度的抗癌药物姜黄素，并确定了其对宫颈癌细胞系HeLa的抑制浓度。我们发现姜黄素对HeLa的半数抑制浓度（IC）与传统的多孔药物测试方法匹配良好。这种μCGG制造方法相对于传统光刻具有多个优点，例如：（i）在陶瓷流体固化前简单擦拭即可改变通道布局和进出口布置；（ii）具有成本效益；（iii）易于实现大面积图案化；（iv）该方法具有可扩展性。该技术可用于实现广泛的浓度梯度，以用于各种生物和非生物应用。
