Department of Mechanical Engineering , Indian Institute of Technology Kharagpur , Kharagpur , West Bengal - 721302 , India.
Department of Biotechnology , Indian Institute of Technology Kharagpur , Kharagpur , West Bengal - 721302 , India.
Anal Chem. 2020 Jan 7;92(1):838-844. doi: 10.1021/acs.analchem.9b03364. Epub 2019 Dec 10.
We demonstrate a method of concentrating and patterning of biological cells on a chip, exploiting the confluence of electric and thermal fields, without necessitating the use of any external heating or illuminating sources. The technique simply employs two parallel plate electrodes and an insulating layer over the bottom electrode, with a drilled insulating layer for inducing localized variations in the thermal field. A strong induced electric field, in the process, penetrates through the narrow hole and generates highly nonuniform heating, which in turn, results in gradients in electrical properties and induces mobile charges to impose directional fluid flow. The toroidal vortices, induced by secondary electrokinetic forces originating out of temperature-dependent electrical property variations, transport the suspended cells toward a hot-spot site of the chip, for rapid concentrating and patterning into different shaped clusters based on predesigned conditions, without exceeding safe temperature limits that do not result in damage of thermally labile biological samples. We characterize the efficacy of the cell trapping process for two different biological entities, namely, bacteria and yeast cells. These results have importance toward developing biomedical microdevices for drug discovery, antibiotic resistance assessment, and medical diagnostics.
我们展示了一种在芯片上浓缩和模式化生物细胞的方法，利用电场和热场的融合，而不需要使用任何外部加热或照明源。该技术仅使用两个平行板电极和底部电极上的绝缘层，以及一个用于诱导热场局部变化的钻孔绝缘层。在这个过程中，强感应电场穿透狭窄的孔并产生高度不均匀的加热，这反过来又导致电性能的梯度，并诱导可移动电荷施加定向流体流动。由温度相关电性能变化引起的二次电动力量引起的环形涡旋将悬浮细胞输送到芯片的热点位置，以便根据预定条件快速浓缩和模式化为不同形状的簇，而不会超过不会导致热敏生物样品损坏的安全温度限制。我们对两种不同的生物实体（即细菌和酵母细胞）的细胞捕获过程的功效进行了表征。这些结果对于开发用于药物发现、抗生素耐药性评估和医学诊断的生物医学微器件具有重要意义。
