多功能芯片对合成样本中肝癌细胞HepG2的测试研究

设计并制作了一种集多孔流分离(Multi-orifice flow fractionation,MOFF)技术与磁捕获技术于一体的用于特异性分离和捕获合成样本中肝癌细胞Hep G2的多功能微流控细胞芯片。此芯片由玻璃基片和PDMS微通道盖片组成,PDMS盖片上含有3条进样通道、MOFF分离区和六边形腔体的细胞富集检测区。其中,MOFF分离区总长20 mm,由80组长度为0.18 mm、深度为50μm、收缩区域宽度为0.06 mm、扩张区域宽度为0.20 mm的半菱形收缩/扩张重复单元组成,每组收缩/扩张重复单元间的夹角为103.0°。实验以肝癌细胞Hep G2-血细胞混悬液为样本;根据磁珠表面修饰c-Met抗体能与肝癌细胞Hep G2特异性结合的原理,通过表面羧基化的磁珠、EDC(1 mg/m L)、NHS(1 mg/m L)和c-Met抗体制备了浓度为50μg/m L的免疫磁珠(AntiMNCs)悬浮液。在样本流速为50μL/min条件下,利用外加磁场实现了血细胞合成样本中微量肝癌细胞Hep G2的有效捕获;采用微波加热法以柠檬酸、硫脲为原料制备了用于荧光标记Hep G2的碳量子点,在芯片上实现了血液中肝癌细胞Hep G2的原位荧光可视化观测。对芯片检测区捕获到的Hep G2进行了显微计数分析,对500μL血细胞(107cell/m L)中含10个Hep G2细胞的合成样本,捕获效率达到88.5%±6.7%(n=20)。结果表明,所设计的多模式多功能的微流控芯片具有良好的肿瘤细胞分离和检测功能。

Liquid Flow in a Porous Channel with Electrokinetic Effects

In this paper, a fully developed laminar flow in a porous channel between two paralleled flat plates in the presence of a double layer electric field is analyzed. The linear Poisson-Boltzmann equation is suggested to model the double layer electric field near the solid-liquid interface. The equation of motion is extended by including the electrical body force generating from the double layer field and then solved analytically. Different from previous models, our proposed one is continuous in the whole flow field and matches commonly-accepted models in the field of fluid mechanics.Besides, the effects of various physical parameters such as the zeta potential, the electrokinetic separation distance, and the ratio of the streaming current to conduction current on the velocity, the pressure, the apparent viscosity of the fluid,as well as the streaming potential are discussed. Physical explanations on the changing trends of those physical quantities with various parameters are given.