多功能芯片对合成样本中肝癌细胞HepG2的测试研究

摘要

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HepG2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HepG2-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HepG2特异性结合的原理,通过表面羧基化的磁珠、EDC(1 mg/mL)、NHS(1 mg/mL)和c-Met抗体制备了浓度为50μg/mL的免疫磁珠(Anti-MNCs)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HepG2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HepG2的碳量子点,在芯片上实现了血液中肝癌细胞HepG2的原位荧光可视化观测.对芯片检测区捕获到的HepG2进行了显微计数分析,对500μL血细胞(107 cell/mL)中含10个HepG2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.%A multi-functional microfluidic chip with multi-orifice flow fractionation ( MOFF) and magnetic capture technique was developed to specifically separate and capture the HepG2 cells in artificial samples. The chip contained a glass substrate and a polydimethylsiloxane ( PDMS) microchannel cover plate. The PDMS cover plate consisted of 3 injection channels of 10-mm-long, a MOFF separation zone and a hexagonal cavity cell enrichment-detection zone. Among which, the MOFF separation zone had a total length of 20 mm and was consisted of 80 semi-rhombic shrinkage / expansion units with a length of 0. 18 mm, a depth of 50 μm, a shrinkage area width of 0. 06 mm, and an expansion area of 0. 20 mm. The angle between each group of shrinkage / expansion units was 103. 0°. In this experiment, HepG2-blood cell suspension was used as the sample. Based on the principle that the magnetic bead surface-modified c-Met antibody could specifically bind to HepG2 cells, an immunomagnetic bead ( Anti-MNCs) suspension at a concentration of 50 μg / mL was prepared by surface carboxylated beads, EDC (1 mg / mL), NHS (1 mg / mL) and c-Met antibody. Under the optimized flow rate (50 μL/ min), a few HepG2 in suspension samples were efficiently captured at the detection zone of chip via a magnetic field; the carbon quantum dots were prepared by microwave heating with citric acid and thiourea to label HepG2 cells which achieved in-situ fluorescence visualization of captured HepG2. Cells captured in the chip detection area were counted by microscope. The capture rate of HepG2 cells was 88. 5% ±6. 7% (106 blood cells and 10 HepG2 cells per 500 μL). The results demonstrated that the developed multifunctional microfluidic chip may serve as a promising tool for separation and capture of tumour cells.