Detection of HepG2 Cells in Artificial Samples by Multifunctional Microfluidic Chip

Abstract

Abstract A multifunctional microfluidic chip integrated with multi-orifice flow fractionation (MOFF) and magnetic capture technique was developed to specifically separate and capture HepG2 cells in artificial samples. The chip contained a glass substrate and a polydimethylsiloxane (PDMS) micro-channel cover plate. The PDMS cover plate consisted of three 10-mm-long injection channels, a MOFF separation zone and a hexagonal cavity cell enrichment detection zone. The MOFF separation zone, with a total length of 20 mm, was consisted of 80 semi-rhombic shrinkage and 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 and expansion units was 103.0°. In this work, HepG2-blood cell suspension was used as the sample. Based on the principle that the magnetic beads surface modified c-Met antibody could specifically bind to HepG2 cells, an immune-magnetic beads (anti-MNCs) suspension at a concentration of 50 μg mL−1 was prepared by surface carboxylated beads, EDC (1 mg mL−1), NHS (1 mg mL−1) and c-Met antibody. At the optimized flow rate of 50 μL min−1, HepG2 in suspension samples was 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 made it possible that the captured HepG2 could be visualized in-situ. The captured cells in the chip detection area were counted by microscope. It was shown that the capture rate of HepG2 cells was 88.5% ± 6.7% (500 μL volume contained 106 blood cells and 10 HepG2 cells). The results demonstrated the developed multifunctional microfluidic chip may serve as a promising tool for separation and capture of tumour cells.