Microfluidic Technology-based Circulation Tumor Cell Enrichment And Purification Studies

Research on circulating tumor cells has been a hot topic in cancer-related research.The current research has confirmed that it can be used as a prognosis marker for lung cancer,breast cancer,colorectal cancer,and other cancers,Moreover,it has positive research significance for early screening of cancer,adjuvant diagnosis,treatment evaluation,recurrence detection and personalized diagnosis and treatment.However,due to the scarcity of circulating tumor cells and difficulties in obtaining them,researchers are exploring how to isolate high purity circulating tumor cells from patients.The emergence of microfluidics has provided a low-cost and efficient solution for people.By using different microfluidic chips,we can complete the separation and purification of circulating tumor cells.While,in clinical trials,researchers need to pre-process sampling samples before the experiment,,thus reducing the working efficiency.Therefore,three kinds of microfluidic chips with different functions have be developed and the related experimental system has been built to realize the separation and purification of circulating tumor cells.The main contents of this paper are as follows:(1)Designed and fabricated a circulating tumor cell enriched chip based on cell size and deformation capability,and based on programmable pressure controller set up a microfluidic driving platform.By applying an oscillatory flow to the chip,the H1299 lung cancer tumor cells were collected in specific flow channels.Experiments have found that the best results are obtained when the oscillating pressure is 90 mbar and the oscillation frequency is 0.33 Hz.This enrichment mode can effectively prevent chip blockage and other problems that may appear in clinical trials,and has high potential for application.(2)Designed and fabricated a CTC parcel chip based on inertial focus structure.Carrying out contrast experiments with three different structures(DC channel focusing,helical channel focusing,and inertial channel focusing).By observing the experimental results,it can be found that the two-way tapered nozzle structure can provide stable pressure for the droplet generation.The inertial flow channel can effectively solve the problem of single-cell drop rate caused by cell clustering.(3)Designed and fabricated a droplet sorting chip by using DEP effect,and a low-cost detection and control platform was built based on the data acquisition card and Labview program.Through experiments,it was verified that the detection of the liquid droplet with fluorescence and the separation of the target droplet by the EDP effect were working effectively.of this system.It has been initially demonstrated that this sorting method can effectively sort droplets with single tumor cells and achieve highly purified tumor cells sample.This paper is using tumor cells as the sample.Preliminarily verified that microfluidic chip and its system can achieve systematic work in enriching and purifying tumor cells,and provide theoretical and experimental support for the further application of microfluidic technology in clinical tumor analysis.