Capture And Release Of Circulating Tumor Cells Based On Physical Filtration

Circulating tumor cells are shedding tumor cells from the primary tumor tissue,they exist in the peripheral blood circulation system,and can form a new tumor tissue through metastasis,invasion and proliferation.Metastasis of tumor cells cause malignant tumor easy to recur,hard to cure.At present,it is difficult to detect early tumor symptoms based on the mainstream treatment of pathology and imaging,but CTCs can be detected in the circulatory system in the early stage of the tumor,so the detection of CTCs provides a new way for early diagnosis and treatment of tumors.Early detection of CTCs is of great importance in exploring tumor metastasis mechanism,evaluating therapeutic effect and individualized treatment.CTCs are extremely rare in the peripheral blood,which poses a major challenge to CTCs detection.CTCs have a certain difference in physical and biological characteristics from normal cells.Based on these differences,the current methods for detecting CTCs can be divided into two categories based on physical characteristics and biological characteristics.The filtration,one of the methods based on physical properties,has the advantages of high throughput,easy operation,easy to maintain cell morphology and activity,and is of great value in clinical application.On the basis of many studies on the pore structure of the filter,it is found that grating-shaped holes have obvious advantages in high throughput,capture efficiency and reducing flow resistance,so the grating-shaped hole is selected as the pore structure of the thin film filter in this paper,and grating-shaped silicon nitride thin film filter is fabricated with micro fabrication technology,microfluidic chip is fabricated by soft lithography,with which,cancer cells are captured effectively with high viability,and the influence of grating-shaped hole size and velocity on capture efficiency are also discussed.In order to further study and increase reusable rate of the thin film filter,captured cells are attempted to be released from the thin film filter,however,because of the adhesion,the release efficiency is quite low.Through analysis of the mechanism and influencing factors of the adhesion between the cells and the membrane surface,the heparin is used in the filtration and release experiments,which significantly improves the release efficiency of the cells,and can ensure the viability of the cells.Finally,the above microfluidic chip and experimental method are applied to the analysis of blood samples of clinical patients,the captured cells can be released efficiently from the film filter.This indicates that the microfluidic chip and experimental method in this paper are applicable for clinical analysis.