Novel Capture And Release Technologies Of Circulating Tumor Cells

Metastasis and recurrence of cancer are the main causes of death in patients with malignant tumors.Circulating tumor cell?CTCs?are cells that shed from the surface of primary tumor tissue and enter into the peripheral blood of patients.The detection of CTCs from peripheral blood samples has the advantages of simple,high sensitivity and specificity,and real-time monitoring of disease development,which is very important for early detection and treatment of cancer.However,the rarity,heterogeneity,atypical morphology and uncertainty of cell morphology and classification of tumor cells have caused great obstacles to the sorting and research of CTCs.With the further research of oncology,the continuous development of molecular biology,the continuous innovation of biomedical nanomaterials and the gradual improvement of microfluidic technology,a series of new technologies for sorting CTCs have emerged,which consist of two types:biomedical nanomaterials and microfluidic chips.Biomedical nanomaterial substrates show strong affinity for targeted rare cells and are closely related to cell adhesion,migration and proliferation.which directly affects the interaction between the cell and the substrate.Pre-improving the capture efficiency of CTCs can be achieved by increasing the roughness of the nano-substrate,that is,increasing the contact area between substrates and cells,improving the loading capacity to antibodies,enhancing the interaction between the substrate and cell surface components.For the microfluidic chip,it integrates several experimental operating platforms into a small chip,and can automatically complete the preparation,reaction,separation and detection of samples on the same chip.In addition,its unique structure is very close to the cell size,requiring a small number of samples,high sensitivity,convenient for cell manipulation and research,and has a wide range of applications in the cell field.This paper combines the respective advantages of intelligent biomaterials and microfluidic chips,using nanomaterials with good biocompatibility to achieve efficient capture and non-destructive release of circulating tumor cells.and further through laser heating or surface acoustic wave devices to obtain a single target cell.The main research contents are as follows:1.Efficient capture and high activity release of circulating tumor cells by using TiO₂ nanorod arrays coated with soluble MnO₂ nanoparticles.The effects of nanomaterial substrates with different roughness and incubation time on the capture efficiency of cell lines are studied,and the pseudopod extension of cells with different structures is observed by scanning electron microscope.Low concentration oxalic acid is used to dissolve MnO₂ nanoparticles,and the cell activity and proliferation ability after release are studied.We use this platform to carry out the capture experiment of tumor cells in artificial blood and patient samples,combing with three-color fluorescence to identify the target cells.2.The detection and fixed-point release of circulating tumor cells based on the three-dimensional gelatin substrate.We use micro-nano processing technology to prepare gelatin substrate and research the effect of antibodies and microstructure on capture efficiency,employing temperature and matrix metalloproteinases to release cells.We also study the relationship between the temperature and release efficiency.Under the optimized experimental conditions,the capture and release of CTCs from simulated blood samples and patients'peripheral blood are carried out,and the morphology of cells isolated from different types of patients are observed.The laser is used to promote the local substrate melting to realize the fixed-point release of circulating tumor cell.3.We combine ZnO nanofiber substrate with surface acoustic waves to achieve efficient detection of CTCs and obtain a single target cell.The ZnO nanofiber network structure is prepared by electrospinning technology,which is more matched with the extracellular matrix scaffold structure of cells in size,increasing the contact area between the substrate and the cell,and improving the cell capture efficiency.The morphology of ZnO nanofibers prepared under different electrospinning time is observed,and the effects of sparse density,antibody and incubation time of ZnO nanofibers on the capture efficiency are studied.Low concentration of phosphoric acid is used to dissolve ZnO nanofibers to release the captured cells,and the effect of phosphoric acid concentration on the release efficiency and activity of cells is studied.Put the released CTCs into solution of sodium alginate and based on droplet generation with focused acoustic beams for single circulating tumor cells encapsulation.We optimize the optimum concentration of sodium alginate solution,studing the size distribution of droplet and the cell encapsulating ratio under different pulse width.We further use three-color fluorescence identification of encapsulated cells in droplet and extract target cells based on microcapillary,subsequently conduct single cell analysis.