Discovery of single cells physical properties through cell manipulation

Abstract

In recent years, the study of cancer cells and cancer has been one of the most popular and urgent problems in scientific research. These precise information of living cells such as adhesion force and Young's modulus in the physical properties of cells are believed to be helpful in more clearly classifying different types of cancer cells and distinguishing them from benign cells, and the mechanical factors of cells can predict the location of metastasis, which can help to understand the metastatic characteristics of cancer cells in a more in-depth way, which is of great importance in the diagnosis, analysis and treatment of cancer cells. The focus of this thesis is on the manipulation and information acquisition of cancer cells and healthy cells at the nanoscale to achieve innovation in data processing methods, databases and the availability of new drug development methods. In this thesis, Fe3O4 magnetic nanoparticles were synthesised using co-deposition and tested for biocompatibility and toxicity, confirming that it can be used in biological experiments. Subsequently, its concentration was investigated in relation to the tendency and trajectory of the cells in a magnetic field. A correlation between the movement of the cells and the concentration of the magnetic nanoparticles was observed and found by using atomic force microscopy in concert with a magnetic field. Based on cell proliferation characteristics, 3D models of different numbers of cells were constructed to simulate stress and strain based on the application of a constant external force, and the results were compared with three classical contact models (Hertz-Sneddon model, JKR model and DMT model), and it was found that the Hertz-Sneddon model had the best fit in the region near the nucleus. II This thesis proposes a new data processing method based on a large amount of data. On this basis, three types of cells from human liver, one type of cancer cells from human lung and two types of cells from human skin were studied. It was found that the shape of the cells is likely to be the basis for determining the origin of the cells, and the physical properties of the cells are also likely to be the basis for determining whether the cells are cancerous or not. It should be noted, however, that if the physical properties of the cells are used as a basis for determining whether the cells are cancerous or not, they must be considered in conjunction with the origin of the cells and with reference to the time of culture and the cell cycle. Astragalus polysaccharide was extracted from dried astragalus and used to study the effect of different concentrations of astragalus polysaccharide solutions on human immortalised hepatocytes HL-7702 and human HCC SMMC-7721 at different culture times. Their morphology and characteristic physical information were obtained by MTT experiments and using AFM, and the efficacy of APS was found to correlate with culture time and concentration. At low concentration and short culture time, it promoted the proliferation of benign cells and inhibited the growth of malignant cells. When both the concentration and incubation time of APS were increased, Young's modulus and cell adhesion were altered. Meanwhile, APS could induce early apoptosis in human hepatocytes and hepatocellular carcinoma cells.