Research On Applications Of Atomic Force Microscopy In Detecting Nanomechanical Properties Of Clinical Primary Cells

Prostate cancer is one of the most common cancers.It is easy to confuse benign prostatic hyperplasia with prostate cancer and delay the optimal period of treatment by relying on the content of prostate specific antigen(PSA)as a clinical marker in early diagnosis.If the mechanical properties of cells are used as an auxiliary detection method,the accuracy of cancer diagnosis will be improved in early diagnosis.Atomic force microscope(AFM)has become an important tool for the biological research due to its subnanonewton sensitivity,nanometer spatial resolution,and adaptability to physiological environments,which has been widely used in the fields of tumorigenesis,aggravation and migration,and development of organisms.In this paper,50 prostate clinical cell lines from 44 prostate patients and 2 general commercial cell lines were used as research samples.Surface morphology and nanomechanical properties(elastic modulus,adhesion and viscosity)of benign proliferative cell lines and various Gleason score prostate cancer cell lines were obtained through AFM.By combining three biological methods,immunofluorescence staining,western blotting,and Transwell chamber experiments,an effective biomarker is provided for the early diagnosis of clinical prostate cancer cells by analyzing the molecular mechanism of changes in the mechanical properties of cells.First,how to extract three mechanical properties(elastic modulus,surface adhesion and viscoelasticity)of cells from AFM indentation experiments was analyzed theoretically.Independent of traditional approach-hold-retract AFM indentation experiments to obtain viscoelasticity,the relevant models were respectively used to extract elastic modulus,adhesion force and viscoelasticity from the force-displacement curve generated by the approach-retract AFM indentation experiment.Moreover,heatmaps of the mechanical properties were drawn according to the scanning range of cells.Then,on the premise of ensuring good cell survival,the surface morphology and nanomechanical properties of benign prostatic hyperplasia cells and cancer cells were obtained by AFM after determining AFM experimental parameters and subsequent data analysis methods.Based on the experimental data,the correlation between the three mechanical properties(elastic modulus,adhesion and viscosity)and the contribution rate of each mechanical properties to the cells were analyzed.It was the elasticity of cells that was used to explore the individual differences between the same cells.Finally,by combining two biological experiments of immunofluorescence staining and western blotting,the relationships between the nanomechanical properties and intracellular proteins of benign cells and cancer cells,cancer cells of different malignant degrees,and sensitive and non-sensitive cancer cells were determined at the molecular level.Based on this,the relationship between the invasion,metastasis ability and nanomechanical properties of cells was also analyzed by Transwell chamber experiments.