Biomechanical Properties Of Tumor Cells On Different Stiffness Substrates By AFM

The occurrence of tumor diseases is related to the increase of extracellular matrix(ECM)stiffness.When cells perceive the stiff changes of extracellular environment,they will have different biological responses.Different cellular biological behaviors will affect the development of cancer diseases.Therefore,the effect of substrate stiffness on the cellular biological behavior needs to be further studied.In this study,atomic force microscopy(AFM)and optical imaging were used to investigate the effects of substrate stiffness on the biomechanical properties of cancer cells with different malignancies.Firstly,several polyacrylamide(PAM)hydrogel substrates simulating physiological stiffness of normal and pathological tissues were selected according to the difference of cellular biological behavior on the substrate with different stiffness.The mechanical property of these substrates were characterized by AFM.Secondly,with the help of finite element analysis,the viscoelastic properties and spreading behavior of tumor cells on substrate with different stiffness were observed by AFM and optical imaging.And then we compared the mechanical responses of benign and malignant cells.The results showed that the mechanical sensitivity response and spreading behavior of malignant cells were more lagged than benign cells,which led to the phenomenon that malignant cells were softer than benign cells on stiff substrates.Finally,we constructed a three-dimensional cellular model and combined with fluorescence imaging to explore different cellular ability in forming microfilament on substrates with different stiffness.The results showed that the concentration of microfilament was positively correlated with the mechanical properties of cells.And the mechanical response of tumor cells mainly depends on the ability of cells to form cytoskeleton structure,which means with the change of substrate stiffness,the ability of malignant cells to generate skeleton structure is lower than benign cells.These results are helpful to differentiate benign and malignant cells and suggest that the lack of cellular mechanical response may be related to thedevelopment of cancer diseases.