Investigation of work of adhesion of biological cell (human hepatocellular carcinoma) by AFM nano-indentation

In this study, we presented investigation of mechanical properties by AFM nanoindentation on human hepatocellular carcinoma cells treated with fullerenol for 24, 48 and 72 hours. Atomic force microscope was routinely used to investigate the morphology and biomechanical properties of living carcinoma cells, and adhesion phenomenon (negative force) was detected in the obtained force-displacement curves. Conventionally, Hertz contact model has been widely used for determination of cell elasticity, however this contact model cannot account for adhesion. Alternatively, JKR contact model, as expected for adhesion circumstance, was used to fit the obtained force-displacement curves, resulting a new parameter termed work of adhesion in addition to Young's modulus. The fitting results show that not only Young's modulus but also work of adhesion exhibit significant variation as the treatment period increases. The investigation suggests that work of adhesion may also serve as an effective bio-index to evaluate the effects of fullerenol or other anticancer agents on cancer cells, and provide insight into cancer progression.