AFM Calibration of Nanofriction through Estimating Meniscus Water Membrane Contour between Single Polystyrene Nanoparticle and Silicon Surface In a certain humidity environment, the meniscus water membrane will greatly affect the nanofriction between the nanoparticle and the substrate in the process of AFM nanomanipulation. Herein, a mathematical model for estimating the meniscus water membrane contour using infinitesimal iteration is employed, then nearspherical polystyrene nanoparticles with radius from 50 nm to 300 nm were deposited on a silicon wafer for experiments using AFM after the tip is positioned and the friction between the nanoparticle and the substrate is measured. By analyzing the relationship between friction and effective contact area of water membrane and comparing with the existing work, the correctness and effectiveness of the method are proved.

Study of Virus Infection Procedure using Atomic Force Microscope This work mainly uses AFM to study the procedure of virus infecting cells and the mechanism of action of antiviral drugs. Firstly, the change trend of mechanical properties during cell apoptosis was studied, including normal cells and infected one by virus. The procedure of adhesion change was from soft to hard and then soft, in the same experiment. The Youngu0027s modulus was also measured under the same condition. Then the effect of virus dose on the process of infecting cells was studied. By quantitative analysis of the trend of mechanical properties, it was found that the change rate of the mechanical properties would speed up with the number of viruses infecting cells increasing. The quantity increase of the virus will accelerate the process of cell apoptosis. Finally, the antiviral drug Ribavirin inhibiting the process of virus infecting cells was studied by comparing the two designed experiments. The Ribavirin was found to modify the surface structure of the virus for inhibiting the virus infection.