Imaging of cells with atomic force microscopy operated at a ‘‘tapping’’ mode

Abstract

This paper reports direct imaging of cells with a new scanning mode for atomic force microscopy (AFM), a tapping mode for AFM (TMAFM). Two kinds of cells, Escherichia coli (E. coli) and cultured hamster ovary (CHO) cells, prepared on indium tin oxide (ITO) glasses were observed in air. The TMAFM yielded very reproducible images without appreciable modifications of the sample surfaces. The images were examined in two modes of the data representation; normal height-mode and deflection-mode (similar to a first derivative of height-mode data) representations. The deflection-mode image of the E. coli sample showed much finer surface details than the conventional height-mode one, while the height-mode image of the CHO sample provided more detailed structure than the deflection-mode one.