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Ringing mode of atomic force microscopy (AFM) enables imaging the surfaces of biological samples, cells, tissue, biopolymers, etc. to obtain unique information, such as the size of molecules pulled by the AFM probe from the sample surface, heights of the sample at different load forces, etc. (up to eight different imaging channels can be recorded simultaneously, which is in addition to five channels already available in other rival modes). The imaging can be done in both air (gases) and liquid (buffers). In addition, the images obtained in ringing mode do not have several common artifacts and can be collected up to 20× faster compared to the rival imaging modes. Here we describe a step-by-step approach to collect images in ringing mode applied to biological and soft materials in general. Technical details, potential difficulties, and points of special attention are described.

Atomic force microscopy (AFM) indentation analysis of cells is a unique method of measuring stiffness of the cell body and physical properties of its pericellular coat. These cell parameters correlate with cells of abnormality and diseases. Viable biological cells can be studied with this method directly in a culture dish with no special preparation. Here we describe a step-by-step method to analyze the AFM force-indentation curves to derive cell mechanics (the modulus of elasticity of the cell body) and the parameters of the pericellular coat (density and the thickness of the coat layer). Technical details, potential difficulties, and points of special attention are described.

Fractal analysis of the cell surface is a rather sensitive method which has been recently introduced to characterize cell progression toward cancer. The surface of fixed and freeze-dried cells is imaged with atomic force microscopy (AFM) modality in ambient conditions. Here we describe the method to perform the fractal analysis specifically developed for the AFM images. Technical details, potential difficulties, points of special attention are described.