Improvement of force modulation mode with scanning probe microscopy for imaging viscoelasticity of living cells

Abstract

We improved the force modulation mode with scanning probe microscopy (SPM) in order to make a quantitative evaluation of the viscoelasticity of living cells. Taking account of the viscosity of liquid medium, the vibration frequency of the cantilever was selected to be 500 Hz, and analysis of cantilever vibration was adopted for evaluation of the viscoelasticity of the samples. Consequently, we have succeeded in determining viscoelasticity distribution on living cells. The values of Young's modulus and the coefficient of viscosity vary from 10 to 50 kPa and from 20 to 40 Pa·s on a cell, depending on its internal cellular structure.