Quantitative evaluation of visco-elastic distribution of living cells using scanning probe microscopy

将细胞迁移理解为一个完整的力学系统，需要对活细胞的力学特性进行实验研究。本文提出了一种利用SPM的力调制模式来测量活细胞刚度的方法，该方法具有较高的时间和空间分辨率。然而，在液体环境中，由力调制模式获得的细胞刚度往往是令人难以置信的，为了解决这个问题，一个微悬臂梁的一维动力学方程，考虑到样品的粘弹性和液体的粘度，进行了数值分析，以评估相移和振幅调制悬臂梁与液体中的活细胞接触时的关系。此外，振动分析时，悬臂梁周期性地接触和不接触的各种粘弹性样品的样品进行。在此基础上，导出了悬臂梁振动特性与试样粘弹性特性之间的定量关系。利用这些结果，新开发了活细胞粘弹性分析系统，并演示了活细胞的力学特性。

Understanding cellular migration as an integrated mechanical system requires an experimental investigations on mechanical properties of living cells. Force modulation mode with SPM is proposed as a useful method fur measuring stiffness of living cells with high temporal and spatial resolution. However, in liquid environment, cellular stiffness obtained by force modulation mode is often incredible.To clear this problem, numerical analysis of the 1-dimensional dynamic equation of a-micro cantilever, which concern about the visco-elastic property of the sample and viscosity of the liquid, is carried out to evaluate the relations between phase shift and amplitude modulations when the cantilever contacts with the living cells in a liquid. Also, the vibration analysis is performed when the cantilever periodically contact and not contact to the sample for various visco-elastic samples. Based on those results, the quantitative relations between vibration property of the cantilever and visco-elastic property of the sample are derived. Using these results, analysis system of the visco-elastic property for living cells is newly developed and the mechanical property of the living cells are demonstrated.