Investigating the mechanical properties of soft biological samples on the single-cell level is of great interest as cell mechanics play a central role in many physiological processes in health and disease. Scanning ion conductance microscopy (SICM) is an emerging technique for measuring cell stiffness on the micro- and nanometer scale in a non-contact fashion. However, as SICM stiffness measurements are based on a localized deformation of the sample, they are affected by the thickness of the sample. We found experimentally and numerically that the apparent stiffness of a thin sample is overestimated. We present a straightforward correction method to account for this effect and derive a thickness-dependent, multiplicative correction factor, which we apply to SICM stiffness mapping of living cells. The correction method allows us to quantitatively measure the stiffness of thin samples with SICM and is, therefore, essential for the comprehensive application of SICM to nanomechanical measurements.

中文翻译：

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有限样品厚度对扫描离子电导显微镜刚度测量的影响

在单细胞水平上研究软生物样品的机械特性非常有趣，因为细胞力学在健康和疾病的许多生理过程中起着核心作用。扫描离子电导显微镜 (SICM) 是一种以非接触方式在微米和纳米尺度上测量细胞刚度的新兴技术。然而，由于 SICM 刚度测量基于样品的局部变形，因此它们受样品厚度的影响。我们通过实验和数值发现，薄样品的表观刚度被高估了。我们提出了一种直接的校正方法来解释这种影响，并得出一个厚度相关的乘法校正因子，我们将其应用于活细胞的 SICM 刚度映射。