Precision of cell-to-cell variation in power-law rheology characterized by atomic force microscopy

Abstract

The mechanical properties of compliant single cells are significantly associated with various cell functions. It is thus crucially important in the identification and sorting of cells to characterize not only the complex moduli that exhibit power-law rheology but also the cell-to-cell variation at the single cell level. Atomic force microscopy (AFM) can be used to measure cellular mechanical properties and to quantify cell-to-cell variation. However, less is known about how precisely and routinely the cell-to-cell variation is obtained when the complex moduli vary substantially in different cell samples. Here, we investigate the storage modulus G′ for single cells measured at controlled positions by AFM. We find that the spatial dependence of the frequency-dependent component of the cell-to-cell variation is preserved even if the spatial heterogeneity of G′ is changed with the cell sample. The invariance of the frequency-dependent cell-to-cell variation indicates the robustness of AFM for the mechanical diagnosis of single cells.