Multiplexed Single-Cell Rheology Probing Using Surface Acoustic Waves.

Cellular rheological properties affect cell function and are reflective of cell status. It is challenging to perform multiplexed single-cell rheology probing with high controllability, particularly for adherent cells. A surface acoustic wave (SAW)-based method is presented for this purpose. The method integrates the potent micromanipulation ability of acoustic waves in a microfluidic chamber with the ability of cell-anchored microbeads to concentrate the acoustic energy to deform the cell. Two strategies are developed for placing a targeted microbead at a desired position on the cell membrane. The power-law rheological dynamics with plastic components are applied to fit the creep (during the mechanical loading) and relaxation (after force removal) responses of the cell. With more than 400 measurements of adherent cells and each with detailed dynamics, a full range of viscoelastic behaviors of cells far beyond the typical rheology of previously reported adherent cells and unexpected negative plastic compliance is observed. The developed method supports in-depth investigations of biomechanics at the cellular and subcellular levels, with considerable potential for extension to mechanical force-based cell function regulation.