Mechanical properties of single cells: Measurement methods and applications

Cell mechanical properties, e.g. elastic and shear modulus, play vital roles in cell activities and functions, such as cell growth, cell division, cell motion, and cell adhesion. Measurement of single-cell mechanical properties has attracted great interest from both academia and industry, due to its importance in a variety of applications, such as cell separation, disease diagnostics, immune status analysis and drug screening. Therefore, accurate, robust and sensitive methods for measuring the mechanical properties of single cells are highly desired. In this review, we classify ten most commonly used methods for measuring single-cell mechanical properties into three main categories based on measurement locations, (1) cell surface (2) cell interior and (3) whole cell, and discuss their utilizations with examples. In addition, we discuss directions for future research, such as improving throughput, automating the probing of cell mechanical properties and integrating different methods to achieve simultaneous measurements of mechanical properties of both cell surface and interior. The above are all necessary to overcome the limitations of current technologies in the mechanical characterization of single cells.