9.11 - Mechanical Interactions between Cells and Tissues

Biology is based on polymers, namely proteins, carbohydrates, lipids, and nucleic acids such as DNA, both inside cells and outside cells. The physical nature of these soft and wet polymers has major implications for cell structures, properties, and functions. Indeed, within a multicellular organism, the organization of cells requires that each cell assess its relative location, taking in multiple cues from its polymeric microenvironment. Given that extracellular matrix (ECM) consists of the most abundant proteins in animals and contributes both structure and elasticity to tissues, ECM is likely to provide some key physical cues to cells. As a cell engages matrix and actively probes, it senses in deformation the local elastic resistance of ECM and nearby cells, and – like the proverbial princess who feels a pea placed many mattresses below – the cell seems to possess feedback and recognition mechanisms that even establish how far a cell can feel. Recent experimental findings and computational modeling of cell and matrix mechanics are summarized here and lend insight into the wide-ranging senstivities of cells to polymer mechanics.