Physics of living systems

Understanding the behaviour of almost any biological object is a fundamentally multiscale problem — a challenge that biophysicists have been increasingly embracing, building on two centuries of biophysical studies at a variety of length scales.

It may look like little more than slime, but the glycocalyx coating our cells plays a key role in cell signalling. And changes to its physical structure have been linked to cancer, triggering emergent behaviours that form the focus of this Review.

Robust and responsive, the surface of a cell is as important as its interior when it comes to mechanically regulating form and function. New techniques are shedding light on this role, and a common language to describe its properties is now needed.

The behaviour of cells and tissues can be understood in terms of emergent mesoscale states that are determined by a set of physical properties. This Review surveys experimental evidence for these states and the physics underpinning them.

Evidence that ants communicate mechanically to move objects several times their size has prompted a theory that places the group near a transition between uncoordinated and coordinated motion. These findings and their implications are reviewed here.