AFM as a tool to probe and manipulate cellular processes.

The exploration of molecular processes governing physiological functions has significantly benefited from the emergence of novel nanoscaled techniques. Atomic force microscopy in force measurement mode can be used to investigate a multitude of cellular events in individual living cells with great sensitivity. Precise regions of the plasma membrane can be examined in relation to particular signalling pathways activated by a mechanical stimulus. Similarly, subtle cellular movements induced by biochemical activation of specific membrane receptors can be detected in real time with excellent temporal and spatial resolution. The possibility to challenge locally and mechanically cell surface receptors also provides information on the control exerted by a cell over individual adhesion sites. Overall, this information is vital for an in-depth understanding of mechanisms related to cellular movement and morphological regulation. Lastly, atomic force microscope-based nanomanipulations on living cells have recently been proposed as a tool to influence and monitor cellular homeostasis by introducing specific molecular entities into or extracting them from the cytoplasm of individual cells. This review provides detailed examples on how such atomic force microscopy experiments can be conducted to investigate processes relevant to cell physiology.