AFM for structure and dynamics of biomembranes.

We review structure and dynamic measurements of biomembranes by atomic force microscopy (AFM). We focus mainly on studies involving supported lipid bilayers (SLBs), particularly formation by vesicle rupture on flat and corrugated surfaces, nucleation and growth of domains in phase-separated systems, anesthetic-lipid interactions, and protein/peptide interactions in multicomponent systems. We show that carefully designed experiments along with real-time AFM imaging with superior lateral and z resolution (0.1 nm) have revealed quantitative details of the mechanisms and factors controlling vesicle rupture, domain shape and size, phase transformations, and some model biological interactions. The AFM tip can also be used as a mechanical transducer and incorporated in electrochemical measurements of membrane components; therefore, we touch on these important applications in both model and cell membranes.