In Situ Atomic Force Microscope Imaging of Supported Lipid Bilayers

In situ AFM images of phospholipase A (PLA2) hydrolysis of mica-supported one- and two-component lipid bilayers are presented. For one-component DPPC bilayers an enhanced enzymatic activity is observed towards preexisting defects in the bilayer. Phase separation is observed in two-component DMPC-DSPC bilayers and a remarkable enhanced hydrolytic activity of the PLA2-enzyme for the DMPC-rich phase is seen. Furthermore, in a supported double bilayer system a characteristic ripple structure, most likely related to the formation of the Pβ′-ripple phase is observed.