Effect of a lipolytic enzyme on wettability and topography of phospholipid layers deposited on solid support

The wetting properties of solid supported phospholipid DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) films transferred by means of Langmuir–Blodgett and Langmuir–Schaefer techniques on hydrophilized glass from the surface of pure water, before and after modification with enzyme—phospholipase A₂ (PLA₂), were investigated.

The surface free energy (wettability) of the films was evaluated on the basis of contact angle measurements of three probe liquids (water, formamide, diiodomethane). The film structure of the lipid layers was examined using atomic force microscope (AFM). The AFM images appeared to be helpful for better understanding of the free energy changes caused by the enzyme PLA₂ action. The energy changes indicate that at room temperature DPPC mono- and bilayer is degraded within 5–10 min.