Attachment and phospholipase A(2)-induced lysis of phospholipid bilayer vesicles to plasma-polymerized maleic anhydride/SiO2 multilayers

This article describes a method by which intact vesicles can be chemically attached to hydrolyzed maleic anhydride films covalently bound to plasma-polymerized SiO2 on Au substrates. Surface plasmon field-enhanced fluorescence spectroscopy (SPFS) combined with surface plasmon resonance spectroscopy (SPR) was used to monitor the activation of plasma-deposited maleic anhydride (pp-MA) film with EDC/NHS and the subsequent coupling of lipid vesicles. The vesicles were formed from a mixture of phosphatidylcholine and phosphatidylethanolamine lipids, with a water-soluble fluorophore encapsulated within. Vesicle attachment was measured in real time on plasma films formed under different pulse conditions (plasma duty cycle). Optimum vesicle attachment was observed on the pp-MA films containing the highest density of maleic anhydride groups. Phospholipase A(2) was used to lyse the surface-bound vesicles and to release the encapsulated fluorophore.