Fabrication of protein-anchoring surface by modification of Sio2 with liposomal bilayer

SiO2 surface was successfully modified with phospholipid bilayer for biocompatibility by covering the planar surface with vesicular liposomes. By applying heat to rupture the vesicle, they were converted into a planar form. To effectively decorate the bilayer with biological molecules such as a protein, BAM (biological anchor for membrane) was used as a linker. It is a linear assembly consisting of oleyl chain, polyethylene glycol, and NHS (N-hydroxysuccinimide). After a target protein (BSA) was conjugated with BAM by NHS replacement, the conjugate was effectively inserted to the phospholipid bilayer through the lipophilic interaction between the oleyl chain and the lipid bilayer. The entire process was monitored and quantitatively analyzed by QCM (quartz crystal microbalance). BSA–BAM conjugate showed approximately 12-fold higher binding efficiency to the lipid bilayer than BSA alone. From this result, we conclude that SiO2 surface could be modified to a lipid bilayer surface so as to anchor a protein by the action of BAM.