FIGURE 5.

Interpretation of the bilayer disruption mechanism. Upon adsorption of the copolymer to a flat surface of an SPB, the PEG chains are compressed. This process is entropically costly, and the free energy of the system is lowered by bending the bilayer and lifting it off of the underlying substrate. The process involves bilayer rupture and is therefore thought to nucleate at pre-existing defects or be facilitated by osmotic and electrical gradients that destabilize the bilayer. When the disruption process is completed, most of the lipids are floating in solution in the form of worm-like lipid-PLL-g-PEG complexes. The copolymer also coats the SiO₂ substrate with the remains of bilayer.