Nanoparticle-assisted surface immobilization of phospholipid liposomes

Phospholipid liposomes (100-200 nm diameter) are deposited onto solid substrates after stabilizing them against fusion with the solid by allowing charged nanoparticles to adsorb at approximately 25% surface coverage. The immobilized vesicles remain stable over a period of days. Epifluorescence imaging shows that they diffuse freely over surfaces with the same charge but adsorb tightly onto surfaces with opposite charge. Nanoparticle adsorption to surface patterns of opposite charge provides a facile method to create large-scale surface-supported arrays of intact liposomes. This surface attachment method is simple chemically and applies generally for solid surfaces that can be hydrophobic or hydrophilic. Offering routes to localize proteins and other vesicle-contained objects at surfaces in tailored spatial patterns, these immobilized liposome arrays may find diverse applications in the emerging field of nanobiotechnology.