LIPOSOME AND PROTEOLIPOSOME FUSION ONTO SOLID SUBSTRATES, STUDIED USING ATOMIC-FORCE MICROSCOPY, QUARTZ-CRYSTAL MICROBALANCE AND SURFACE-PLASMON RESONANCE - BIOLOGICAL-ACTIVITIES OF INCORPORATED COMPONENTS

Stable lipid monolayers were deposited using the Langmuir-Blodgett technique onto silicon wafers, and were fused with liposomes containing acetylcholinesterase. The activity of the protein on the solid substrate was verified up to 28 days with a half-life of about 7 days. Atomic force imaging showed that the topography of the surface did not change significantly during this period. Liposomes containing the ganglioside G(M1) were fused onto modified gold surfaces using the same technique. The fusion process and binding of cholera toxin to the ganglioside were continuously monitored with a quartz crystal microbalance and by surface plasmon resonance. The fusion process resulted in an environment in which biological components retain their activity and, in combination with either one of the techniques used, may be the principle for membrane-based biosensors.