초록 |
Liposomes and proteoliposomes, artificial membranes, interact with many solutes such as drugs, peptides and proteins. Immobilization of (proteo)liposomes in gel beads or silica capillary surface by avidin-biotin binding has been appeared in recent papers[1, 2]. Assembly of the (proteo)liposome on gold surface is useful for membrane biosensors instead of planar lipid membranes. Anzai et al.[3] have recently constructed multiple polymer layers mediated by avidin-biotin binding and used quartz crystal microbalance (QCM) for measurement of the construction. The application principle of quartz crystal in the characterization of polymer film is based on the relation between the mass change of surface with elastic film and the resonant frequency shift of the quartz crystal. But the introduction of the new concept of resonant resistance[4-8] made us easily understood the viscoelastic change of polymer film of multiple layers besides mass change from the change of resonant frequency. Both the resonant frequency and resonant resistance can be simultaneously measured by using quartz crystal analyzer (QCA 917, Seiko EG&G, Japan). The resonant frequency - resonant resistance diagram (F-R diagram), whose relation is quantitatively represented in Fig. 1., can clarify the relation of mass and viscoelastic changes of the coated film. In this work, we demonstrate the method of using QCA to monitor the construction of five layers of unilamellar liposomes based on avidin-biotin binding on gold electrode of quartz crystal.
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