Fabrication of avidin single molecular layer on silicon oxide surfaces and formation of tethered lipid bilayer membranes

Abstract

Single molecular layer of avidin is fabricated on an atomically flat SiO2 surface and characterized by atomic force microscopy (AFM) and infrared reflection absorption spectroscopy. Immobilization of avidin is performed as follows; i) ester-modification of the surface by silane-coupling agent, ii) carboxylation by hydrolysis in HCl and iii) amide bonding between the surface -COOH and -NH2 in avidin molecules. Large dome structures (∼60 nm height) are formed after the ester-modification, but an atomically flat surface is obtained after the hydrolysis reaction. AFM topographs and function-recognizing images show that the each of avidin molecules adsorbs as a single molecule and retains the biotin-binding activity. Formation of a tethered bilayer membrane of a biotinylated phospholipid on the avidin layer is also described. [DOI: 10.1380/ejssnt.2005.237]