BIOTIN-FUNCTIONALIZED SELF-ASSEMBLED MONOLAYERS ON GOLD - SURFACE-PLASMON OPTICAL STUDIES OF SPECIFIC RECOGNITION REACTIONS

The molecular recognition of biotin by the bacterial protein streptavidin at functionalized monolayers of mercaptans on gold was studied by surface plasmon spectroscopy and microscopy. It was found that the higher the packing density of the biotin labels in the monolayers was, the less effective was their binding ability. Low surface coverage and hence good accessability of the labels by the protein leads to very fast-diffusion controlled-docking of streptavidin to the surface, visible in a shift of the resonance angle.