Characterization of chemisorbed monolayers by surface potential measurements

Publisher Website
Google Scholar
Abstract
Chemisorption has been used to immobilize uniform, low-defect density monolayers of aminopropylsilane and of d-biotin on evaporated gold substrates. The quality of the monolayers has been confirmed by surface potential measurements and by copper decoration. Avidin has been immobilized to these monolayers by (i) crosslinking to the aminopropylsilane with glutaraldehyde and (ii) binding directly to the biotin ligand. The changes in surface potential observed during each immobilization step are shown to be related directly to the molecular structure of each chemisorbed layer. Significantly, when the avidin is immobilized on the biotin monolayer the tetrameric protein is orientated with one pair of biotin binding sites on the upper surface of the protein monolayer. This allows the bifunctional ligand, bisbiotin, to be bound to the protein giving the possibility of attaching further protein layers to form molecular organizates suitable for molecular electronic and molecular sensing applications.