Characterization of biomolecule immobilization by scanning force microscopy using a wet-masking technique

Abstract

The assemblage of molecular layers was investigated using scanning force microscopy (SFM). A wet-masking technique was used for the preparation of monolayers steps by partial masking of the substrate with an elastomeric mask during incubation in the modification buffers. The subsequent adsorption of biotin, streptavidin, and biotinylated beads onto a gold substrate was investigated by SFM visualization of the created steps. The molecular layers were characterized based on measurements of step height and surface roughness. The simultaneous visualization of the surface before and after modification minimizes artifacts introduced by changes in tip shape or imaging parameters.