CHARACTERIZATION OF BIOMOLECULE IMMOBILIZATION BY SCANNING FORCE MICROSCOPY USING A WET-MASKING TECHNIQUE

The assemblage of molecular layers was investigated using scanning for ce microscopy (SFM). A wet-masking technique was used for the preparat ion of monolayer steps by partial masking of the substrate with an ela stomeric mask during incubation in the modification buffers. The subse quent 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 o f step height and surface roughness. The simultaneous visualization of the surface before and after modification minimizes artifacts introdu ced by changes in tip shape or imaging parameters.