A SCANNING-TUNNELING-MICROSCOPY COMPARISON OF PASSIVE ANTIBODY ADSORPTION AND BIOTINYLATED ANTIBODY LINKAGE TO STREPTAVIDIN ON MICROTITER WELLS

An antiferritin antibody was either, (a) passively adsorbed to microwe lls or (b) biotinylated and immobilised to streptavidin coated microwe lls. Scanning tunnelling microscope (STM) imaging of these well surfac es coated with a platinum (95%) carbon (5%) coating (Pt/C) conductive layer showed a randomly oriented array of antibodies for passive adsor ption whereas for biotin-streptavidin immobilisation there was a more uniform and even distribution of antibodies on the well surface. On fu rther incubation with ferritin STM imaging showed that for passive ads orption approximately 5% of the surface was functional, while for the biotinylated antibody it was greater than 60%. The images presented in this paper show graphically the loss of functionality that occurs usi ng passive adsorption and, conversely, the preservation of antibody fu nctionality using the biotin-streptavidin linkage for antibody immobil isation. These results correlate well with the work of others in the f ield.