DIRECT OBSERVATION OF IMMUNOGLOBULIN ADSORPTION DYNAMICS USING THE ATOMIC FORCE MICROSCOPE

Atomic force microscopic images of a murine antifluorescyl monoclonal antibody (IgG 4-4-20) depositing from solution onto freshly cleaved mica were observed in real-time. These images clearly indicate a cooperative adsorption process, not a random one. Only IgG aggregates formed stable deposits, whereas isolated molecules desorbed readily from the surface. Subsequent adsorption occurred adjacent to the aggregates, forming ridges, and eventually a near monolayer was produced. Additional layers deposit only after the initial monolayer adsorption was nearly complete. Desorption of the IgG molecules in a distilled water medium was not observed. © 1990, American Chemical Society. All rights reserved.