Probing recognition process between an antibody and an antigen using atomic force microscopy

Specific recognition interaction between human serum albumin (HSA) antigen and its associated antibody has been investigated by probing with atomic force microscopy. The interacting tip and surface was chemically modified to covalently bond the proteins to both an AFM tip and a flat surface. This ensured that the proteins bound to the tip surface did not unbind upon interaction. Chemical modification was achieved by initially silanising the glass surface with aminopropyltrimethoxysilane to activate the surface to support immobilisation and then the addition of gluteraldehyde which acts as the bridging agent between the solid support and the protein to be immobilised. The force-distance profiles were taken in aqueous solutions. The force-distance profiles between the antigen antibody show a strong attractive interaction, with a binding force of similar to - 2000 pN. (C) 1998 Elsevier Science B.V.