title: Antibody adsorption and orientation on hydrophobic surfaces.
abstract: The orientation of a monoclonal, anti-streptavidin human IgG1 antibody on a model hydrophobic, CH(3)-terminated surface (1-dodecanethiol self-assembled monolayer on gold) was studied by monitoring the mechanical coupling between the adsorbed layer and the surface as well as the binding of molecular probes to the antibodies. In this study, the streptavidin antigen was used as a probe for the Fab portions of the antibody, while bacteria-derived Protein G' was used as a probe for the Fc region. Bovine serum albumin (BSA) acted as a blocking protein. Monolayer coverage occurred around 468 ng/cm(2). Below 100 ng/cm(2), antibodies were found to adsorb flat-on, tightly coupled to the surface and unable to capture their antigen, whereas the Fc region was able to bind Protein G'. At half-monolayer coverage, there was a transition in the mechanism of adsorption to allow for vertically oriented antibodies, as evidenced by the binding of both Protein G' and streptavidin as well as looser mechanical coupling with the surface. Monolayer coverage was characterized by a reduced level in probe binding per antibody and an even less rigid coupling to the surface.
authors.affiliation: Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stauffer III, Stanford, California 94305-5025, United States.
authors.forename: Meredith E
authors.initials: ME
authors.lastname: Wiseman
authors.forename: Curtis W
authors.initials: CW
authors.lastname: Frank
mesh_terms: D000327:Adsorption; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology; D006046:Gold; D057927:Hydrophobic and Hydrophilic Interactions; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry; D007074:Immunoglobulin G / Q000737:chemistry; D011485:Protein Binding; D058525:Quartz Crystal Microbalance Techniques; D011961:Receptors, Fc / Q000737:chemistry / Q000276:immunology; D012710:Serum Albumin, Bovine / Q000737:chemistry; D019809:Streptavidin / Q000737:chemistry / Q000276:immunology; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D011961:Receptors, Fc; D013438:Sulfhydryl Compounds; C013976:dodecylmercaptan; D012710:Serum Albumin, Bovine; D006046:Gold; D019809:Streptavidin