AVS 57th International Symposium & Exhibition
    Biomaterial Interfaces Thursday Sessions
       Session BI-ThP

Paper BI-ThP12
Adsorption of a Therapeutic Monoclonal Antibody on Surfaces Characterized by X-Ray Photoelectron Spectroscopy and Atomic Force Microscopy

Thursday, October 21, 2010, 6:00 pm, Room Southwest Exhibit Hall

Session: Biomaterial Interfaces Poster Session
Presenter: K.L. Steffens, National Institute of Standards and Technology
Authors: K.L. Steffens, National Institute of Standards and Technology
J.R. Wayment, National Institute of Standards and Technology
Correspondent: Click to Email
As the number of FDA-approved monoclonal antibody therapeutics increases, the need to understand and control aggregation and surface adsorption of these therapeutics becomes more critical. Aggregation of protein therapeutics is a concern, because aggregates may lead to serious immunological responses in patients. Currently, the cause of protein aggregation is not clearly understood. Recent evidence from several studies has suggested that the interaction of proteins with surfaces may influence solution phase aggregation processes. Therefore, investigation of these effects is critical in order to reduce or eliminate aggregation in biopharmaceutical products. In this study, we investigate the interaction of Rituxan™, a therapeutic monoclonal antibody, with various surfaces including alkanethiol self-assembled monolayers on gold, polyethylene glycol on gold, gelatin on gold, and bare glass. Both as-prepared and heat-stressed (aggregated) protein solutions were investigated with size exclusion chromatography (SEC) before and after contact with the surfaces to measure the presence of small antibody aggregates (monomers to trimers). The presence of larger antibody aggregates formed in solution was assessed by performing AFM of protein solutions deposited and dried on mica. Protein adsorption on the various surfaces was measured using x-ray photoelectron spectroscopy (XPS) to probe the surfaces before and after exposure to the protein solutions. In addition, the standard overlayer model was used to estimate the thickness of adsorbed protein layers. Results show that adsorption of the protein is highly dependent on the surface character as well as on the presence of solution phase aggregates.