Oriented antibody biointerfaces on nanofibrillated cellulose materials

Bioaffinity attachment allows for oriented and homogenous attachment of proteins on surfaces. In this work the objective was to utilize physical adsorption together with specific bioaffinity of protein A for antibodies to immobilize specifically oriented antibodies on nanofibrillated cellulose (NFC) model surfaces. This approach utilizes the specific interaction of protein A of Staphylococcus aureus with the Fc portion of most IgG molecules of various species without disrupting the antigen recognition capabilities of the antibody. Protein A was adsorbed on unmodified NFC surface and on NFC surface with pre-adsorbed carboxymethyl cellulose (CMC). Anti-human IgG was subsequently adsorbed on top of the protein A treated unmodified and CMC-modified NFC surfaces. The human IgG recognition sensitivities of these prepared biointerfaces were compared to a system where anti-human IgG was directly adsorbed on unmodified NFC. The biointerface preparation and functionality on these NFC surfaces was also compared to similar biointerfaces prepared on regenerated cellulose model surfaces. The bioconjugation processes were characterized using surface sensitive techniques including Surface Plasmon Resonance technique, Atomic Force Microscopy and X-Ray Photoelectron Spectroscopy. By correlating the information provided by these techniques we gained insights into the physcochemical aspects paramount to biofunctionalizing the surface of nanofibrillated cellulose materials.