抄録
Development of the biointerface for high performance immuno-sensing methods is one of the current research topics in analytical chemistry and biochemistry. We developed histidine-tagged protein A (His6-protein A)/poly(ethylene glycol) (PEG) co-immobilized gold surface as a new class of immuno-sensor chip, where both protein A and PEG are directly immobilized on the surface by the histidine-tag and the thiol group, respectively. In this study, the resulting surface was applied to sandwich assay for specific protein detection based on surface plasmon resonance measurements. Despite the similar content of immobilized antibodies, the amount of secondary antibody on His6-protein A/PEG surface was about eight times higher than that of physically adsorbed antibody/PEG surface. In addition, nonspecific protein absorption was extremely suppressed on His6-protein A/PEG surface, compared with Ni2+ -nitrilotriacetic acid (NTA) surface, which was generally used for the immobilization of histidine-tagged proteins. These results clearly indicate that effective orientation of the immobilized antibody with the prevention of non-specific adsorption was achieved on the His6-protein A/PEG surface.
