The problem of Nonspecific Adsorption at Measurements in Blood Plasma with Surface Plasmon Resonance Biosensors
E. Brynda, C. Rodriguez Emmenegger, T. Riedel, Z. Sedlakova, M. Houska
Institute of Macromolecular Chemistry Academy of Sciences of the Czech Republic, v.v.i., CZ
Keywords: surface plasmon resonance biosensors, blood plasma, antifouling surfaces
Abstract:The work was aimed at feasibility of surface plasmon resonance (SPR) biosensors applicable in blood plasma. Deposition of human blood plasma and adsorption of human serum albumin (HSA), human IgG, and human fibrinogen from phoshate buffered saline was studied on SPR sensor surfaces coated with anti-fouling layers, such as, self-assembled monolayers (SAM) of alkanethiolates terminated with diethylene glycol, grafted carboxy terminated poly(ethylene glycol), zwitterionic polymer brushes, and covalently crosslinked HSA and antibody multilayers. The polymer layers decreased adsorption of the tested proteins more effectively than SAMs. There was no simple relationship between plasma fouling and adsorption of the main plasma proteins or the layer wettability measured by contact angle. No protein adsorption and no plasma deposition were observed on poly(carboxybetain). On the other hand, high plasma deposition was observed on poly(sulphobetain) and poly(phosphorylcholine) even though the adsorption of the main plasma proteins was very low and their wettability was the highest of the tested coatings. Kinetics of deposition from blood plasma samples obtained from different donors was markedly different. The immobilization of mouse, goat, or rabbit antibodies onto the layers impaired their anti-fouling properties. The effect was not observed when chicken antibodies were used.