Simultaneous On-chip Surface Plasmon Resonance Measurement of Disease Marker Protein and Small Metabolite

Abstract

Disease marker protein and a correction marker were simultaneously measured in a poly-dimethylsiloxane based microchannel. Two gold films in the microchannel were modified with antibody and redox polymer containing horseradish peroxidase (HRP). Creatininase, creatinase, and sarcosine oxidase were immobilized in the upstream. At first, marker protein and creatinine were simultaneously measured by surface plasmon resonance (SPR) and electrochemical methods, respectively. Then, we measured two analytes only by SPR method. We could measure glycoprotein, prostate specific antigen (PSA) (MW=33 kDa) and creatinine (MW= 113) both by SPR angle shifts caused by immuno- and redox reactions, indicating that urinary PSA concentration could be normalized with creatinine concentration by single injection.