Amperometric Monitoring of the Neuropeptide “Substance-P” Level in Biological Fluids

Abstract Presented here is a capillary enzyme immunoassay constructed on a foil-based microfluidic chip for rapid determination of Substance-P (SP) level in human plasma, serum and saliva. Using a competitive ELISA implemented into the capillary, the amperometrically detected SP by flow injection analysis was related to the percentage amount between SP standard (or sample) and SP-labelled glucose oxidase conjugate bound to the capture antibody. A detection limit of 10 pg/ml was obtained. The assay allows fast reading of diagnostically relevant levels. Producing reliable results comparable to microplate format, the immunochip sensor may have a significant impact in point of care diagnostics.