Amperometric microbiosensor as an alternative tool for investigation of D-serine in brain

This paper discusses the application of a reagentless, selective microbiosensor as a useful alternative tool for monitoring d-serine in neural samples. The main components of the 125-mu m-diameter disk biosensor were d-amino acid oxidase for d-serine sensitivity (linear region slope, 61 +/- A 7 mu A cm(-2) mM(-1); limit of detection, 20 nM), and poly-phenylenediamine for rejection of electroactive interference. The response time of the biosensor was of the order of 1 s, ideal for 'real-time' monitoring, and detection of systemically administered d-serine in brain extracellular fluid is demonstrated. Exploitation of this probe might resolve queries involving regulation of d-serine in excitotoxicity, and modulation of N-methyl-d-aspartate receptor function by d-serine and glycine in the central nervous system.