A Shear horizontal surface acoustic wave biosensor for a rapid and specific detection of d-serine

d-serine is an amino acid that has an important role in the regulation of N-methyl-d-aspartate (NMDA) signalling in the central nervous system. In fact, it acts as an endogenous co-agonist molecule for the NMDA receptor activation. Since an abnormal body level of d-amino acids is usually associated to different neurological diseases, it appears evident that it is of high interest to develop a fast and specific biosensor for the determination of d-serine. In this work, we report on the design and development of a surface acoustic wave (SAW) biosensor to detect the level of d-serine. The SAW-biosensor is based on the utilization of an inactivated form of the d-serine dehydratase isolated from Saccharomyces cerevisiae, a biomolecule that is able to specifically bind d-serine. In particular, we produced a PLP-reduced d-serine dehydratase biomolecule that was still able to bind d-serine and not to transform it into the product. The binding event between the "inactivated" d-serine dehydratase and d-serine was monitored by SAW delay-lines.