LAUSR

Abstract The trace detection of neurotransmitters is very useful in the diagnosis of severe neuropsychiatric diseases such as Parkinson's, Schizophrenia, and Depression. Surface enhanced Raman scattering (SERS) is a prospective technique for the sensitive detection of analyte with molecular information. Herein, a porous silicon (pSi) template (so-called silicon nanowires) was prepared using a metal-assisted chemical etching process, and the pSi template was successfully embedded with plenty of nanosilvers. The nanosilver-embedded pSi (pSi@Ag) was employed as a SERS-active substrate to detect dopamine (DA) and serotonin (ST) neurotransmitters at ultralow concentrations. The optimized pSi@Ag substrate produced an excellent dynamic linear range over six orders of magnitude (from 10−6 to 10−12 M), as well as showing the picomolar detection limit of ~10−13 M. The substrate exhibited the comparable performance to the current state-of-the-art researches, probably because the SERS signals were generated from larger number of analyte molecules adsorbed on the internal silver nanostructures with porous layer. Furthermore, the pSi@Ag substrate distinguished the individual component in the mixture (DA and ST at 10−8 M) without any labelling, corroborating the reliable pSi@Ag substrate for the application to the actual biological fluid.