Ag-Deposited Porous Silicon as a SERS-Active Substrate for the Sensitive Detection of Catecholamine Neurotransmitters

The sensitive detection of various neurotransmitters is very useful in diagnosing diseases related to the dysfunction of the neurotransmitter system. Surface-enhanced Raman scattering (SERS) is one of the best methods for bio-analyte detection as it provides a molecular fingerprint at a trace concentration level. In this study, Ag-deposited porous silicon (Ag@pSi) was fabricated as a SERS-active substrate via metal-assisted chemical etching and electroless plating methods. Dopamine (DA) and norepinephrine (NE) neurotransmitters were tested as probing analytes. The Ag@pSi substrate demonstrated the sensitive detection of the neurotransmitters (DA and NE) over the wide concentration range (from 10 ‒6 to 10 ‒10 M), with a good linearity between the intensity of specific Raman peak and the log-scale concentration. The Ag@pSi substrate also distinguished the individual analytes in a mixture of DA and NE at 10 ‒8 M, confirming the efficacy of the developed SERS substrate for the selective detection of neurotransmitters. Graphic Abstract