Nano-Scale Characterization of Surface Enhanced Raman Spectroscopic Substrates

Abstract

Surface Enhanced Raman Spectroscopy is fast gaining popularity as a technique for diagnosing diseases. From the biomedical perspective, the advantages of SERS include amount of sample for analysis is minimal; preparation for spectroscopy is minimal; analysis is simple and fast; test is non-destructive and easily reproducible. However the quality of Raman spectra obtained from SERS analysis is highly dependent on the substrate types. Characteristics of an ideal SERS substrate are maximum intensity enhancement, less deviation in enhancement, stable for a long shelf time and clean enough to study weak adsorbates. This paper describes the characterization of SERS substrates for salivary based analysis. The nano-scale characteristics of two SERS substrate types are compared against a Raman substrate using AFM, FE-SEM and Raman spectrometer. Enhancement to the analyte peak intensity is found with Klaritë and gold substrates. Both depicts background peaks in common at raman shift of 330cm-1, 412 cm-1, 526cm-1, 636cm-1, 688 cm-1, 1344 cm-1, 1538 cm-1 and 2784cm-1. The peak intensity of Klaritë is higher than gold substrate at all Raman shifts mentioned. For salivary based analysis, since the concentration of analyte will be low, Klaritë and gold coated slide is considered better substrate than quartz slide.