Drop-coating deposition surface-enhanced Raman spectroscopy on silver substrates for biofluid analysis

Utilization of surface-enhanced Raman spectroscopy as a measurement technique is of particular interest in biodetection due to its superb chemical specificity and high sensitivity. The use of SERS substrates further improve this method by massive enhancement of the molecule Raman spectrum, permitting very low levels of detection. Therefore it is important to seek for new ways to develop reliable substrates, which are quickly and easily manufactured at a low cost. This paper describes the development of a simple and cost-effective substrate for the SERS detection. The substrate is synthesized from a silver ink on the glass, and its utilization for biodetection is shown. The hydrophobicity of the substrate permits the pre-concentration benefit of the drop-coating deposition, by the formation of the coffee-ring. This allows to achieve lower limits of detection, by effectively measuring areas with higher concentration of measured molecules than the initial sample. However, the different properties of the medium, such as the influence of protein types and amounts, may influence the ring formation mechanics, thus effectively changing the pre-concentration of the target analyte.