Investigating the potential of ZTO as an efficient and cheap SERS substrate for the identification of bacteria.

In recent years, Surface Enhanced Raman Spectroscopy (SERS) has been considered the best tool for the detection and identification of the least concentration of analytes and micro-organisms, such as bacteria. In this article, we have successfully obtained the SERS signal of Escherichia coli and Methylene Blue (MB) using Zinc Tin Oxide (ZTO) nanostructures as the SERS substrate. The ZTO SERS substrates were grown by a simple thermal evaporation method and annealed at various temperatures ranging from 600 to 800 °C before using them for bacteria identification. After the structural verification and morphological analysis using XRD and SEM, ZTO samples were used as SERS substrates for the detection of E. coli and MB by placing a drop of each solution on the ZTO. SERS data strongly identified the presence of MB and E. coli Raman peaks. Furthermore, it was found that intensity of signals (for both E. coli and MB) was found to be improved from SERS substrates that are pre-annealed at higher temperature. The intensity of Raman peaks for E. coli and MB was increased by 60 000 and 120 000 counts as the annealing temperature increased to 600 and 800 °C, respectively. An enhancement factor of 1.44 × 104 was observed for MB. Results obtained in this study indicate that zinc oxide based nanostructured SERS chips are potential candidates for rapid identification of many pathogens. [ABSTRACT FROM AUTHOR]