Rapid and highly sensitive detection of bacterial pathogens using AgSnO/Si chip

Abstract

Surface-enhanced Raman scattering (SERS) is an important technique for detecting and identifying various chemical and biological species. In this study, we developed a low-cost, uniform, and stable SERS chip based on AgSnO/Si nanostructures for the detection of Tuberculosis (TB) and E. coli bacteria. We demonstrate that the post-annealing temperature significantly impacts the crystallinity, surface morphology, and resulting Raman signal of the chip. The highest enhancement in the Raman signal was achieved at a post-annealing temperature of 800 °C with more than ten times higher enhancement than that on a glass substrate (around 1622cm-1). This improved performance can be attributed to enhanced carrier concentrations in the host SnO due to oxygen related donor defect sites and a large surface area for adsorption due to the rough surface morphology of the AgSnO/Si chip. Further, the stability of the chip was confirmed by reproducing the same results after 12 months, and uniformity through identical Raman signals from different parts of the substrate. Hence, we demonstrate that rapid and accurate detection of bacterial pathogens is possible with a cost-effective AgSnO/Si chip.