Development of an electrochemical-surface enhanced Raman spectroscopic (EC-SERS) sensor for bacterial screening

Abstract

The lack of efficiency of current methods for bacterial screening has prompted an increasing interest in developing a cost-effective, rapid and sensitive alternative for applications in all sectors of society. This project aims to explore a new detection platform for bacterial screening by coupling an applied electric potential with surface-enhanced Raman spectroscopy (SERS), a technique termed electrochemical surface-enhanced Raman spectroscopy (EC-SERS). The goal of using this technique is to improve upon the sensitivity and reproducibility of normal SERS to allow for rapid, point-of-need (PON) bacterial detection and identification. This project first shows the EC-SERS characterization of the commonly observed nucleotide breakdown products that dominate the SERS spectra of bacteria: adenine, guanine, xanthine, hypoxanthine, uric acid, 5’-adenosine monophosphate (AMP), and guanosine. This thesis work then concentrates on developing a sample preparation method to be used to study bacteria using EC-SERS for the first time. The results of this project demonstrate the improvement of the SERS spectra of both E. coli K-12 and B. megaterium bacteria obtained when an electric potential is employed, and highlights the great promise of EC-SERS for use as a fast and affordable bacterial screening method.