A Rapid Low Power Ultra-Violet Light-Assisted Bacterial Sensor for Coliform Determination

Abstract

Titanium dioxide (TiO 2 ) particle-incorporated Prussian blue (PB) sensor for the detection and inactivation of Escherichia coli ( E . coli ) is developed in this study. The system requires low power ultra-violet (UV) light to photoactivate TiO 2 particles and change of signal response is measured immediately upon irradiation using cyclic voltammetry. The generation of free radical species (OH . ) and H 2 O 2 from the oxidation of water by the hole ( h + ) are the main components which cause destruction of cell membrane and eventually result in the inactivation of cell. Our study also shows direct oxidation of cells by h + as one of the mechanisms for cell inactivation due to the close contact between TiO 2 particles and E . coli cells. Highly attractive features of this unique sensor include its ability to be regenerated and reused for at least three times without the use of harsh chemicals, good reproducibility and its specificity in bacteria sensing when tested against organic contaminants, which potentially reduce the operation cost when incorporated into water disinfection system. Its superior performance in detection of total coliform without additional steps of sample treatment is also demonstrated in river water. TiO 2 particle-incorporated PB membrane sensor exhibits signal response with higher current output compared to PB-TiO 2 coated screen printed carbon electrode (SPCE) due to its porous structure and higher surface area, suggesting its potential development into a powerful and low cost contamination monitoring tool.