Rapid, sensitive and specific electrochemical detection of E. coli using graphitized mesoporous carbon modified electrodes

Abstract

Escherichia coli (E. coli) is a highly pathogenic bacterium causing infections to the human body primarily from a variety of sources including food intake. As per the World Health Organization (WHO), the mortality and morbidity rate due to E. coli is significantly high, approximately 8%. Therefore, a real-time, rapid, user-friendly and interference-free E. coli detection system offers great clinical importance. In this work, a highly sensitive, specific, and simple method of electrochemical detection of E. coli has been demonstrated. The electrochemical system employs the conventional three-electrode configuration, wherein glassy carbon (GC), chemically modified with graphitized mesoporous carbon (GMC), has been employed as the working electrode. While using platinum and Ag/AgCl as counter and reference electrodes respectively, voltametric techniques were applied to obtain the interference mitigated response of E. coli detection. The GCE/GMC electrode showed excellent sensitivity and selective response towards E. coliin a linear detection range of 2.52 × 103 CFU/mL to 25.2 × 104 CFU/mL and 252CFU/mL to 2268CFU/mL respectively with a limit of detection (LOD) of 50.40CFU/mL. Further, the developed system was tested for interference with other bacteria and real samples, such as pond water, tap water, and deionized water. Appreciable recovery values and negligible interference were observed. The prepared electrode demonstrated promising results towards efficient, real-time, and rapid E. coli detection.