A glassy carbon electrode modified with gold decorated iron oxide/ carbon dots for light assisted voltammetric detection of antibiotic resistant microbe Enterococcus faecalis

Detecting bacteria is essential in managing significant health concerns as it enables timely intervention, reducing complications and improving patient outcomes, particularly in treating common infections that necessitate precise identification for effective symptom management. Enterococcus species represent a notable threat in hospital-acquired infections and urinary tract infections (UTIs), given the increasing prevalence of strains resistant to multiple antibiotics, unresponsive to standard therapies, and carrying various virulence factors. Traditional approaches to identifying Enterococcus faecalis ( E. faecalis ) have limitations, including prolonged processing times, limited sensitivity, and the potential for false positive results. While Polymerase Chain Reaction (PCR) is a valuable tool, it is susceptible to contamination and variations in DNA concentration. The emerging technique of Photoelectrochemical (PEC) holds promise for enhancing E. faecalis detection by leveraging photogenerated electrons and holes. This study introduces a rapid and precise approach utilizing a light-assisted electrochemical biosensor featuring a glassy carbon electrode modified with a nanocomposite of gold-coated iron oxide and carbon dots (Au@Fe 3 O 4 /CDs). The nanocomposite was successfully synthesized and underwent thorough characterization. The investigation has a detection range from 1 to 14 CFU mL −1 , along with a notably low limit of detection (LOD: 3 CFU mL −1 , LOQ: 10 CFU mL −1 ). Rigorous examination of real-world samples such as food, water, and soil demonstrated exceptional specificity, reproducibility, and long-term stability of the sensor. The applications of the Au@Fe 3 O 4 /CDs nanocomposite in PEC processes underscore the potential of this innovative approach in addressing health concerns associated with bacterial infections and delivering real-time impacts for both healthcare and environmental domains. • Au@Fe3O4/CDs nanocomposite synthesized via simple hydrothermal and oxidation methods. • Au@Fe3O4/CDs/GCE is ecofriendly, photo-effective, and shows great repeatability and stability. • Photosensor demonstrates excellent performance with a very low detection limit of 3 CFU/mL. • The photoelectrocatalyst shows high selectivity (221.226 μA/CFU mL) amid interfering substances. • Ideal for onsite analysis of Enterococcus faecalis in spoiled food, water, and soil samples.