Bacteria-on-chip: a multiplexed point-of-care electrochemical platform for rapid detection of Escherichia coli and antimicrobial susceptibility testing

Abstract

Urinary tract infections (UTIs), primarily caused by Escherichia coli (E. coli), are among the most prevalent bacterial infections, affecting millions of individuals each year. Along with this, the rising prevalence of antibiotic resistance poses a major clinical challenge, underscoring the need for rapid and accurate pathogen identification and antimicrobial susceptibility testing (AST). However, conventional diagnostic methods are often costly, labour-intensive, and associated with long turnaround times. To address these limitations, this study presents a fully portable, smartphone-integrated, multiplexed electrochemical platform for the selective detection of E. coli DH5α and rapid AST. An indium tin oxide (ITO)-based three-electrode system functionalized with gold nanoparticles was used for sensitive detection of E. coli DH5α. The immunosensor was fabricated by immobilizing monoclonal antibodies (mAbs) specific to E. coli DH5α onto the functionalized gold surface. The platform achieved a limit of detection of 1.67 × 10⁷ CFU mL⁻¹, with a detection range from 2.76 × 10⁷ to 3.0 × 10¹⁰ CFU mL⁻¹. Notably, the detection time is 30 minutes, and the system allows simultaneous testing of four antibiotics within five hours, a substantial improvement over the 2–5 days required by standard AST methods. Furthermore, integrating microfluidic reservoirs with an on-chip heating module enables controlled bacterial incubation and real-time electrochemical detection. This compact handheld platform offers a rapid, sensitive, and multiplexed diagnostic solution to combat antimicrobial resistance.