Bacteriophage-Gated Optical Sensor for Bacteria Detection

Bacterial infections significantly impact public health, and the growing threat of antimicrobial resistance underscores the urgent need for rapid and accessible diagnostic tools. This study presents a novel bacteriophage-gated sensor for the selective detection of <i>Escherichia coli</i>. The sensor utilizes sulforhodamine B as a fluorescent reporter dye encapsulated in mesoporous silica particles, with bacteriophages acting as gatekeepers. Upon interaction with <i>E. coli</i>, the bacteriophages detach from the silica surface, releasing the dye and producing a measurable fluorescence signal. The sensor demonstrated high sensitivity for <i>E. coli</i> detection, with a detection limit of 10¹ CFU/mL achieved within 5 min. Integrated into a Point-of-Care Testing device, the system aligns with ASSURED criteria, offering affordability, sensitivity, specificity, and ease of use. The fluorescence response is detectable even by the naked eye using a simple LED lamp, enabling nonprofessional operation. Validation with real water samples confirmed the sensor's accuracy, with results consistent with standard culture-based methods. This bacteriophage-gated sensor provides a low-cost, rapid, and reliable tool for bacterial detection with potential applications in environmental monitoring and clinical diagnostics.