An integrated wearable fluorescence sensor for E. coli detection in catheter bags

Urinary tract infections (UTIs), including catheter-associated UTIs (CAUTIs), affect millions worldwide. Traditional diagnostic methods, like urinalysis and urine culture, have limitations—urinalysis is fast but lacks sensitivity, while urine culture is accurate but takes up to two days. Here, we present an integrated wearable fluorescence sensor to detect UTI-related bacterial infections early at the point of care by on-body monitoring. The sensor features a hardware platform with a flexible PCB that attaches to a urine catheter bag, emitting excitation light and detecting emission light of E. coli-specific enzymatic reaction for continuous monitoring. Our custom-developed smartphone application allows remote control and data transfer via Bluetooth and performs in situ data analysis without cloud computing. The performance of the device was demonstrated by detecting E. coli at concentrations of 10⁰–10⁵ CFU/mL within 9 to 3.5 h, respectively, with high sensitivity and by testing the specificity using Gram-positive (i.e., Staphylococcus epidermidis) and Gram-negative (i.e., Pseudomonas aeruginosa and Klebsiella pneumoniae) pathogens. An in vitro bladder model testing was performed using E.coli-spiked human urine samples to further evaluate the device's practicality. This portable, cost-effective device has the potential to transform the clinical practice of UTI diagnosis with automated and rapid bacterial detection at the point of care.