Diaper-embedded urinary tract infection monitoring system powered by a urine-powered battery

Urinary tract infection (UTI) is one of the most common infections accounting for more than 7 million office visits per year. Although mostly uncomplicated and easily treatable, if identified early, UTI can be a major source of morbidity and mortality in geriatric patients, in particular, those suffering from neurodegenerative diseases, and in infants who have difficulties in communicating symptoms, making early identification of UTIs crucial. In this paper, we present a diaper-embedded, wireless, self-powered, and autonomous UTI monitoring sensor module that allows an effortless early detection of UTIs. The sensor module consists of a paper-based colorimetric nitrite sensor, urine-powered batteries, a boost converter, a low-power sensor interface utilizing pulse width modulation (PWM), and a Bluetooth low energy (BLE) module for wireless transmission. Experimental results show a better detection of nitrite, a surrogate of UTI, than conventional dipstick testing. The sensor module achieves a sensitivity of 1.35 ms/(mg/L) and a detection limit of 4 mg/L for nitrite.