A wearable self-powered biosensor system integrated with diaper for detecting the urine glucose of diabetic patients

Abstract

• The diaper alarm device was truly self-powered without any external power source. • The biosensor system composed of EBFC, PMS and LED enabled to detect the glucose level in urine of diabetic patients on-line. • The result was intuitive by LED flicker frequency which was proportional to the glucose concentration. In this paper, a flexible self-powered biosensor system integrated with the diaper was reported to detect the composition of urine. The system was powered by an enzymatic biofuel cell (EBFC), which used the glucose in urine as fuel to generate electricity. The EBFC was assembled in a diaper and connected with a power management system (PMS) possessing a capacitor as an energy storage device to drive a light emitting diode (LED) flashing. The frequency of LED flicker was proportional to the charging speed of the capacitor, which was determined by the generated power of EBFC. Therefore, the flashing of LED enabled to indicate the glucose concentration in urine when someone was wearing the diaper with EBFC. The biosensor system composed of EBFC, PMS and LED, was a self-powered sensor system without external power and enabled to detect the glucose level in urine of diabetic patients. In the process of experiment, the power density of EBFC could be up to 220 μWcm −2 in 5 mM glucose solution. In the range of 1–5 mM, the flashing frequency of LED was proportional to the glucose concentration (r = 0.994). Uric acid and carbamide were added to the sensor as interferences, and the results showed that it had good anti-interference ability. Obviously, the self-powered biosensor hold the potential application to warn the urine glucose level of diabetic patients with urinary incontinence.