Doctors routinely ask for urine tests for a very good reason: they just work. A urine analysis can reveal essential basic information about a patient’s health and can be used to detect a wide range of common conditions and diseases. Even plainly visible changes in color, odor, and the amount of urine can indicate whether something is wrong.

The only problem with urinalysis is that it can take a while for results to come back from the lab. Paper strips can be a useful alternative, but the fast result time typically comes at the cost of low sensitivity.

Researchers in China have something else in mind. They’ve developed a flexible sensor that can provide-real time analyses for incontinent, elderly, or infant patients. One immediate application, for instance, is to incorporate the sensor into diapers, which would then send test results immediately as they get wet via Bluetooth.

Smart diapers

Xi Xie and Hui-Jiun Chen from Sun Yat-Sen University wanted to develop a wearable device that can both accurately and sensitively measure the concentration of several important health markers from urine while providing instantaneous feedback. They settled for a flexible electrode array no larger than a U.S. quarter.

Inside the array, the engineers included five different electrodes, each tuned to detect biomarkers such as potassium ions, sodium ions, hydrogen peroxide, uric acid, and glucose.

These can indicate various conditions and health statuses. Monitoring spikes and dips in urine glucose levels, for example, can be critically important for diabetes patients.

The sensors were connected to a tiny circuit board that has a Bluetooth module to communicate test results to a phone or computer, as well as a low-power lithium-ion battery to provide energy.

Researchers tested their prototype on urine from three volunteers, and they found the readings were up to par with commercial urine test systems commonly found in medical labs.

When they incorporated the flexible sensors into a diaper and dropped some urine on it, finding they could get readable signals for the biomarkers.

As a caveat, the researchers acknowledge that in a real-world setting, such ‘smart’ diapers would become slowly saturated with urine due to prolonged use, so the sensors would probably have to take multiple measurements to record stable readings.

The costs involved with incorporating electronics into disposable diapers may also prove to be prohibitive, although there’s always a market out there for virtually any product. For those who really need near real-time urinalysis, this device could provide a quick and painless alternative to cumbersome trips to the lab.

The findings appeared in the journal ACS Applied Nano Materials.