A team of scientists from Nanyang Technological University, Singapore (NTU Singapore) has created a band-aid like plaster capable of measuring body biomarkers that can indicate health or disease via sweat, thus leading the way toward a non-invasive way to monitor patient health.

Because human sweat contains biomarkers like glucose, lactate and urea that can be indicators of assorted health conditions, the researchers sought to collect these in a non-invasive and painless manner, making it ideal for daily monitoring.

Source: NTU Singapore

To accomplish this, the team encapsulated microlasers in liquid crystal droplets and embedded the liquid within a soft hydrogel film, thereby creating a compact and flexible light-based sensing device. According to the researchers, the device is similar to plaster and offers accurate biomarker readings within minutes.

The microlasers are modified to detect three different types of biomarkers — lactate, glucose and urea — while a different colored liquid crystal dot on the plaster distinguishes each biomarker.

The team explained that when sweat from the wearer interacts with the plaster, the amount of light emitted by the microlasers alternates according to the concentration of biomarkers present. A light source is shone on the plaster so that the wearer can read the biomarker levels and the light emitted from the microlaser sensors is then analyzed and subsequently translated via a mobile app.

During trials of the technology, the plaster picked up minute fluctuations of glucose, lactate and urea levels in sweat down to 0.001 mm, which the researchers suggest is 100 times better than similar technology.

"Our device is capable of detecting both the high and low range of biomarkers levels. This is particularly beneficial for diabetic patients as current similar health monitoring devices focus on tracking only high glucose levels, but not abnormal or low glucose levels, which may indicate other health complications. In comparison, our device will provide a clearer picture of the users' health condition with a variety of readings captured," the researchers added.

Going forward, the team intends to modify the microlaser sensors so that they can detect a wider range of substances, such as drugs and other chemicals found in sweat.

The plaster is detailed in the article, “A Wearable Thin-Film Hydrogel Laser for Functional Sensing on Skin,” which appears in the journal Analytical Chemistry.