‘Band-Aid’ Measures Glucose Levels in Sweat Using Microlaser Technology

Diabetic patients generally use invasive finger prick tests to monitor their blood glucose levels, requiring them to prick their fingers to collect a blood sample for testing with a portable glucose meter. An alternative involves sensor-based monitoring devices, which, while effective, are expensive, rigid, and need to be attached to the skin for extended periods. However, human sweat contains biomarkers like glucose, lactate, and urea, which reflect various health conditions and can be collected non-invasively and painlessly, making it an ideal medium for daily health monitoring. Scientists have now developed a new 'band-aid' or smart plaster that measures these biomarkers in sweat, offering a non-invasive and effective method for health monitoring.

A team of scientists from Nanyang Technological University in Singapore created the compact and flexible light-based sensing device, similar to a plaster, which can provide highly accurate biomarker readings within minutes. This device was created by embedding microlasers within liquid crystal droplets, which are then encapsulated in a soft hydrogel film. The microlasers are tailored to detect three specific biomarkers: lactate, glucose, and urea. Each biomarker is indicated by a differently colored liquid crystal dot on the plaster. As sweat interacts with the plaster, the intensity of light emitted by the microlasers changes according to the biomarkers' concentration levels. Users can read these biomarker levels by shining a light on the plaster, whereupon the emitted light is analyzed and interpreted through a mobile application.

In real-live experiments, the plaster successfully detected minute variations in the levels of glucose, lactate, and urea in sweat down to 0.001 millimeters (mm), achieving a sensitivity 100 times greater than existing similar technologies. The NTU team believes that their innovation, reported in the journal Analytical Chemistry, is the first wearable sensing device capable of measuring multiple sweat biomarkers with such high sensitivity and dynamic range. This high sensitivity allows for monitoring a broad range (from low to high) of biomarker levels, offering detailed insights into a patient's health status. Moving forward, the researchers plan to enhance the microlaser sensors to detect a wider variety of substances, including drugs and other chemicals present in sweat.

“Our device is capable of detecting both the high and low range of biomarkers levels,” said NTU PhD candidate Nie Ningyuan. “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.”

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