A wristwatch that can check blood sugar levels from sweat in real time has been developed by the Metallurgy & Materials Science Research Institute at Thailand’s Chulalongkorn University.

It’s accurate, not painful, less expensive and can replace imported equipment, and is expected to be available on the market soon.

The wristwatch can measure blood glucose and lactate levels from sweat. It has received a Good Invention Award for Science & Pharmacy, 2021, and a collaboration with the National Science & Technology Development Agency (NSTDA).

“Medical reports indicate that the level of glucose in sweat is directly related to blood sugar,” said Natnadda Rodthongkam, deputy director of the Metallurgy & Materials Science Research Institute. “So, we used this finding to innovate a device that helps tell the patient’s glucose level in real time. This is very important to the daily life of diabetic patients who must regularly monitor and control their blood sugar levels. Moreover, it helps reduce the burden of healthcare workers. Patients do not have to waste money and time travelling to the hospital and risk complications.”

Diabetes is a common disease among the elderly. According to the Diabetes Association of Thailand’s report in 2020, up to five million Thai people suffer from diabetes. More importantly, diabetic patients also experience muscle weakness caused by the disorder of the immune and nervous systems.

Currently, the methods used to determine blood sugar level are by drawing blood from the fingertips according to the fasting plasma glucose standards for diabetics, together with a lactate test to measure the concentration of lactate. Patients with muscle weakness need to fast for at least one hour before they can draw blood.

“Knowing real-time blood sugar and lactate levels will help patients take care of themselves, adjust their behaviour, or seek immediate medical attention before it becomes dangerous,” said Rodthongkam. “We therefore devised a method that is faster, more accurate, and doesn’t need fasting or drawing blood.”

This Chula-NSTDA joint project has researched and developed a yarn material that is biochemically modified to absorb sweat and is sensitive to glucose and lactate enzymes in a single device. Diabetics can monitor their blood glucose and lactate level anytime while wearing this smartwatch.

“This special yarn transmits the obtained data to a test sheet inserted inside the smartwatch case to compare the measurement against a standard calibration curve,” said Rodthongkam. “If the blood glucose is low, the colour will be light, if high, the colour will be dark, while the lactate value will appear even darker in colour.”

Currently, the research team is testing the effectiveness of the watch on diabetics and weak muscles, with cooperation from physicians specialising in diabetes treatment and the Comprehensive Geriatric Clinic at King Chulalongkorn Memorial Hospital. After successful testing to ensure its performance, this device will be developed to be used by real diabetic patients soon. The team also anticipates that this smartwatch will be popular among patients, and can help reduce the cost of importing high-priced medical devices from abroad.