New stick-on sweat sensor offers a noninvasive way to monitor cholesterol and triglycerides (Photo – caltech.edu)
A team of researchers led by Caltech medical engineering professor Wei Gao has developed a wearable patch that could one day allow people to monitor cholesterol and triglyceride levels without a blood draw.
By News Desk
The stick-on device analyzes sweat and uses machine learning to estimate lipid levels in the blood. Researchers say the technology could eventually enable continuous monitoring of cholesterol and triglycerides, which are important indicators of cardiovascular and metabolic health.
Traditional lipid testing requires a blood draw followed by laboratory analysis. The new patch instead collects measurements from sweat. Because lipid levels in sweat do not directly correspond to those in blood, the researchers developed a causal machine-learning model that accounts for physiological factors such as body mass index, sex and sweating rate.
“Together, the sweat measurement and the causal machine learning model can predict the blood level with high accuracy,” Gao said.
The technology presented several challenges. Much of the cholesterol in sweat is found in a form called esterified cholesterol, which cannot be measured directly by the sensor. To address this, the researchers developed a two-step enzymatic process that converts esterified cholesterol into a measurable chemical signal.
The team also developed a system to maintain the supply of ATP, or adenosine triphosphate, needed to measure triglycerides. ATP was incorporated into a specialized polymer within the patch so it could be gradually released into sweat. Researchers reported that the system could sustain the ATP supply required for triglyceride sensing for more than 20 hours.
The researchers tested the wearable device on 24 participants in preclinical testing. Their findings were published in Nature Sensors in a paper titled “Non-invasive continuous lipid profiling via cofactor-refreshing cascading enzymatic reactions and causal machine learning.”
Gao said a noninvasive method for monitoring lipids could provide earlier warnings of cardiovascular or metabolic diseases, particularly because people do not routinely undergo blood testing.
Gao’s research group has previously developed wearable sweat sensors for glucose and uric acid. The new lipid sensor represents another step toward continuously monitoring substances that traditionally require laboratory blood tests.
The research involved scientists from Caltech and UCLA and was supported by the National Science Foundation, the National Institutes of Health, Samsung Research America and the Heritage Medical Research Institute.
The wearable patch remains a research-stage technology, but the findings point to the possibility of continuous cholesterol and triglyceride monitoring without conventional blood draws.
Read the full article at Caltech.edu.
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