A battery-free sweat sensor could enable quicker, more personalized monitoring of levodopa levels in people with Parkinson’s disease.
For people living with Parkinson’s disease, the benefits of a levodopa dose can sometimes wear off suddenly, causing movement difficulties to return before the next dose is due. To address this challenge, engineers and neuroscientists at the University of California San Diego developed a soft fingertip patch that continuously monitors levodopa levels in sweat without using a battery. During clinical testing, the sensor produced results comparable to conventional laboratory blood tests.
Published in Proceedings of the National Academy of Sciences, the technology could help doctors adjust medication schedules more quickly and precisely while allowing patients to monitor their treatment from home.
Levodopa remains the standard treatment for Parkinson’s-related motor symptoms, but maintaining the right medication level can be challenging. Insufficient medication can make movement difficult, whereas excessive doses may trigger severe involuntary movements. In the early stages of Parkinson’s, a single dose can work for several hours. As the disease advances, however, the period during which the medication provides effective symptom control may narrow to roughly two hours.
Doctors currently rely heavily on patient diaries to track when symptoms reappear and determine whether medication adjustments are needed. However, these self-reported records can be subjective and incomplete, potentially overlooking dangerous periods when levodopa levels fall between doses. The wearable patch offers a different approach by continuously tracking levodopa concentrations in the body and delivering real-time data.
Personalized medication dosing could soon be managed from home
The study was led by Tamoghna Saha, a postdoctoral researcher in Joseph Wang’s laboratory at the Aiiso Yufeng Li Family Department of Chemical and Nano Engineering at the UC San Diego Jacobs School of Engineering.
Wang’s engineering team collaborated with Irene Litvan’s laboratory in the Department of Neurosciences at the UC San Diego School of Medicine to develop the device. For several years, the two research groups have worked together on wearable sensors designed to monitor levodopa levels and help personalize treatment for people with Parkinson’s disease.
Sweat Provides Both the Power and the data for the Patch
The team positioned the sensor on the fingertip because it has a high density of sweat glands. The patch contains an absorbent gel that collects sweat from the skin in a sponge-like manner.
The gel is infused with concentrated salts and safe solvents. Since water naturally moves toward regions with greater salt concentrations, the mixture pulls sweat from the pores and channels it into the sensing system.
Enzymes built into the patch interact with levodopa in sweat, triggering a chemical reaction that generates a small electrical voltage. This voltage serves a dual purpose: it powers the sensor and provides the signal used to determine medication levels.
The voltage changes according to the amount of levodopa present. Lower readings indicate less of the drug, while stronger voltage signals correspond to higher levodopa concentrations.
Clinical Tests Matched Lab Measurements
The team evaluated the patch in healthy participants and people with Parkinson’s disease, finding that its levodopa readings closely matched those from conventional blood tests, which may take several days to return results.
The results also indicated that people with Parkinson’s metabolized and cleared levodopa from their bodies much faster than healthy participants. Researchers suggest that this difference may help explain the sudden return or worsening of symptoms as medication levels decline.
The technology could eventually support a closed-loop treatment system in which the patch continuously tracks levodopa levels and sends data to a pump that automatically administers the right dose when needed.
Read the original article on: SciTechDaily
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