UC San Diego fingertip sweat patch tracks Parkinson's levodopa without a battery

Engineers and neuroscientists at the University of California San Diego have built a soft, battery-free fingertip patch that continuously measures the Parkinson's drug levodopa in sweat, SciTechDaily reported, describing work published in Proceedings of the National Academy of Sciences. In clinical testing, the patch's readings were comparable to standard laboratory blood tests, which can take several days. Levodopa is the main treatment for Parkinson's motor symptoms, but the therapeutic window can shrink to about two hours as the disease progresses, and doctors often rely on incomplete patient diaries to retune doses. The sensor sits on the fingertip, where sweat glands are dense. An absorbent gel draws sweat into the patch; enzymes react with levodopa to produce a small voltage that both powers the device and reports drug level. Tests in healthy volunteers and people with Parkinson's also showed faster levodopa clearance in patients, which the team said may help explain sudden symptom return as levels fall. Co-first author Tamoghna Saha worked in Joseph Wang's engineering lab with Irene Litvan's neurosciences group. The paper's DOI is 10.1073/pnas.2610453123.