UC San Diego researchers reported a battery-free wearable patch that continuously monitors levodopa levels in Parkinson’s patients by sampling fingertip sweat. In a Proceedings of the National Academy of Sciences study, the device achieved performance comparable to standard laboratory tests while enabling real-time tracking. Led by neurologist Irene Litvan and bioengineer Joseph Wang’s team, the platform uses hydrogels and sensors positioned between styrene-ethylene-butylene-styrene sheets. The approach is designed to support tighter dosing adjustments than symptom diaries and faster feedback than waiting for lab tests. Clinically, the most immediate target is reducing dose timing gaps in advanced Parkinson’s, where the therapeutic window can narrow to hours and patients must avoid both under-dosing and over-dosing complications.