Sweat-Sensing Fingertip Patch Continuously Tracks Parkinson’s Medication Levels

Clinicians rely on levodopa to manage symptoms, yet dosing is difficult as therapeutic effects fluctuate and narrow over time. Current adjustments often depend on patient diaries and delayed laboratory testing, which can miss dangerous dosing gaps. To help address this challenge, engineers and neuroscientists have developed a wearable fingertip patch that continuously tracks medication levels using a patient’s sweat.

Developed at the University of California San Diego, the soft fingertip patch monitors levodopa, the gold-standard therapy for Parkinson’s disease. The device integrates a flexible printed circuit board with a fingertip patch that houses a sweat-collecting hydrogel, a levodopa sensor, and a paper fluidic channel. The engineering team at the UC San Diego Jacobs School of Engineering collaborated with the Department of Neurosciences at the UC San Diego School of Medicine.

The fingertip has a high density of sweat glands, enabling continuous sample collection. A specially engineered absorbent gel functions as a sweat sponge by using a highly concentrated mixture of salts and benign solvents to draw fluid from pores. When levodopa in sweat contacts enzymes embedded in the patch, a chemical reaction generates a measurable voltage that powers the device and reflects drug concentration, with lower voltage indicating low levels and higher voltage indicating high levels.

In clinical tests involving healthy volunteers and people with Parkinson’s disease, the patch tracked levodopa levels as accurately as standard laboratory blood tests that typically take days to return results. The data showed that individuals with Parkinson’s clear levodopa significantly faster than healthy individuals, which helps explain the abrupt return of symptoms observed in practice. These findings support real-time assessment of therapeutic windows during daily life.

Results were published in Proceedings of the National Academy of Sciences. The technology lays the groundwork for a closed-loop system in which a levodopa monitoring patch could communicate with a pump to deliver precise doses when needed. A complementary microneedle-based wearable approach to continuous levodopa monitoring was recently reported in ACS Sensors.

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