Skin Patch Detects Biomarkers in Interstitial Fluid Without Blood Draws

People with diabetes often need to check their blood glucose levels multiple times a day, a process that typically involves finger-pricking for blood samples or the insertion of a microfilament sensor under the skin. This daily routine is not only inconvenient and painful but also carries risks, as inserting a device into the body can trigger immune responses. The challenge of non-invasive biomarker detection also affects patients with other chronic conditions, such as traumatic brain injury, Parkinson’s disease, and cystic fibrosis, where diagnosis and treatment require continuous monitoring or targeted drug delivery. Now, researchers have developed a non-invasive patch that can detect disease biomarkers through the skin without the need for blood samples or implanted sensors.

The patch, created by a research team at Georgetown University (Washington, DC, USA), works by using an array of microheaters—each the size of a human hair—that briefly reach 100°C for a few milliseconds to create micropores in the outermost layer of the skin. These micropores allow interstitial fluid to naturally exude from the skin, providing a sample that contains the same biomarkers found in blood but without the complications of blood-based collection. Unlike other interstitial fluid monitors that require internal sensors, this patch is entirely non-invasive and pain-free, as confirmed by a pilot clinical trial.

The patch could potentially monitor biomarkers independently, allowing patients to change it only once a day, and thus offer a more convenient alternative for monitoring chronic conditions. The patch is also being developed for transdermal drug delivery. Unlike existing drug patches that require chemical modifications to penetrate intact skin, this patch utilizes the same micropores to deliver off-the-shelf drugs directly into the circulatory system, enabling scheduled dosing and reduced side effects. The technology has already been tested in early clinical trials, confirming its painless application and reliable fluid extraction.

The team is now exploring its potential to administer drugs like Levodopa for Parkinson’s disease, which currently loses efficacy when taken orally due to metabolism in the gastrointestinal tract and liver. By bypassing this pathway, the patch can significantly increase drug bioavailability while reducing required dosages and side effects. Additional research is ongoing to use the patch for diagnostic applications in cystic fibrosis, and a clinical trial involving patients is expected to begin soon. Ultimately, the researchers aim to launch a start-up to make the technology widely accessible and expand its use across a broad range of medical conditions.

“If there’s a marker in the blood that can be detected in the interstitial fluid, you can use the patch. If there’s a drug that can be used for the treatment of a condition, you can use the patch. There’s a whole host of conditions that can be treated,” said Makarand Paranjape, lead developer of the patch technology. "When you’re talking about drug delivery and even monitoring biomolecules for diabetes, it’s all about the quality of life. Can that be improved? This technology, I feel, will do that."

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