Self-Powered Microneedle Patch Enables Painless Biomarker Monitoring Without Blood Draws
Key Insights
Researchers at North Carolina State University and University of North Carolina at Chapel Hill developed a self-powered microneedle patch that collects dermal interstitial fluid for biomarker analysis without requiring blood draws or external power sources.
The patch successfully collected measurable biomarker samples in as little as 15 minutes and stored them for at least 24 hours in proof-of-concept testing using synthetic skin models.
The technology targets cortisol monitoring initially but could expand to track glucose, lactate (search), and inflammation markers, offering a more comfortable and cost-effective alternative to traditional blood testing.
Researchers have developed a breakthrough self-powered microneedle patch that can monitor health biomarkers without drawing blood, offering a painless alternative to traditional blood testing methods. The innovation, published in Lab on a Chip, represents a significant advancement in wearable health monitoring technology.
The patch, developed by teams at North Carolina State University and the University of North Carolina at Chapel Hill, collects dermal interstitial fluid (ISF) from just beneath the skin's surface. "ISF contains almost all of the same biomarkers found in blood," explains Dr. Michael Daniele, the study's corresponding author. "What's more, ISF makes for a 'cleaner' sample. It streamlines the biomarker testing process."
Revolutionary Four-Layer Design
The microneedle patch consists of four distinct layers working in harmony. The outermost polymer housing protects the internal components, while a glycerol-loaded gel layer creates osmotic pressure. A paper layer stores the collected fluid samples, and at the base, tiny microneedles made from swelling materials penetrate the skin painlessly.
When applied to skin, the microneedles swell upon contact with ISF and begin drawing fluid upward through capillary action. The glycerol in the gel layer generates osmotic pressure that pulls additional ISF through the paper until it reaches saturation. "The paper is where the ISF is stored," Daniele notes. "When you take the patch off, you remove the paper strip and analyze the sample."
Promising Early Results
In proof-of-concept testing using synthetic skin models, the patch demonstrated impressive performance. The device collected measurable biomarker samples in as little as 15 minutes and successfully stored them for at least 24 hours. The researchers focused their initial testing on cortisol, a stress-related hormone that fluctuates throughout the day.
"Cortisol is something people may want to monitor multiple times a day without drawing blood repeatedly," Daniele explains. The continuous monitoring capability addresses a significant limitation of traditional blood tests, which provide only snapshot measurements and require repeated uncomfortable procedures.
Cost-Effective Alternative
The patch offers potential economic advantages over conventional blood testing methods. Traditional blood draws require trained personnel, syringes, vials, and laboratory processing. "Drawing blood requires vials, needles, and usually a phlebotomist. The patch doesn't require any of those things," Daniele states.
The materials used in the patch are common and inexpensive, with microneedles representing the highest cost component. "The highest cost of the patches would be manufacturing the microneedles, but we think the price would be competitive with the costs associated with blood testing," Daniele adds.
Expanding Applications
While the initial focus centers on cortisol monitoring, the technology's potential extends far beyond stress tracking. Since ISF shares most biomarkers found in blood, future applications could include monitoring glucose levels for diabetes (search) management, lactate (search) for athletic performance, or inflammatory markers for disease detection.
The research team has already begun human testing and is developing companion devices to interpret the collected data. "We've already developed an electronic device that can 'read' cortisol levels from the paper strip and are working on another device for a different biomarker," Daniele reports.
Clinical and Commercial Prospects
The patch's passive operation eliminates the need for batteries or external power sources, making it suitable for continuous monitoring in various settings. The technology could particularly benefit patients requiring frequent monitoring, individuals with needle phobias, and healthcare systems seeking cost-effective diagnostic solutions.
The research team is actively seeking industry partnerships to advance the technology toward commercialization. "We'd love to talk with companies in the diagnostic space to explore additional applications, and we'd also like to talk with potential partners about scaling up production," Daniele states.
The development was supported by NSF's ASSIST center, the NC State Institute for Connected Sensor-Systems, the Chancellor's Innovation Fund, and SEMI-NBMC grants. Daniele also serves as an officer and founder of DermiSense, Inc. (search), which focuses on commercializing microneedle-based technologies.