Researchers at the University of Michigan have developed a revolutionary at-home skin cancer detection device that could transform melanoma screening by eliminating the need for biopsies and doctor visits. The ExoPatch, a small silicone patch embedded with microscopic needles, has demonstrated success in distinguishing melanoma from healthy tissue in preclinical studies.
Breakthrough Microneedle Technology
The ExoPatch features star-shaped microneedles measuring just 0.6 mm long with tips less than 100 nanometers wide. "The star-shaped needles make puncture easier and less painful, but they are so small that they only go through the top-most layer of the skin, the epidermis, and do not draw blood," explained Sunitha Nagrath, professor of chemical engineering at the University of Michigan and co-senior author of the study published in Biosensors and Bioelectronics.
The microneedles are coated with a gel containing Annexin V, a protein that binds to exosomes from interstitial fluid between skin cells. Exosomes are nanosized particles (30-150 nanometers) released by cells that transport proteins, RNA and other molecules, serving as biomarkers for diseases including cancer.
Simple Testing Process
The testing procedure mirrors the simplicity of at-home COVID tests. When applied to skin for 15 minutes, the microneedles penetrate the epidermis without drawing blood. After removal, the patch is dissolved in an acidic solution to release captured exosomes. A test strip dipped into this solution displays two lines if melanoma exosomes are present or one line if absent.
"A fair-skinned person with moles must go to the doctor about every six months to send off a biopsy to see if they're malignant or benign," Nagrath said. "With this test, they could instead test at home, get the results right away and follow up with a dermatologist for a positive result."
Promising Preclinical Results
Initial testing on pig skin, chosen for its similarity to human skin, confirmed that microneedles penetrated between 350 and 600 nanometers within the epidermis. The device was then tested on mouse skin samples, half containing melanoma cells.
The results were striking: the ExoPatch collected 11.5 times more exosomal protein from melanoma samples compared to healthy tissue. Test strips produced lines 3.5 times darker for melanoma-positive samples, demonstrating clear differentiation between cancerous and non-cancerous tissue.
Broader Applications and Future Development
The research team envisions applications beyond melanoma detection. "This is the first patch designed to capture disease-specific exosomes from fluid under the skin. The potential applications are huge," Nagrath noted. By modifying the gel coating, the technology could potentially detect exosomes associated with lung, breast, colon, prostate and brain cancers.
The next phase involves conducting a pilot study in humans followed by clinical trials. The research, funded by the U.S. National Institutes of Health, has patent protection pending. If successful in human trials, the ExoPatch could revolutionize cancer screening by providing immediate, non-invasive testing capabilities for patients and healthcare providers.
