Many clinically relevant immune cells, particularly resident memory T cells, are in barrier tissues such as the skin and are rarely found in routine blood samples. Until now, analyzing these cells has typically required invasive biopsies.
"Traditionally, studying some of the most important immune cells in the body requires a skin biopsy or blood draws. Because many of these cells live and respond in tissues like the skin, accessing them has meant invasive procedures," said Sasan Jalili, a biomedical engineer and immunologist at JAX. "We've shown we can capture them painlessly and noninvasively instead. This is especially important in sensitive or visible areas like the face or neck, where people often don't want biopsies because of scarring, as well as for older adults, frail patients, and very young children or infants."
The microneedle patch works by briefly reactivating resident memory T cells with a small amount of antigen. Once activated, these cells release signals that recruit additional antigen-specific T cells and inflammatory biomarkers to the skin. The patch absorbs immune cells and signaling proteins from interstitial fluid, enabling researchers and clinicians to assess immune response strength and specificity.
"In this study, we used antigen-specific T cells as a proof of concept, but the patch also captures other immune cells and inflammatory biomarkers," Jalili explained.
