Microneedle Skin Patch Enables Noninvasive Immune Monitoring

Immune monitoring is useful to monitor processes like vaccination and during diseases like infectious disease, cancer, and autoimmunity. However, detection of antigen-specific lymphocytes is challenging given that are low in frequency and have a dispersed distribution.

Now, the first bandage-like, painless, microneedle patch that can sample the body’s immune responses from the skin has been developed. The device detects inflammatory signals within minutes and collects specialized immune cells within hours without the need for blood draws or surgical biopsies.

The study appears in Nature Biomedical Engineering in the paper, “Leveraging tissue-resident memory T cells for non-invasive immune monitoring via microneedle skin patches.”

The patch is helping researchers and clinicians study immune responses in aging and skin autoimmunity, including vitiligo and psoriasis. In the future, it could make it easier to track how people respond to vaccines, infections, and cancer therapies by complementing traditional blood tests and biopsies while being far easier on patients.

“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, PhD, an assistant professor at The Jackson Laboratory (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.”

Initially developed during Jalili’s postdoctoral training at MIT, the platform was further advanced from mouse models toward clinical application at JAX through collaborations with the University of Massachusetts Chan Medical School.

The patch absorbs immune cells and signaling proteins from the skin after resident memory T cells are briefly reactivated with a small amount of antigen. It contains hundreds of microscopic needles made of an FDA-approved polymer. A seaweed-derived hydrogel coats the needles and absorbs immune cells and molecules from skin interstitial fluid. The microneedles reach only the upper skin layers, causing minimal irritation and no damage to nerves or blood vessels.

In the study, tissue-resident memory T cells, the authors write, were “first induced by antigen sensitization and subsequently restimulated by intradermal inoculation of the same antigen to trigger the ‘alarm’ and immune recruitment functions of these cells, leading to accumulation of antigen-specific T cells from the circulation over several days.”

“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,” said Jalili. In mouse vaccination models, the patch dramatically boosted the recovery of antigen-specific T cells, recruiting many of these cells from the bloodstream rather than skin. In a human participant with allergic contact dermatitis at UMass Chan, the patch also collected a rich mix of immune cells and signaling proteins, including resident memory T cells.

“This study marks the first demonstration of live human immune cell sampling using a microneedle patch,” Jalili said. “This opens the door to a new way of monitoring immune responses that’s practical, painless, and clinically feasible.”

The patch may be especially useful for skin conditions, since immune cells that drive conditions such as allergic dermatitis, psoriasis, and vitiligo already live in the tissue. Jalili is already using it to study how age-related skin changes contribute to chronic inflammation and frailty in older adults.

Looking ahead, the patch could eventually support at-home monitoring, allowing patients with skin conditions to track unpredictable flare-ups. The technology could also be adapted for oral or nasal cavities, opening the door to monitoring mucosal immune responses.

“People wouldn’t need hours of sampling. Even 15 to 30 minutes can be enough to detect inflammatory signals and get a sense of what’s happening in the tissue,” Jalili said.