Microneedles embedded in a patch deliver cancer immunotherapy treatment directly to the site of melanoma, according to preliminary findings in animal studies.1

Immunotherapy is a promising new field of cancer treatment that has had positive results in patients with melanoma. It uses the body’s own immune system to fight off cancer. Anti-PD1 antibodies prevent the cancer cells from tricking the immune system and allow T cells to fight the cancer.

“However, this poses several challenges,” explained Chao Wang, PhD, a postdoctoral researcher in the joint biomedical engineering program at North Carolina State and University of North Carolina-Chapel Hill and co-lead author of a paper on the microneedle research. “First, the anti-PD-1 antibodies are usually injected into the bloodstream, so they cannot target the tumor site effectively. Second, the overdose of antibodies can cause side effects such as an autoimmune disorder.”

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This patch with microneedles was developed to address the need to deliver anti-PD1 antibodies locally to the skin tumor. The microneedles are composed of hyaluronic acid, which is biocompatible.

“This technique creates a steady, sustained release of antibodies directly into the tumor site; it is an efficient approach with enhanced retention of anti-PD-1 antibodies in the tumor microenvironment,” said Zhen Gu, PhD, an assistant professor in the biomedical engineering program and senior author of this study.

The technique’s efficacy against melanoma was tested in a mouse model. At 40 days, 40% of the microneedle-treated mice survived, compared with 0% survival in the untreated mice. When a combination treatment targeting both PD1 and CTLA4 was included in the microneedle patch, 70% of the mice survived and had no detectable melanoma after 40 days.

“Because of the sustained and localized release manner, mediated by microneedles, we are able to achieve desirable therapeutic effects with a relatively low dosage, which reduces the risk of auto-immune disorders,” said Gu.


1. Wang C, Ye Y, Hochu GM, et al. Enhanced cancer immunotherapy by microneedle patch-assisted delivery of anti-PD1 antibody [Letter]. Nano Lett. doi:10.1021/acs.nanolett.5b05030.