The painless patch dissolves after delivering timed-release treatment.
Image credit: Purdue University/Chi Hwan Lee.
According to the American Cancer Society (ACS), roughly 100,350 new cases of melanoma will have been diagnosed in the U.S. by the end of 2020. Melanoma accounts for more fatalities than any other type of skin cancer, and the ACS anticipate 6,850 deaths from melanoma this year.
Recent advances in the delivery of topical chemotherapy for melanoma offer more effective postsurgical treatment options than standard chemotherapy, with reduced toxicity and side effects.
However, these therapies are conventionally microneedle-based and can be painful, limiting their acceptance.
Now, a new study from researchers at Purdue University, in Lafayette, IN, and published in the journal ACS Nano, proposes a solution.
The researchers have developed a patch that painlessly delivers a topical treatment for melanoma.
“We developed a novel wearable patch with fully miniaturized needles, enabling unobtrusive drug delivery through the skin for the management of skin cancers,” says Chi Hwan Lee, an assistant professor of biomedical engineering at Purdue and senior author of the study.
Removal by surgical excision is the preferred treatment for skin cancer. However, melanoma can be aggressive and recur frequently, often necessitating repeated rounds of conventionally delivered chemotherapy and radiation therapy.
Chemotherapy is a particularly important element of treatment when surgery is no longer an option or when the cancer has spread.
Because these therapies can be difficult for patients and often cause toxicity and other side effects, researchers are looking into topical chemotherapy as a more tolerable approach — one that may be equally effective, if not more so.
While topical chemotherapy shows promise, pain caused by the polymeric microneedles typically involved is holding back progress, say the study’s authors.
The microneedles used in topical chemotherapy are tiny but still big enough to cause pain. This is especially problematic, for example, in the treatment of ocular melanoma, melanoma of the eye, given the sensitivity of the cornea, the authors note.
The new patch is a flexible, thin, water-soluble film that quickly dissolves after deploying specially designed silicon nanoneedles into the skin. These nanoneedles are biocompatible — harmless to living tissue — and after they deliver timed-release medication, they are absorbed by the body.
Prof. Lee explains: “Uniquely, this patch is fully dissolvable by body fluids in a programmable manner, such that the patch substrate is dissolved within 1 minute after the introduction of needles into the skin, followed by gradual dissolution of the silicon needles inside the tissues within several months.”
The design of the researchers’ miniaturized nanoneedles makes them ideally suited as a vehicle for timed-release medication. As Prof. Lee notes:
“The uniqueness of our technology arises from the fact that we used extremely small but long-lasting silicon nanoneedles with sharpened, angular tips that are easy for their penetration into the skin in a painless and minimally invasive manner.”
These tiny, porous needles are designed with a large drug-loading capacity, ample for sustained delivery of medications before they eventually dissolve. Their capacity is comparable to the larger microneedles currently used for topical chemotherapy.
Prof. Lee recalls that he began looking for a better way to deliver topical chemotherapy after observing his daughter’s fear of needles during vaccination.
The research group that Prof. Lee runs at Purdue is focused on “bridging a critical gap between engineering and unmet clinical needs.” His team specializes in the development of wearable devices — what they term “peel-and-stick stickers” — for the delivery of drugs, and they also develop devices that monitor health conditions.
The melanoma patch was developed and tested by Prof. Lee’s lab, with the participation of Prof. Yoon Yeo, of Purdue’s College of Pharmacy, and Prof. Dong Rip Kim, of Hanyang University, in Seoul, South Korea.
