Heat-activated patch shows promise for noninvasive melanoma treatment

Melanoma is a deadly form of skin cancer that is typically removed surgically. Now, researchers publishing in ACS Nano report they have developed a potential noninvasive treatment for melanoma in the form of a stretchy, heat-activated patch similar to a bandage. When activated, the patch releases copper ions that kill the underlying cancer cells and prevent them from spreading. In tests with mice, the researchers say the patch reduced melanoma lesions without damaging surrounding tissue. 

Melanomas typically form in the outermost and middle layers of the skin. That makes it challenging to kill cancer cells while leaving the surrounding healthy tissue unscathed. Recent advancements in nanotechnology could result in a gentler, more targeted option for skin cancer therapy. One example is laser-induced graphene (a laser-etched porous carbon material). Researchers Xin Li, Shi Chen, Meijia Gu and Ruquan Ye took this material and filled the pores with copper(II) oxide and embedded it in a stretchy silicone polymer to create a skin patch for targeted melanoma therapy. 

On its own, the patch is soft, stretchy, breathable on the skin, and chemically inert. But the researchers hypothesized that by gently heating the patch, it would release copper ions that interact with cancer cells' DNA and kill them through oxidative stress. This pathway should also trigger an immune response that would inhibit tumor cell migration into other parts of the body (metastasis). 

To test the concept, the researchers placed the patch over melanoma cells cultured in the laboratory. They warmed the patch to 108 degrees Fahrenheit (42 degrees Celsius) with a low-power laser. In its now-activated state, the patch released copper ions into the melanoma cells directly beneath it. The team found that the copper ions killed most of the cultured melanoma cells and slowed cell movement. 

In a preliminary 10-day animal study, they placed patches on mice with melanoma. On days 1 and 5, the patches were activated with a laser for one hour. The treatment reduced melanoma lesions by 97%. As predicted, tissue samples showed that cancer cells had not migrated beyond the tumor borders, and copper ions had not accumulated in the organs or blood. 

These early study results, combined with the patch's reusability and ease of administration, led the research team to conclude that the technology could someday be used for targeted, safe and efficient melanoma treatment in humans.