Surgical Dressing Helps Kill Melanoma, Regenerate Healthy Cells

Scientists at the University of Nottingham in the UK have created a surgical dressing that is specifically designed to facilitate and enhance photothermal therapy following melanoma resection. The dressing allows for near-infrared photothermal therapy that lasts just 15 seconds every 48 hours. The concept involves killing any remaining melanoma cells, while encouraging healthy cells to regenerate within the resection site. The dressing contains graphene oxide (a photothermal agent, which converts the energy from light to heat, killing cancer cells), elastin, and ethanol. Combining the graphene oxide with elastin reduces its cytotoxicity, meaning that it does not pose a threat to healthy cells, but still enables photothermal therapy to kill residual melanoma cells. The ethanol acts to help chemically reduce the graphene oxide, making photothermal therapy more efficient, and also forms an antiseptic component within the dressing. Melanoma is a highly aggressive cancer, and once detected, surgical resection is the most common option. However, surgeons frequently err on the side of caution and remove a large portion of tissue to ensure that they have excised all the cancer and help to prevent recurrence. Another option is to use photothermal therapy, where the resection site is exposed to light and a photothermal agent converts the energy from the light to heat, helping to kill residual cells. If performed effectively, this approach could potentially allow surgeons to be more conservative in their resection. “Given the aggressive nature of melanoma, surgical resections to remove it have to be significantly larger than the size of the tumors to minimize the presence of residual cells,” said Yuanhao Wu, a researcher involved in the study. “This creates a new wound and delays healing. Beyond the prevention of tumor recurrence and promotion of tissue healing, our dressings could also lead to smaller surgical resections and practical post-surgery treatments that are non-invasive and could be delivered at home.” It can be difficult to deliver photothermal agents to tumors through the bloodstream, as they can have an erratic blood supply and tortuous vasculature, and some photothermal agents can have negative effects on healthy cells. This latest technology aims to place the photothermal agent, in this case reduced graphene oxide, directly onto the resection site. So far, the researchers have shown that the dressings only require 15 seconds of irradiation with near-infrared light every 48 hours to produce effective photothermal therapy. Patients could even administer the light therapy by themselves at home. “We know that graphene oxide (GO)-protein materials offer huge potential for biomedical devices but the need for harsh processes to make graphene oxide conductive at high temperatures has limited their use,” said Alvaro Mata, another researcher involved in the study. “Our new method offers a solution to this, enabling the fabrication of protein-based materials with both efficient photothermal conductivity and bioactive properties. These materials could be used as dressings for post-surgery treatment and healing of skin cancer, operating within a narrow temperature window where “bad” cells are killed and “good” cells are not.”