Conor Evans at Harvard oversaw the SMART bandage study.

International researchers have teamed up to create a liquid bandage that maps oxygen concentrations in skin wounds.

A lack of oxygen can lead to chronic sores. Current methods to assess wounds are either subjective or require highly specialized staff or equipment, says Harvard Medical School professor Conor Evans, Ph.D., the study’s lead author.

The bandage is made of phosphors – molecules that absorb light and then emit it via process known as phosphorescence. It’s painted onto the skin’s surface as a liquid, and dries to a solid thin film within a minute. A transparent barrier layer is then applied on top to protect the film and slow the rate of oxygen exchange.

A camera-based readout device provides a burst of light that triggers the emission of the phosphors inside the bandage, and then records the phosphors’ emission. The bandage glows blue-green when the tissue is oxygenated and red when there’s less oxygen. 

The work is part of the team’s program to develop a “Sensing, Monitoring and Release of Therapeutics” (SMART) bandage for improved care for acute and chronic wounds, says Evans, who is also a professor at the Wellman Center for Photomedicine in Massachusetts.

The goal is “to incorporate therapeutic release capabilities that allow for on-demand drug administration at a desired location,” he says. 

The study appears in Biomedical Optics Express.