So, Toby Jenkins has made this incredible plaster that glows to signal infection. But how does this work?
All wounds get colonised by bacteria, often including pathogenic species, but small populations are generally not harmful, and the immune system can clear them. See Figure 1. In some cases, though, a population of harmful bacteria grows too big for the immune system to handle, and clinical intervention is needed to clear it. “We believe that this transition normally happens several hours, if not longer, before any clinical symptoms become evident,” says Jenkins. Earlier detection might give doctors time to head off the infection even before such symptoms arise.
Figure 1: Wound infection: all wounds contain bacteria, some get infected some do not
Jenkins states that the transition is “almost certainly” associated with the formation of a biofilm, a layer of microbes that work together and secrete a slimy substance to defend the colony against the immune system. At a high enough population density, the bacteria film switches on the production of toxins. The new dressing works because the outer layer of the dye-containing capsules is designed to copy aspects of a cell membrane. Toxins puncture the capsules like they would cells in the body, releasing the dye, which fluoresces when it is diluted by the surrounding gel.
Take a look at this video to see the bandage in action
CAUTION VIDEO CONTAINS A BRIEF GRAPHIC IMAGE OF SKIN BURNS THAT SOME VIEWERS MAY FIND DISTRESSING. NOT SUITABLE FOR YOUNGER VIEWERS.