Bacteria that can shrug off antibiotics is a medical problem that still needs answering, but this prototype could help reduce how much antibiotics are used on patients, and decrease the chances for bugs to become resistant. The experimental bandage from researchers at the University of Bath glows green when it comes into contact with unfriendly bacteria, (hypothetically) alerting medical staff when a wound is infected. A film formed by the body when defends against bacteria releases toxins that react with the bandage, puncturing the membrane of dye capsules stored in the bandage. That dye then glows (in case bright green didn't stand out enough) when it dissolves in the gel around it.