Antibiotic resistance in bacteria may rise due to increased usage of hand sanitizers and antibacterial-containing soaps brought on by Covid-19. Identifying an antibiotic-resistant strain of bacteria is necessary before it can be effectively treated, but this requires additional testing that can be lengthy and costly. Scientists at the University of Science and Technology in China got around this by designing smart band-aids that change color upon contact with antibiotic-resistant bacteria. 

The scientists integrated a chemical structure called a metal organic framework (MOF) onto their band-aid and loaded it with various color chemicals. The pH of your skin decreases during a bacterial infection, and they included a chemical called bromophenol blue, that turns from blue to yellow in more acidic environments. 

To detect antibiotic resistant bacteria, the scientists took advantage of an enzyme they produce called β-lactamase. This enzyme breaks down common antibiotics like penicillin. It also breaks down the second chemical loaded into the bandage, called nitrocefin. When that happens, the color of the nitrocefin changes from yellow to red. So, the band-aids that these scientists designed turn red when they are covering a wound with an antibiotic-resistant bacterial infection, yellow if atop normal, antibiotic-sensitive bacteria, and stay colorless on infection-free wounds.

To treat the infection, the scientists took advantage of non-antibiotic therapies such as UV radiation and reactive oxygen species. UV light causes DNA damage in bacterial cells. Because of the design of the bandage's metal-organic framework, UV light shined on the band-aid also creates special oxygen molecules called reactive oxygen species (you may have heard of these as justification for eating antioxidant-rich foods). These reactive oxygen species poke holes in bacterial membranes. 

The researchers demonstrated the effectiveness of the band-aids by applying them to E.coli-infected wounds on mice. In just a few days, the band-aids turned yellow or red (in case of drug-resistant E. coli), UV radiation killed the infection, and the wound healed. As the relative cost of making these smart band-aids is low, large-scale production and clinical application of this exciting innovation could be implemented quickly.