Bacterial resistance to antibiotics is rapidly developing, and it takes time to find out if a particular infection is resistant. Now, researchers at the Chinese Academy of Sciences have developed a smart bandage that changes color to indicate the presence of drug-resistant or drug-sensitive bacteria. It can then be triggered to release antibiotics or other chemicals to kill the pathogen.
When the bandage is attached to the wound, the color is green at first. If it detects bacteria that are still sensitive to antibiotics, it turns yellow in about four hours, and if drug-resistant bacteria are detected, it turns red.
This discoloration mechanism can be achieved by loading chemicals into bandages. Pathogenic bacteria often create more acidic environments for themselves, so the bandages contain a simple pH indicator that changes color if these pathogens are present. At the same time, the chemical nitric glycerin sense turns red when it senses an enzyme called beta-lactamase, which is produced by a group of drug-resistant bacteria.
This makes it easy for doctors and patients to see the wounds they are dealing with and respond as needed, saving on antibiotics that are not needed (which is actually why drug resistance is so common) and instructing when to use other methods.
The bandages themselves have some of these treatments built into them. The antibiotic ampicillin is loaded into a nanomaterial that dissolves under acidic conditions of bacterial infection, releasing drugs and killing them.
Of course, this is not effective for antibiotic-resistant bacteria, but for them, the bandage also hides a second attack. The bandage is also fitted with a material that is sensitive to light and releases reactive oxygen (ROS). It is well known that these molecules cause high levels of damage to microorganisms, causing direct damage or at least weakening them before antibiotics remove them.
The team tested the concept in mice infected with drug-sensitive or resistant E. coli. They found that the bandages changed color as scheduled and effectively killed both bacteria.
Although this is only proof of concept tested in mice at this stage, the researchers say that since the bandages themselves are mostly paper-based, they can be extended to clinical lymes relatively easily and cheaply. It also reduces the process that usually takes time to diagnose infections, determine whether they are resistant, and slows the spread of drug resistance.
The new study was published in the journal ACS Central Science.