According to the World Health Organization, antibiotic resistance is one of the biggest threats to global health. Sensing and treating bacterial infections earlier could help improve patients’ recovery, as well curb the spread of antibiotic-resistant microbes. Now, researchers reporting in ACS Central Science have developed color-changing bandages that can sense drug-resistant and drug-sensitive bacteria in wounds and treat them accordingly.

A bandage changed color from green to yellow, and from green to red, in the presence of increasing concentrations of drug-sensitive (DS) and drug-resistant (DR) E.coli, respectively. (Credit: Adapted from ACS Central Science 2020, DOI: 10.1021/acscentsci.9b01104)

Xiaogang Qu and colleagues developed a material that changes color from green to yellow when it contacts the acidic microenvironment of a bacterial infection. In response, the material, which is incorporated into a bandage, releases an antibiotic that kills drug-sensitive bacteria. If drug-resistant bacteria are present, the bandage turns red in color through the action of an enzyme produced by the resistant microbes.

When this happens, the researchers can shine light on the bandage, causing the material to release reactive oxygen species that kill or weaken the bacteria, making them more susceptible to the antibiotic. The team showed that the bandage could speed the healing of wounds in mice that were infected with drug-sensitive or drug-resistant bacteria.

How It Works

According to the authors, “Sensing bacterial infections and monitoring drug resistance are very important for the selection of treatment options. However, the common methods of sensing resistance are limited by time-consuming, the requirement for professional personnel, and expensive instruments. Moreover, the abuse of antibiotics causes the accelerated process of bacterial resistance.”

In their paper, the authors construct a portable paper-based Band-Aid (PBA) that implements a selective antibacterial strategy after sensing of drug resistance. The colors of PBA indicate bacterial infection (yellow) and drug resistance (red), just like a bacterial resistance colorimetric card.

The paper notes that “on the basis of color, antibiotic-based chemotherapy and Zr-MOF PCN-224-based photodynamic therapy (PDT) are used on site to treat sensitive and resistant strains, respectively. Eventually, it takes 4 hr to sense, and the limit of detection is 104 CFU/mL for drug-resistant E. coli. Compared with traditional PDT-based antibacterial strategies, our design can alleviate off-target side effects, maximize therapeutic efficacy, and track the drug resistance in real time with the naked eye. This work develops a new way for the rational use of antibiotics. Given the low cost and easy operation of this point-of-care device, it can be developed for practical applications.”

The authors acknowledge funding from the National Natural Science Foundation of China and the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences.

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Medical Design Briefs Magazine

This article first appeared in the March, 2020 issue of Medical Design Briefs Magazine.

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