Colorimetric Bandages Identify and Treat Bacterial Infections

Innovative color-changing bandages can sense drug-resistant and drug-sensitive bacteria in wounds and treat them accordingly, claims a new study.

Developed at the Chinese Academy of Sciences (CAS; Shenyang, China) and the University of Science and Technology of China (USTC; Hefei, China), the new paper-based bandaid (PBB) visually implements a selective antibacterial strategy. The PBB changes color from green to yellow when it contacts the acidic microenvironment of a bacterial infection; if drug-resistant bacteria are present, the bandage turns red in color through the action of an enzyme produced by the resistant microbes.


If an infection is detected, the PBB releases an antibiotic that kills drug-sensitive bacteria. When drug resistant bacteria are detected, Zr-MOF PCN-224-based photodynamic therapy (PDT) is used on the wound site to treat the resistant strains by releasing reactive oxygen species (ROS) that kill or weaken the bacteria, making them more susceptible to the antibiotic. The limit of detection is 104 CFU/mL for drug-resistant E. coli. The study was published on January 29, 2020, in ACS Central Science.

“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,” concluded senior author Xiaogang Qu, PhD, of the CAS Changchun Institute of Applied Chemistry, and colleagues. “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.”

PDT is used clinically to treat a wide range of medical conditions, including wet age-related macular degeneration and malignant cancers, and is recognized as a treatment strategy which is both minimally invasive and minimally toxic. While the applicability and potential of PDT has been known for over a hundred years, the development of modern PDT has been a gradual one, involving scientific progress in the fields of photobiology and cancer biology, as well as the development of modern photonic devices, such as lasers and light emitting diodes (LEDs).

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