Smart dressing detects and treats bacterial infections independently

In recent years, more and more optimized and reactive dressings have been developed. From the nanofiber mesh dressing to ward off bacteria from a wound, via the anti-burn dressing preventing bacteria from multiplying, many devices are now used to fight infections. But recently, researchers have taken a new step: an intelligent dressing with variable colorization indicating the presence of an infection, its intensity, the presence of bacteria resistant or not to antibiotics and able to deliver the right type of antibiotic directly at the site of infection.

Scientists have developed a new type of smart dressing that can signal the type of bacterial infection in the bandaged wound, and then deliver the right therapeutic molecule. Researchers hope it could help fight antibiotic resistance, as well as heal wounds faster. The dressing is described in the journal ACS Central Science.

The dressing can take three colors with several variations: green means no bacteria or a low concentration of bacteria, yellow means drug-sensitive bacteria (DS) responding to standard antibiotics (and triggers the release of antibiotics), and red means resistant to antibiotics (DR), bacteria that need extra help to get rid of them. The more intense the color, the higher the concentration of bacteria.

The intelligent colorimetric dressing changes color depending on the type of bacteria detected: sensitive (DS) or resistant (DR) to antibiotics. Credits: ACS Central Science 2020

The delivery of treatment adapted to the type of infection detected

By testing the dressing on mice, the research team successfully treated both DS and DR E. coli infections using the new method. If drug resistance is detected, an intense beam of light can be used to activate the release of a highly reactive type of oxygen to weaken the bacteria, making them more sensitive to the antibiotics in the dressing.

Diagram explaining the operation of the dressing. When it detects an infection sensitive to antibiotics (pink bacteria), it delivers the right antibiotic, thus neutralizing the bacteria. And in the case of a resistant bacteria (purple bacteria), it delivers a light pulse activating an oxygenation reaction weakening the bacteria. Credits: Yuhuan Sun et al. 2020

Antibiotics are released as soon as the infection is detected, and because antibiotic resistance can also be detected, this means that additional treatments can be applied before the bacteria have a chance to mutate and defend themselves further.

“Detecting bacterial infections and monitoring drug resistance is very important for the selection of treatment options. However, common methods of detecting resistance are limited by time, there is need for professional personnel, and expensive instruments. In addition, the abuse of antibiotics causes the accelerated process of bacterial resistance,” write the researchers.

A rapid, informative therapeutic reaction without the need for nursing staff

The basic dressing can be easily transported and dispensed, and attacks bacteria immediately, with no special equipment or personnel required. Treatment does not have to wait for a doctor to make a diagnosis, and the dressing can get the right kind of medication applied as soon as possible.

In addition, the person wearing the dressing receives real-time information about what is going on with the infection, if there is one. Researchers say it offers many advantages over existing treatments that use light, including photodynamic therapy or PDT.

"Compared to traditional antibacterial strategies based on PDT, our design can mitigate off-target side effects, maximize therapeutic efficacy and monitor drug resistance in real time with the naked eye."


Colorimetric Band-aids for Point-of-Care Sensing and Treating Bacterial Infection

Yuhuan SunChuanqi Zhao Jingsheng NiuJinsong RenXiaogang Qu

ACS Cent. Sci. 2020,
Publication Date:January 29, 2020

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