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How to Detect Wound Infections Without Removing Bandages? With Smart Wound Dressings and Built-in Healing Sensors

Researchers have developed scalable and cost-effective fluorescent nanosheets made from magnesium hydroxide that glow in response to changes in pH, simplifying the detection of potential wound infections under bandage dressings.

The market for global advanced wound dressing is currently valued at US$6.9 billion and is expected to increase to US$9.9 billion by 2028. This rapid projected increase is due to the rising prevalence of chronic wounds and conditions like diabetes and cancers that require frequent surgeries and post-surgical wound care.

“Currently the only way to check the progress of wounds is by removing bandage dressings, which is both painful and risky, giving pathogens the chance to attack,” said Dr. Vi Khanh Truong, a Vice-Chancellor’s Postdoctoral Fellow at Royal Melbourne Institute of Technology (RMIT).

Breaking away from traditional methods of wound care, researchers and engineers from RMIT University in Melbourne have developed a smart wound dressing from magnesium hydroxide with built-in pH-responsive fluorescent nanosensors. These glowing sensors can help patients and clinicians alike to monitor healing progress and look out for infections or compromised wound healing without having to frequently remove bandage dressings, thus keeping the wounds better protected.

Magnesium has long been known to be antimicrobial, anti-fungal, anti-inflammatory and highly biocompatible. However, there has been scarce research to validate its usage for dressings and bandages as most dressings rely on silver-based antimicrobials.

Taking this gap as an opportunity for innovation, the team experimented with magnesium and synthesised fluorescent magnesium hydroxide nanosheets. These nanosheets are reportedly 10,000 to 100,000 times thinner than human hair and are highly versatile. They can be contoured and fixed onto any biocompatible nanofibre, including standard cotton bandages.

Through laboratory investigations, these magnesium-based sheets were also found to be non-toxic to human cells and demonstrate powerful antimicrobial properties against some medically-relevant bacterial and fungal species, like the drug-resistant golden staph and Candida auris. Additionally, the nanosheets show strong potential to act as a pH probe to monitor the progress of wound healing.

During wound healing, the skin undergoes a process of acidification, since healthy skin is naturally acidic while infected wounds are usually fairly alkaline. Such changes in pH levels can be detected by the nanosheets. When exposed to UV light, they exhibit fluorescence signatures that vary in response to changes in pH. The nanosheets glow brightly in alkaline environments and fade in acidic conditions, thus allowing them to track the acidification process of wound healing.

In terms of production, project leader Dr. Truong noted that the development of fluorescent nanosheets is not only highly scalable for potential mass production, but also much more cost-effective than conventional silver-based dressings, which are estimated to be 20 times more expensive. Furthermore, it can retain its antimicrobial powers up to one week since first used, significantly longer than the usual antimicrobial wound dressings that begin to lose performance in a matter of days.

“With further research, we hope our multifunctional dressings could become part of a new generation of low-cost, magnesium-based technologies for advanced wound care,” commented Dr. Truong. [APBN]

Source: Truskewycz et al. (2021). Fluorescent Magnesium Hydroxide Nanosheet Bandages with Tailored Properties for Biocompatible Antimicrobial Wound Dressings and pH Monitoring. ACS Applied Materials & Interfaces.