Smart Wound Dressing Emits Light When Dressing Needs to Come Off
The human skin provides a natural barrier to pathogens and serves as the first line of defense against harmful microbes. When the skin’s integrity is broken via cuts, sores, or other wounds, the site of broken skin potentially becomes an entryway for a systemic infection. Hence, good wound care is crucial from developing sepsis, or widespread infection that can lead to multi-organ failure, particularly in people with chronic diseases, e.g. diabetes, rheumatoid arthritis, or those who are immunocompromised, e.g. receiving chemotherapy, immunotherapy, battling active HIV infection.
Good wound care technique is largely dependent on the specific characteristics of the wound: nature of wound, size, amount of exudate, illness that can exacerbate wound, etc. However, one thing clinicians agree on is that the wound should be kept covered until a temporary barrier, like a scab, forms to prevent infection. Checking on status of wound healing may require frequent dressing changes, which can be detrimental to proper healing. As a result, Swiss scientists collectively from University Hospital Zurich, Centre Suisse d’Electronique et de Microtechnique (CSEM), EMPA, and ETH Zurich developed a type of smart wound dressing called Flusitex—short for fluorescence sensing integrated into medical textiles.
Flusitex works by monitoring the pH (acidity or alkalinity) of the wound. When normal healing is progressing well, pH jumps to 8 before resting around 5 or 6. If the wound’s healing trajectory deviates from standard healing protocols, or the wound becomes chronic, pH may oscillate between 7 and 8. Integrated into the smart wound dressing are pyranine and benzalkonium chloride molecules. Pyranine is a pH-sensitive fluorescent dye, which enable the dressing to fluoresce when a UV light is shined on the bandage at an internal pH of 7.5—an indication the chronic wound is on the verge of healing—which alerts clinicians to leave the dressing alone. Benzalkonium chloride, an antiseptic, is particularly known for killing Staphylococus aureas bacteria, which are commensal on the human skin and may cause opportunistic infections if allowed to enter the wound bed.
To make Flusitex more accessible and user-friendly, scientists are exploring ways to allow an app and camera from a smartphone to interpret fluorescing pH changes on the smart wound dressing so that users can monitor wound healing progress from home.