Tag Archives: infectious diseases

Smart Wound Dressing

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.

New Type of Antibiotic to Fight MDROs

Since the advent of antibiotics, bacterial infections were no longer considered a death sentence. However, through overuse; microorganisms’ natural defense systems; and, medications’ unimodal mechanism of action, multiple drug-resistant organisms (MDROs) have emerged and are threatening human lives once again. Danish and Canadian scientists from the University of Copenhagen and the University of British Columbia, respectively, have engineered a synthetic peptide called host defense peptidomimetic 4 (HDM-4) that displays broad-spectrum antibacterial properties.

HDM-4 works by creating holes in the cell membrane of a bacterium and binds to the pathogen’s deoxyribonucleic acid (DNA) causing microbial death. HDM-4 also rapidly permeates bacterial cells and attaches to DNA in small lethal concentrations. The original peptide HDM-4 is modeled after is naturally found in animals and plants as part of the innate immune system—the first line of defense against pathogens before antibodies are formed. HDM-4 was found to enhance this immune response for superior pathogenocide.

When tested on bacteria-infested tissue, the synthetic peptide worked effectively against Gram-negative species and interfered with biofilm formation—a sugary bubble that bacteria build to protect themselves enabling them to reproduce and multiply. Due to the many ways HDM-4 goes about killing microbes, drug resistance is suspected to be low, thus hindering the progression of more potent bacteria while efficiently killing MDROs.

The scientists believe the creation of HDM-4 is an important component in developing a new type of antibiotic that prevents MDROs. However, there are barriers to furthering such research as pharmaceutical companies consider drugs for chronic diseases, such as diabetes and cardiovascular disorders, and cancer better long-term investments than the treatment of infectious diseases.

Medical conditions, such as sepsis or “blood poisoning,” can benefit from new medications that can quickly treat life-threatening diseases, albeit further research is required to discover any harmful side effects which require human trials. But, such findings are a crucial step in countering the ever-present war against infectious diseases. Hopefully, there will be champions to take up the cause.