The body prioritises healing wounds, which is why most wounds typically heal within 4 – 6 weeks. Wounds that take longer to heal are known as chronic wounds. Dressing such wounds can be challenging. For example, diabetic foot ulcers produce a significant amount of exudate, the fluid that oozes out of the wound, which requires frequent cleaning. This is important because the exudate can serve as a breeding ground for harmful bacteria.

To address the challenges of chronic wound healing, a research team led by Deepa Ghosh, Professor, Institute of Nano Science and Technology (INST) Mohali, Punjab, has developed an innovative, wearable, and self-powered dressing aid designed for patient’s use. This aid can effectively handle a significant amount of exudate, as well as facilitate wound healing and protect against bacterial infections.

Moist wound dressings such as hydrogels are increasingly being used for the treatment of chronic wounds as the moisture provided by these dressings boosts the effectiveness of enzymes like collagenase, that aids in the removal of dead cells and promotion of healing. However, a major drawback of traditional hydrogel dressings is its limited capacity to absorb excess fluids from the wound, resulting in the need for frequent hospital visits for the patient. The traditional wound dressing techniques generally focus solely on wound cleansing approaches, a measure that does not actively support wound healing. 

In order to address these gaps, the researchers developed a unique dressing aid consisting of two components: an electroactive powder made of hydrogel microparticles that can be applied directly to the wound, and an electroactive PVDF (polyvinylidene fluoride) membrane to cover the wound. 

A PVDF membrane was selected for its piezoelectric properties, allowing it to convert the mechanical energy produced during movement into electrical impulses. Research has indicated that applying mild electrical stimulation to wounds can have a positive effect on wound healing, including reduced inflammation and improved blood supply through new blood vessel formation. Ghosh says,

We collaborated with Dipankar Mandal, Professor at the Quantum Materials and Devices Unit at the INST to manufacture the PVDF membrane using electrospinning techniques. It involves the spinning of this membrane in a manner similar to that of a long textile.

The other component of this dressing is a powder comprising hydrogel microparticles. ​“We used plant-derived polymers to prepare the hydrogel powder containing silver nanoparticles, that crosslink to form a macrogel in presence of exudate” says Vineeta Panwar, Postdoctoral Fellow, INST Mohali, and the lead author of the study.

The silver nanoparticles (AgNP) in the powder serve two functions: first, they act as an antibacterial agent, and second, they serve as an electrical conducting agent that transfers electrical impulses to the wound.

Researchers conducted in vivo studies to assess the effectiveness of this dressing aid by creating wounds on lab animals and evaluating the wound healing process. Results showed that the wound size decreased significantly in the wounds treated with this dressing as compared to hydrogel control. Additionally, the electrostimulation from the hydrogel particles stimulated the growth of endothelial cells, potentially enhancing blood vessel formation and speeding up wound healing. The silver nanoparticles in the powder also exhibited antimicrobial properties against common bacteria such as Escherichia coli and Staphylococcus aureus.

Joey Shepherd, Senior Lecturer, University of Sheffield, UK, adds her comments on the potential implications of the study.

This multidisciplinary and in-depth study also throws up some interesting potential future prospects, including the use of the gel as a motion sensor and, perhaps, in the study of reversing hair loss.