A team of scientists at Purdue University created a microneedle patch that can deliver oxygen and bactericidal agents to chronic wounds.
The bacterial biofilms that form over non-healing wounds, such as foot ulcers, are a formidable barrier to successful treatment. Such wounds are typically hypoxic and the bacteria within them are shielded from antibiotics within the biofilm structure. This latest technology is designed to non-invasively penetrate such biofilms to deliver calcium peroxide, resulting in bactericidal action and oxygen generation within the wound.
Chronic wounds are a significant source of suffering and disability worldwide. Certain patient populations, such as those with diabetes, are particularly prone to developing such wounds, and once established, they can be very difficult to treat. If treatment is unsuccessful or delayed, such wounds can progress, potentially leading to sepsis and/or limb amputation. The bacteria within such wounds can form a slimy biofilm layer that protects them from antimicrobial treatments, including those applied externally or systemically.
This microneedle technology is designed to penetrate the biofilm, delivering treatments directly into the infected wound. “The biofilm acts as a shield, hindering antibiotics from reaching infected cells and tissues,” said Rahim Rahimi, a researcher involved in the study. “When these microneedles pierce through the shield, they absorb the fluid underneath and dissolve, which delivers the antibiotic directly to the ulcerated cells and tissues.”
At present, clinicians typically debride such wounds to remove the biofilm layer. However, this can be very painful and can also damage healthy tissue. “The microneedles don’t cause pain because they are not long enough to touch nerve endings in the foot,” said Rahimi. “In this published study, the team assessed the microneedles on ex vivo porcine wound models. In fewer than five minutes, the microneedles dissolved, the antibiotic was delivered and the patch was removed.”
The patch contains an array of dissolvable needles that deliver calcium peroxide into the wound, resulting in an increase in tissue oxygenation levels. This makes the wound a more hostile environment for anaerobic bacteria, and also helps to improve tissue health, as poor blood flow is frequently a factor in wound development and progression.
So far, the researchers have tested the technology in porcine tissue samples, and found that the patch could kill bacteria responsible for wound biofilms, and also appears to produce very little cell death in human cells, suggesting that they are cytocompatible.
See a video about the technology below.
Study in ACS Applied Bio Materials: Flexible Microneedle Array Patch for Chronic Wound Oxygenation and Biofilm Eradication