Chronic wounds, such as diabetic foot ulcers, can be painful and debilitating to treat because antibiotic-resistant “biofilms” grow on the damaged tissue. However, it has been demonstrated that a novel form of microneedle patch can deliver medication through such coatings.
Bacterial biofilms consist of colonies that cling to one another via a slimy polymer matrix. However, antibiotics and other medications applied topically have trouble entering that matrix, preventing them from reaching the damaged tissue underneath. Thus, before treating the wounds, doctors often peel off biofilms. This is uncomfortable for the patient, and usually, healthy tissue with the biofilm comes off, which puts the healing process on hold.
To confront these issues, scientists at the University of Purdue, Indiana, have developed a biodegradable polymer composite patch with a set of tiny medication-laden “microneedle” studs on the bottom.
These microneedles penetrate the biofilm and absorb the fluid of the underlying tissue when the patch is placed to a chronic wound. This way, the medication can dissolve into the tissue safely. As the needles aren’t long enough to reach nerve endings, the patient feels no pain while this takes place. The patch is removed after the treatment is over, leaving the biofilm and the rest of the wound – untouched.
During lab tests, the microneedle patch successfully delivered calcium peroxide through biofilms and into the underlying tissue on pig skin samples with chronic wounds. In addition, the needles dissolved in less than five minutes. Calcium peroxide produces oxygen, which kills bacteria and stimulates tissue growth.
Human clinical trials are currently being planned.
An article describing the research, led by Assoc. Prof. Rahim Rahimi, was recently published in ACS Applied Bio Materials.