Nanofiber-Based Wound Dressings Battles SSIs

A nanofiber-based wound dressings loaded with vitamin D can spur the production of antimicrobial peptides, according to a new study.

Researchers at the University of Nebraska Medical Center (UNMC; Omaha, USA), the University of California, San Diego (UCSD, USA), Oregon State University (OSU; Corvallis, USA), and other institutions used electrospinning to make poly(ϵ-caprolactone) wound dressings containing 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), the bioactive form of vitamin D. The dressings, which are capable of delivering vitamin D on a sustained basis over four weeks, can induce production of a peptide (hCAP18/LL37), which kills microbes by disrupting their membranes.

The dressings were tested on human skin in a culture dish, as well as in vitro with keratinocyte and monocyte cell lines, and in an in-vivo mouse model. The results showed that the 1,25(OH)2D3 loaded nanofibers significantly induced LL37 gene expression in monocytes and keratinocytes, skin wounds of humanized transgenic mice, and in artificial wounds of human skin explants. As the dressings work by enhancing innate immune responses rather than conventional antimicrobial compounds, they are less likely to contribute to drug resistance. The study was published on July 4, 2018, in NanoMedicine.

“Electrospinning is a versatile, simple, cost-effective and reproducible technique for generating long fibers with nanoscale diameters,” said professor of biochemistry and biophysics Adrian Gombart, PhD, of the OSU College of Science. “Electrospun nanofiber wound dressings offer significant advantages over hydrogels or sponges for local drug delivery. They provide several functional and structural advantages, including scar-free healing.”

LL-37 is a gene that encodes the only member of the human cathelicidin family, a group of antimicrobial polypeptides found in the lysosomes of macrophages, polymorphonuclear leukocytes (PMNs), and keratinocytes. Cathelicidins serve a critical role in mammalian innate immune defense against invasive bacterial infection. Vitamin D up-regulates genetic expression of cathelicidin, which exhibits broad-spectrum microbicidal activity against bacteria, fungi, and viruses.

Related Links:
University of Nebraska Medical Center
University of California, San Diego
Oregon State University