Scientists showed that the antimicrobial peptide LL‑37 can be mixed into ultra‑thin fibers made from a polymer (PEO) using a process called electrospinning, and it still works to kill bacteria. The fibers slowly release the peptide, creating a small antibacterial zone in lab tests.

The aim of this study was to demonstrate targeted delivery of protein-based bactericidal antibiotics using electrospun polymer nanofibers. Previous studies have utilized electrospinning to create nanofibers for the localized delivery of therapeutic agents, including non-steroidal anti-inflammatory drugs (NSAIDs) and low molecular weight heparin. By employing established electrospinning techniques, nanofibers of varying diameters (100-500 nm) were generated from a 0.05 % solution of poly(ethylene-oxide) (PEO) and the antimicrobial peptide, LL-37 was incorporated into the nanofiber meshwork. Initial experiments determined that the strong electric fields caused by electrospinning do not disrupt the antimicrobial properties of LL-37, thus justifying the application of LL-37 as an electrospun component. Disk diffusion assays and especially bacterial filtration studies with E. coli were conducted to quantify the drug delivery potential of the nanofibers. Disk diffusion revealed a small zone of inhibition of about 1 mm around the LL-37-incorporated nanofiber disk. Filtration tests demonstrated that electrospun PEO fibers were capable of delivering LL-37 consistently while still maintaining their antimicrobial abilities.