Fabrication and In Vitro Evaluation of LL37-Loaded Electrospun PHB/Collagen Nanofibers for Wound Healing

Abstract

Skin repair is essential in the treatment of burns and wounds. After an injury, the concept of tissue engineering emerges to restore skin function and facilitate wound healing. This field often involves the use of biodegradable and biocompatible materials as a primary scaffold for tissue regeneration. In this study, a PHB/Collagen wound dressing mat loaded with the antimicrobial peptide LL37 was developed via electrospinning. The polymer solutions were prepared by dissolving polyhydroxybutyrate (PHB) biopolymer extracted from Cereibacter sphaeroides, commercial PHB, and marine collagen in hexafluoroisopropanol (HFIP). The resulting nanofibers were characterized using Field-Emission Scanning Electron Microscopy (FE-SEM), Thermogravimetric Analysis (TGA), X-Ray Diffractometry (XRD), and an Optical Tensiometer. Antibacterial activity assessments were conducted against Staphylococcus aureus (ATCC 29213) and Escherichia coli (ATCC 25922). Degradability studies were carried out in DMEM medium, cytotoxicity tests were performed on the L929 fibroblast cell line, and the wound healing effect was investigated on the HS2 keratinocyte cell line. To evaluate the properties of the designed material under in vitro conditions, the morphology of cells on the nanofiber was examined using an inverted light microscope. The findings demonstrated that the nanofibers were biocompatible in vitro and exhibited no toxic effects. And, compared to the control groups, the 5.56 nmol LL37-loaded PHB/Collagen nanofibers significantly enhanced wound closure by 15–30% and effectively reduced the viability of S. aureus and E. coli by 20–25% and approximately 80–85%, respectively. These results highlight the therapeutic potential of LL37-loaded PHB/Collagen nanofibers for use in wound healing applications.