Scar-reducing ionically conductive chitosan bandage: Combining ionic and electrical stimulation for optimal wound healing.

Abstract

Large, complex wounds frequently exhibit suboptimal healing, leading to scarring and functional impairment. While bioactive materials and electrical stimulation (ES) show promise, their individual limitations call for novel approaches. This study investigates the combined effects of combining 4-aminopyridine (4AP) and electrical stimulation (ES) on human dermal fibroblasts (hDFBs) using a stable, ionically conductive (IC) chitosan-based scaffold for controlled drug delivery. To enable sustained release of the highly water-soluble 4AP, halloysite nanotubes (HNT) were incorporated as secondary carriers within the bandage system. In vitro assays revealed that combining 4AP (100 ng/mL) with ES significantly enhanced hDFB metabolic activity, wound closure, and maintained mitochondrial function along with reduced inflammation under stress condition. Gene expression analysis showed upregulation of key extracellular matrix (ECM) and growth factor genes at day 7, followed by a shift to the remodeling phase by day 14 in vitro. Histological and immunohistochemical analyses revealed improved ECM organization, as indicated by an optimal collagen I/III ratio; enhanced angiogenesis (CD31); increased cellular activity (α-SMA, vimentin, Ki-67); and elevated expression of neurotrophic factors in the combined full-thickness wound treatment group. These findings highlight a potential additive mechanism, in which 4AP may enhance the effects of ES by supporting cellular metabolism. This integrated approach offers a promising, multifaceted strategy for improving dermal wound healing and minimizing scarring, warranting further in vivo investigation for clinical translation.