Cold atmospheric plasma followed by in-situ electrospinning of arginine-loaded nanofibers promote infected diabetic wound healing.

Diabetic foot ulcers (DFUs) pose a major clinical burden due to chronic infection and impaired tissue regeneration. This study presents a dual-stage therapeutic strategy to promote the healing of infected diabetic wounds. In the first stage, cold atmospheric plasma was applied for 20 s which exerted a potent antibacterial effect against Staphylococcus aureus and Pseudomonas aeruginosa. The second stage involved in situ electrospinning of arginine-loaded mesoporous silica nanoparticles (Arg@MSN) embedded within polycaprolactone (PCL) nanofibers (Arg@NFs) using a portable, pen-like electrospinning device. MSN were spherical with an average diameter of 85 ± 10 nm and 80 % arginine loading was achieved. The nanofibers were randomly oriented with a fiber diameter ranging between 100 and 140 nm. Arg@NFs demonstrated 87 ± 5 % arginine release over seven days. In vivo studies showed that plasma-treated wounds exhibited a 2.85-fold increase in wound closure compared to the Arg@NFs group by day 14, while the combination therapy led to a complete wound healing. Histological and Masson's trichrome staining revealed full epithelialization and dense collagen deposition in the dual treatment group. Compared to monotherapies, the dual therapy group showed a significantly higher expression of VEGF, FGF, and PDGF and a significant downregulation of NF-κB and COX-2. These findings highlight that combining non-thermal plasma with arginine-releasing nanofibers is a promising therapeutic strategy for enhancing infected diabetic wound healing.