Wound Healing in Wistar Rat Potential Treatment Using Magnetic Nanoparticles Coated with Bioplastic Produced from Desmonostoc muscorum

Abstract Chronic wound management remains a significant clinical challenge due to persistent infections and delayed tissue regeneration. In this study, the development and the evaluation of polyhydroxyalkanoate-coated magnetic nanoparticles (PHA-MNPs) derived from the cyanobacterium Desmonostoc muscorum as a novel topical agent for wound healing. PHA was extracted from D. muscorum biomass at a yield of 0.56 ± 0.03 g per g dry cell weight and used to coat magnetite nanoparticles synthesized via co-precipitation. The resulting PHA-MNPs were characterized by TEM (mean diameter 18 ± 3 nm), DLS (zeta potential − 25 ± 2 mV), FTIR, GC-MS, and UV–Vis spectroscopy. Antimicrobial activity against Escherichia coli , Staphylococcus aureus , and Pseudomonas aeruginosa was quantified by broth microdilution assays (MICs comparable to ampicillin). Antibiofilm efficacy was assessed in microtiter plate assays, and hemocompatibility by hemolysis testing (< 5% hemolysis at ≤ 200 µg/mL). Cytotoxicity toward human epidermoid carcinoma (A431) and skin fibroblast (HFB4) cells was determined by MTT assays. In vivo wound healing was evaluated in a Wistar rat excisional wound model. Animals received topical low-dose PHA-MNPs (50 mg/kg), high-dose PHA-MNPs (100 mg/kg), Iruxol ® (positive control), or no treatment for 16 days. Wound closure was measured photographically, and tissue samples underwent histopathological analysis. PHA-MNPs exhibited potent antibacterial and antibiofilm activities, selective cytotoxicity (IC₅₀ 45 µg/mL for A431 vs. >200 µg/mL for HFB4), and excellent hemocompatibility. Low-dose PHA-MNP treatment achieved 85 ± 5% wound closure, comparable to Iruxol ® (95 ± 3%) and superior to the high-dose group (60 ± 6%) and untreated controls. Histology confirmed complete epithelialization and robust collagen deposition in low-dose and Iruxol ® groups. PHA-MNPs produced from D. muscorum combine antimicrobial, antibiofilm, and regenerative properties with biocompatibility, representing a promising, sustainable nanobiomaterial for advanced wound care applications.