Gold Nanoparticles Loaded into Polymeric Hydrogel for Wound Healing in Rats: Effect of Nanoparticles' Shape and Surface Modification

Nanotechnology-based platforms have gained a growing interest in skin wound healing. Herein, gold nanoparticles (AuNPs) of different shapes (rods and spheres) and surface modifications (neutral, cationic and anionic charged polymers) were synthesized, characterized and loaded into a thermosensitive hydrogel (poloxamer 407). AuNPs-hydrogels exhibited excellent colloidal stability and demonstrated slow and prolonged release behavior over a 48-h of exposure using in vitro model. Hydrogels of poly ethylene glycol (PEG)-gold nanorods (AuNRs) and cationic poly allyl amine hydrochloride (PAH)-AuNRs demonstrated remarkable wound healing properties upon topical application on wounds using an animal model. PEGylated and cationic charged-AuNRs hydrogels have enhanced skin re-epithelization and collagen deposition after 14 days of daily wound treatment compared to controls, and they affected the gene expression of several inflammatory and anti-inflammatory mediators. Hydrogels of PEG-AuNRs and PAH-AuNRs exhibited potent in vitro antibacterial activity against staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). Furthermore, AuNPs of different shapes and surface modifications demonstrated low percentages of deposition into the main body organs after 21 days of daily wound treatment. Hydrogels of AuNRs could be a promising nano-platform for wound healing.