Snail-collagen/chitosan nanocomposite film with silver nanoparticles for antimicrobial and regenerative wound healing

Infected wounds pose a significant clinical challenge, driving the need for advanced dressings that actively combat infection and promote healing. This study developed a novel bio-composite film by integrating silver nanoparticle-enhanced, metronidazole-loaded lipidic nanovesicles into a snail slime collagen-chitosan matrix. A Design of Experiment optimized lipidic nanovesicle formulation (loaded with metronidazole) (Lop) was fabricated and characterized (DLS, drug release). Silver nanoparticles (AgNPs) were incorporated to form optimized nanovesicle formulation incorporating Silver Nanoparticles (Lop-AgNPs), which were embedded into a snail slime collagen (SSC)-chitosan (CS) matrix to create the final Lop.M film (optimized bio-composite film (Lop-AgNPs in a Snail Slime Collagen-Chitosan matrix). The film was tested for physicochemical properties, antimicrobial activity (disc diffusion), and efficacy in a rat wound model. The optimized formulation (Lop) showed a vesicle size of 339.5 ± 3.1 nm, zeta potential of -58.2 ± 2.8 mV, and entrapment efficiency of 88.6 ± 4.5% w/w, with 45.9 ± 3.2% w/w cumulative metronidazole release after 4 h. Upon silver incorporation, vesicle size increased to 358.9 ± 5.7 nm and zeta potential to -62.1 ± 3.2 mV. The composite film (Lop.M) exhibited a swelling index (SI) of 18.2 ± 0.4% w/w, film thickness of 0.71 ± 0.05 mm, and folding endurance > 50 folds. Antimicrobial zones of inhibition reached 50 mm for P. aeruginosa and 45 mm for Escherichia coli. In vivo, Lop.M-treated wounds demonstrated 96.4 ± 2.3% closure by day 14 compared to 68.1 ± 3.8% in controls. The Lop.M film, which demonstrated 96.4% wound closure in 14 days and potent antimicrobial activity, presents a strategy for wound management that combines robust antimicrobial action with active promotion of tissue regeneration.