Developing chitosan nanocomposite with silver nanoparticle, sesame oil, and Verbena officinalis extract for wound dressing: in vivo and in vitro evaluation

This study develops two types of chitosan-based composite sponge containing silver nanoparticles and either verbena officinalis extract or sesame oil. An optimal solution of silver nanoparticles and chitosan was obtained from the antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. The Verbena officinalis extract was produced and analyzed using HPLC to verify the chemical composition of the solution. The chitosan/silver nanoparticle/verbena officinalis extract (CS/AgNP/V) and chitosan/silver nanoparticle/sesame oil (CS/AgNPs/S) composites were synthesized and analyzed through the Fourier-transform infrared spectroscopy (FTIR). Morphological analyses (FESEM) confirmed composite formation, with CS/AgNPs/V exhibiting larger pores (mean 74.98 ± 31.04 μm) and higher porosity (68%) than CS/AgNPs/S (53.78 ± 18.32 μm; 43%). Furthermore, the Energy Dispersive X-Ray Spectroscopy (EDX) images depicted the presence of nanoparticles in the composites. Accordingly, CS/AgNPs/V manifested superior water absorption (ES = 15.51) and complete in vitro biodegradability (100%), whereas CS/AgNPs/S was degraded by 45.8%. Antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa revealed eight and six log reductions for CS/AgNPs/V as opposed to three and four log reductions for CS/AgNPs/S. Moreover, in vivo assays demonstrated significantly faster wound closure with CS/AgNPs/V (p < 0.01 on day 17) and nearly full regeneration by day 21. In addition, collagen density reached ∼91% for CS/AgNPs/V versus ∼82% for CS/AgNPs/S and ∼75% for the control. Overall, the CS/AgNPs/V nanocomposite was characterized by enhanced biodegradability, antimicrobial efficacy, and tissue regeneration, indicating strong potential as a bioactive wound dressing substance.