Developing chitosan nanocomposite with silver nanoparticle, sesame oil, and <i>Verbena officinalis</i> 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 <i>verbena officinalis</i> extract or sesame oil. An optimal solution of silver nanoparticles and chitosan was obtained from the antibacterial activity against <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i>. The <i>Verbena officinalis</i> extract was produced and analyzed using HPLC to verify the chemical composition of the solution. The chitosan/silver nanoparticle/<i>verbena officinalis</i> 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 (E_S = 15.51) and complete <i>in vitro</i> biodegradability (100%), whereas CS/AgNPs/S was degraded by 45.8%. Antibacterial activity against <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i> revealed eight and six log reductions for CS/AgNPs/V as opposed to three and four log reductions for CS/AgNPs/S. Moreover, <i>in vivo</i> assays demonstrated significantly faster wound closure with CS/AgNPs/V (<i>p</i> < 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.