Improvement of antibacterial and mechanical properties of chitosan matrix biodegradable polymer coating materials with green synthesized nanosilver obtained from aromatic arugula (Eruca vesicaria)

Abstract This study explores the development of antibacterial and mechanically enhanced nanocomposite films based on biodegradable chitosan (CS) and alginate (ALG) matrices. Initially, four polymer film formulations (CS1, CS2, CS-ALG, and ALG) were prepared and characterized to assess their baseline physical, mechanical, and antimicrobial properties. Among them, CS2 exhibited the highest tensile strength (31.68 MPa), while CS-ALG displayed the greatest elongation (19.68%), although their inherent antibacterial performance was limited. To enhance their functionality, silver nanoparticles (AgNPs) were synthesized through a green method using Eruca vesicaria (arugula) extract and incorporated into the CS2 matrix at different concentrations (1%, 2.5%, and 5%). The resulting CSNP films were comprehensively characterized by UV–Vis spectroscopy, SEM, FT-IR, EDX, and XRD, which confirmed the formation of well-dispersed, crystalline AgNPs with an average size of 16 nm. The CSNP3 sample (5% AgNPs) demonstrated significant improvement in both antibacterial activity (inhibition zones: 11–15 mm) and mechanical strength (54.6 MPa), while CSNP2 offered an optimal balance between flexibility and antibacterial efficacy. Overall, the results confirm that green synthesized AgNPs significantly improve the structural, mechanical, and biological performance of CS-based films. These eco-friendly nanocomposites have strong potential for biomedical applications, including antimicrobial wound dressings and sustainable surface coatings.