Centratherum anthelminticum Extract-Mediated Silver Nanoparticle-Loaded Biopolymeric Composite Films: Characterization and Evaluation of Their Antimicrobial Activity

This study reports a comparative evaluation of natural polymeric biomaterial films impregnated with silver nanoparticles (AgNPs) synthesized using the ethyl acetate (EA) extract of Centratherum anthelminticum (CA), yielding CA-EA extract-mediated AgNPs (CA-EA-AgNPs). The biopolymeric films were solution cast and confirmed for nanoparticle impregnation using techniques such as FTIR, XRD, and FESEM-EDAX. In addition to possessing antimicrobial activity, AgNPs also act as structural modifiers. AgNPs significantly enhanced tensile strength from 19.00 ± 0.62 MPa to 24.52 ± 0.97 MPa and Young’s modulus from 106.2 ± 18.2 MPa to 143.8 ± 7.15 MPa for chitosan (CH)-based films. For agar (AA)-based films, tensile strength increased modestly from 105.31 ± 1.18 MPa to 111.81 ± 1.78 MPa, maintaining a high Young’s modulus (1411.8 MPa). The water contact angle changed from 31.5° to 49.9° and from 56.9° to 86.7° for CH and AA films, respectively. The nanocomposite films demonstrated controlled equilibrium swelling kinetics without structural disintegration. The films exhibited moderately improved antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis, yielding zones of inhibition (diameter) from 7.67 ± 0.47 mm to 10.33 ± 0.47 mm, 7.33 ± 0.47 mm to 9.67 ± 0.47 mm, and 7.67 ± 0.47 mm to 8.67 ± 0.47 mm for chitosan-based films and from 7.67 ± 0.47 mm to 11.67 ± 0.47 mm, 7.67 ± 0.47 mm to 10.67 ± 0.47 mm, and 7.33 ± 0.47 mm to 8.67 ± 0.47 mm for agar-based films, respectively, against their respective controls. The above findings demonstrate the potential of these nanoparticle-loaded biopolymer films as potent antimicrobial biomaterials for prospective wound management applications.