Green synthesis of Ag/VO and Ag/VO-curdlan nanocomposites from Sargassum latifolium extract for enhanced antimicrobial and antioxidant activities.

The emergence of clinic-isolated bacteria and their ability to develop resistance mechanisms against conventional antimicrobials highlights the urgent need for novel, sustainable antimicrobial agents. This study explores the synthesis of Ag/VO nanocomposites (NCs) using Sargassum latifolium extract, which is incorporated into a curdlan biocompatible matrix. The developed nanocomposites are evaluated for their antioxidant and antimicrobial activities, with a particular focus on their effectiveness against pathogenic bacteria. The applied method in this work combines green synthesis with the process of uniform distribution of nanoparticles to a biocompatible polymer, which is a way forward towards the design of efficient biocompatible antimicrobial systems. The Ag/VO nanoparticles prepared with green synthesis were characterized by UV-Vis absorption, FTIR, XRD, SEM, EDX, zeta potential, DLS, and TEM. It has also been established that the antimicrobial property of the curdlan matrix has been enhanced with the addition of Ag/VO nanoparticles in the incorporated curdlan composites. Ag/VO-curdlan also showed significantly enhanced antimicrobial activity against Gram-negative bacteria and Gram-positive bacteria thus implying enhanced antimicrobial action of the prepared nanocomposite by increasing the size of the bacterial zone of inhibition from 14.0 to 18.0 mm. Besides, the curdlan NC in the presence of Ag/VO demonstrated an even lower value of MIC against Rhizoctonia solani (140.156 μg/mL) in comparison with Ag/VO NC (226.413 μg/mL) thus predicting Augmented antifungal activity. Through performing TEM analysis, we have observed significant morphological changes in R. solani strain when the Ag/VO-curdlan NC was used. However, the Ag/VO-curdlan NC had a notably high antioxidant activity with IC of 0.302 mg/mL to DPPH radical scavenging assay. These results reaffirm the enhancement in antimicrobial properties when Ag/VO and curdlan work together and agree with the objective of this work to propose novel and worthwhile nanomaterials for potentially applicable areas like food packaging or agriculture with insignificant harm to the environment.