Green AgNPs from grapevine pruning waste: Synthesis and activity against P. aeruginosa

The scientific literature increasingly emphasizes environmentally sustainable treatments, circular economy principles, and effective waste management strategies. Grapevine ( Vitis vinifera ) is one of the most extensively cultivated crops worldwide, generating substantial amounts of waste rich in bioactive compounds. In this study, we investigate the stability and application of V. vinifera shoot extract for the green synthesis of silver nanoparticles (AgNPs). Key reaction parameters influencing nanoparticle stability—including temperature, pH, and light exposure—were systematically evaluated. Optimal synthesis was achieved at pH 7.5 and room temperature producing AgNPs with sizes ranging from 7 to 80 nm, depending on conditions. AgNPs synthesized at pH 7.5 exhibited excellent homogeneity and long-term stability, with no significant changes in UV-Vis absorbance after 24 months. Furthermore, the antibacterial activity of the AgNPs, the V. vinifera extract, and their combination was assessed against Pseudomonas aeruginosa strains. Our findings revealed a synergistic inhibitory effect, with the combined use of the extract and nanoparticles—without their separation from the reaction mixture—enhancing antimicrobial efficacy. This approach offers a promising and practical strategy for biomedical and environmental applications.