Valorisation of the Invasive Macroalgae Undaria pinnatifida (Harvey) Suringar for the Green Synthesis of Gold and Silver Nanoparticles with Antimicrobial and Antioxidant Potential

Bacterial and fungal infections are a challenging global problem due to the reported increasing resistance of pathogenic microorganisms conventional antimicrobials. Nanomaterials promising strategy fight caused by multidrug-resistant microbes. In this work, gold (Au@UP) silver (Ag@UP) nanoparticles were produced for first time green synthesis using an aqueous extract invasive macroalgae Undaria pinnatifida (UP). The characterized wide range physicochemical techniques. Au@UP Ag@UP demonstrated be spherical crystalline with average size 6.8 ± 1.0 nm 14.1 2.8 nm, respectively. Carbohydrates proteins UP may participate in capping nanoparticles. extract, Ag@UP, assessed their antimicrobial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, auris. showed highest very low MIC MBC values all tested bacteria, effective biofilm-producing bacteria. antifungal properties both remarkable, inhibiting hyphae formation. This study points towards biomedical exploitation brown algae.