Valorisation of the invasive macroalgae Undaria pinnatifida (Harvey) Suringar for the green synthesis of gold and silver nanoparticles with antimicrobial and antioxidant potential

• Autor(a) principal: González-Ballesteros, Noelia
• Data de Publicação: 2023
• Outros Autores: Fernandes, Mário, Machado, Raul, Sampaio, Paula, Gomes, Andreia C., Cavazza, Antonella, Bigi, Franca, Rodríguez-Argüelles, Maria Carmen
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/1822/86996
• topic: Undaria pinnatifida; Green synthesis; Silver nanoparticles; Gold nanoparticles; Antibacterial activity; Antifungal activity

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