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

• Published in: Marine Drugs
• Main Authors: González-Ballesteros, Noelia, Fernandes, Mário, Machado, Raul, Sampaio, Paula, Gomes, Andreia C., Cavazza, Antonella, Bigi, Franca, Rodríguez-Argüelles, Maria Carmen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Multidisciplinary Digital Publishing Institute (MDPI) 2023
• Subjects: Undaria pinnatifida; Green synthesis; Silver nanoparticles; Gold nanoparticles; Antibacterial activity; Antifungal activity; North Atlantic
• Online Access: https://hdl.handle.net/1822/86996; https://doi.org/10.3390/md21070397

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 Undaria pinnatifida (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 Escherichia coli , Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans , and Candida auris. 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. This workhas been funded by the Horizon Europe Project "PERSEUS" [grant number 101099423]. The UK participants are supported by UKRI [grant number 10073017], by Xunta de Galicia Ref.: ED431C 2018, the “Contrato-Programa” UIDB/04050/2020 through the FCT I.P., and project ATLANTIDA—the platform for the monitoring of the north Atlantic Ocean and tools for the sustainable exploitation of the marine resources operation NORTE-01-0145-FEDER-000040, cofinanced by NORTE2020 through the European Regional Development Fund (ERDF). NGB was financed by the Ministry of Universities under application 33.50.460A.752 and by the European Mar. Drugs 2023, 21, 397 16 of 18 Union ...