Síntese de nanopartículas de prata mediada por extratos aquosos de açaí (Euterpe oleracea)

Abstract

The production of metallic nanoparticles (MNs) by green routes stands out for implementing concepts related to Green Chemistry in order to minimize impacts to the environment caused by using traditional synthetic methodologies. The use of plant extracts to mediate the synthesis of MNs is presented as an alternative because it contains secondary metabolites that can participate in the formation and stabilization of nanoparticles (NPs). In this scenario, açaí, a fruit native to the Amazon region that contains biomolecules with antioxidant properties, exhibits the potential to mediate the synthesis of NPs. The present study investigated the production of silver nanoparticles (AgNPs) mediated by aqueous extracts of açaí, assessing different reaction parameters (açaí extract concentration, pH and temperature). AgNPs were obtained after 1 day of reaction for all conditions tested, with plasmon band signal detected at the 350-450 nm range, especially when using more diluted extract conditions, and in neutral/alkaline medium at 25° C. These spheroidal AgNPs exhibited hydrodynamic diameters of 21.0 ± 0.8 nm (25°C); 9.0 ± 0.5 nm (40 °C) and 129.3 ± 5.6 nm (50 °C) and polydispersity indices (PdIs) of 0.283 ± 0.004 (25 °C), 0.452 ± 0.023 (40 °C) C) and 0.191 ± 0.017 (50 °C), with Zeta potential values close to -30 mV. The AgNPs showed lower cytotoxicity to fibroblasts than the AgNO3 solution, and did not exhibit microbiological activity, indicating a strong complexing capacity of the secondary metabolites present in the açaí extract.