Síntese verde de nanopartículas de prata com extrato aquoso de folhas de Anacardium Occidentale, caracterização fisicoquímica e morfológica

Abstract

Nanoscience is an area of knowledge that studies the manipulation of materials at the atomic, molecular, and macromolecular scale. Nanotechnology is the sector that uses this knowledge to develop new materials and devices. A material is classified as nanometric if it has at least one of its dimensions located in the range between 1 and 100 nanometers (nm). In this size range, materials acquire different physicochemical properties. Biosynthesis is the process that uses organisms or parts of them, replacing chemical reagents, being a low-cost alternative, safe for humans and sustainable, since it minimizes the risks of damage to the environment in the manufacture of biomaterials. The present work aimed to synthesize and characterize silver nanoparticles using the aqueous extract of healthy leaves of Anacardium occidentale L. as a reducing agent. For the preparation of the extract, 10g of freshly collected leaves (fragmented into small pieces) were placed for infusion in 100 mL of ultrapure water and kept under agitation for 10 minutes at room temperature and subsequently filtered. A 10 mL aliquot of leaf extract was added to 30 mL of silver nitrate solution and kept under stirring for 10 minutes at 50°C. A change in color was observed, from a translucent solution to a dark yellow in the first eight minutes, indicating the beginning of the formation of nanoparticles. The solution was centrifuged several times to purify the silver nanoparticles. The physical-chemical characterization of the nanoparticles was carried out by spectrometric methods in the ultraviolet-visible region, where the solution presented an absorption peak of 428 nm, indicating the formation of silver nanoparticles and, in the infrared region, which indicated the immobilization of biomolecules of the extract on the nanoparticles. The results of infrared spectroscopy suggest that substances present in the extract acted as reducing and stabilizing agents. Topographic analysis by atomic force microscopy (AFM) showed that the nanoparticles had a spheroidal shape, with an average size of 87 nm in diameter. Plant extract-mediated synthesis of silver nanoparticles can replace some physicochemical methods currently used to produce nanoparticles. Therefore, A. occidentale is an excellent alternative for the synthesis of silver nanoparticles, environmentally acceptable and an excellent candidate for several biomedical applications