title: Biocompatible silver nanoparticles prepared with amino acids and a green method.
abstract: The synthesis of nanoparticles is usually carried out by chemical reduction, which is effective but uses many toxic substances, making the process potentially harmful to the environment. Hence, as part of the search for environmentally friendly or green synthetic methods, this study aimed to produce silver nanoparticles (AgNPs) using only AgNO3, Milli-Q water, white light from a xenon lamp (Xe) and amino acids. Nanoparticles were synthetized using 21 amino acids, and the shapes and sizes of the resultant nanoparticles were evaluated. The products were characterized by UV-Vis, zeta potential measurements and transmission electron microscopy. The synthesis of silver nanoparticles with tryptophan and tyrosine, methionine, cystine and histidine was possible through photoreduction method. Spherical nanoparticles were produced, with sizes ranging from 15 to 30 nm. Tryptophan does not require illumination nor heating, and the solution color changes immediately after the mixing of reagents if sodium hydroxide is added to the solution (pH = 10). The Xe illumination acts as sodium hydroxide in the nanoparticles synthesis, releases H+and allows the reduction of silver ions (Ag+) in metallic silver (Ag0).
authors.affiliation: Department of Exact and Earth Sciences, Federal University of São Paulo, Diadema, São Paulo, Brazil.
authors.forename: Ricardo Almeida
authors.initials: RA
authors.lastname: de Matos
authors.affiliation: Department of Exact and Earth Sciences, Federal University of São Paulo, Diadema, São Paulo, Brazil. lccourrol@gmail.com.
authors.forename: Lilia Coronato
authors.initials: LC
authors.lastname: Courrol
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry; D055772:Green Chemistry Technology / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D012834:Silver / Q000737:chemistry*; D012835:Silver Nitrate / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D014364:Tryptophan / Q000737:chemistry; D014978:Xenon
chemical_list: D000596:Amino Acids; D001672:Biocompatible Materials; D014978:Xenon; D012834:Silver; D014364:Tryptophan; D012835:Silver Nitrate
keywords: Amino acid; Cystine; Histidine; Light; Methionine; Nanoparticle; Photoreduction; Silver; Tryptophan; Tyrosine