Antibacterial activity of biogenic gold, silver and silver/gold nanoparticles
Jarvy Francisco Cruz-Hernández, Maricela Villanueva-Ibáñez, Blanca Estela Jaramillo-Loranca
Polytechnic University of Pachuca/Research, Innovation and Postgraduate Department
In research on treatments against different diseases, nanotechnology has focused on studying materials at the nanometric scale, which have different properties from those of the same material in bulk. Nanoparticles (NPs) of noble metals such as gold (AuNPs), silver (AgNPs) and bimetallics (Ag/AuNPs) have gained great importance due to their applications in the medical field against bacteria, fungi and viruses with excellent results. In this work, mono and bimetallic nanoparticles were biosynthesized using the aqueous extract of green Coffea arabica beans as reducing agent. AuNPs and AgNPs were obtained with their respective methodologies, and for the Au/Ag composite material used a combined method that allowed to obtain hollow hexagonal nanoparticles. FT-IR analysis revealed C=O, CH3, CH2, NH2, and OH functional groups of extract biomolecules, such as chlorogenic acids and proteins, that interact with metal ions to biosynthesize the nanoparticles. Electron microscopy showed average particle sizes of 40 nm, 46 nm, and 55 nm for AgNPs, AuNPs, and Ag/AuNPs, respectively. AgNPs showed inhibition of the bacterial strains of Escherichia coli and Staphylococcus aureus, while for AuNPs and Ag/AuNPs the effect was not present. These studies provide information on the antibacterial effect of these biogenic nanoparticles.