title: Microstructural, spectroscopic, and antibacterial properties of silver-based hybrid nanostructures biosynthesized using extracts of coriander leaves and seeds.
abstract: Coriander leaves and seeds have been highly appreciated since ancient times, not only due to their pleasant flavors but also due to their inhibitory activity on food degradation and their beneficial properties for health, both ascribed to their strong antioxidant activity. Recently, it has been shown that coriander leaf extracts can mediate the synthesis of metallic nanoparticles through oxidation/reduction reactions. In the present study, extracts of coriander leaves and seeds have been used as reaction media for the wet chemical synthesis of ultrafine silver nanoparticles and nanoparticle clusters, with urchin- and tree-like shapes, coated by biomolecules (mainly, proteins and polyphenols). In this greener route of nanostructure preparation, the active biocompounds of coriander simultaneously play the roles of reducing and stabilizing agents. The morphological and microstructural studies of the resulting biosynthesized silver nanostructures revealed that the nanostructures prepared with a small concentration of the precursor Ag salt (AgNO3=5 mM) exhibit an ultrafine size and a narrow size distribution, whereas particles synthesized with high concentrations of the precursor Ag salt (AgNO3=0.5 M) are polydisperse and formation of supramolecular structures occurs. Fourier transform infrared and Raman spectroscopy studies indicated that the bioreduction of the Ag-ions takes place through their interactions with free amines, carboxylate ions, and hydroxyl groups. As a consequence of such interactions, residues of proteins and polyphenols cap the biosynthesized Ag nanoparticles providing them a hybrid core/shell structure. In addition, these biosynthesized Ag nanomaterials exhibited size-dependent plasmon extinction bands and enhanced bactericidal activities against both Gram-positive and Gram-negative bacteria, displaying minimal inhibitory Ag concentrations lower than typical values reported in the literature for Ag nanoparticles, probably due to the synergy of the bactericidal activities of the Ag nanoparticle cores and their capping ligands.
authors.affiliation: Research Center of Mathematics and Physics, Faculty of Mathematics and Physics, Autonomous University of Nuevo León, Nuevo León, Mexico.
authors.forename: Carlos
authors.initials: C
authors.lastname: Luna
authors.affiliation: Central Laboratory of Analytical Instrumentation, Research Center for Applied Chemistry, Coahuila, Mexico.
authors.forename: Enrique Díaz
authors.initials: ED
authors.lastname: Barriga-Castro
authors.affiliation: Laboratory of Molecular Biology, Faculty of Chemistry, Autonomous University of Nuevo León, Nuevo León, Mexico.
authors.forename: Alberto
authors.initials: A
authors.lastname: Gómez-Treviño
authors.affiliation: Colloidal Materials Research Group, Institute of Materials Science of Seville, Spanish National Research Council, University of Seville, Seville, Spain.
authors.forename: Nuria O
authors.initials: NO
authors.lastname: Núñez
authors.affiliation: Research Center of Mathematics and Physics, Faculty of Mathematics and Physics, Autonomous University of Nuevo León, Nuevo León, Mexico.
authors.forename: Raquel
authors.initials: R
authors.lastname: Mendoza-Reséndez
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D028526:Coriandrum / Q000737:chemistry*; D006090:Gram-Negative Bacteria / Q000187:drug effects; D008024:Ligands; D053768:Metal Nanoparticles / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D012639:Seeds / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D008024:Ligands; D010936:Plant Extracts; D012834:Silver
keywords: bactericide; coriander; minimal inhibitory concentration; nanoparticles; silver