title: Green biosynthesis of silver nanoparticles using Quercus brantii (oak) leaves hydroalcoholic extract.
abstract: BACKGROUND
  There is an ever-growing need to develop green, non-toxic, and eco-friendly procedures for synthesis and assembly of nanoparticles (NPs) with the desired morphologies and sizes. The hydroalcoholic extract of Persian oak leaves [Quercus brantii Lindl. (Fagaceae)] contains high content of phenolic and flavonoid compounds with strong antioxidant activities, and it seems that this plant can be considered a good candidate for metal nanoparticle synthesis.
  
  
  OBJECTIVE
  The potential of Q. brantii leaves in the production of silver NPs and the effect of the extract ethanol concentration on the produced NPs were studied.
  
  
  METHODS
  Quercus brantii leaves were freshly collected, air-dried at room temperature, powdered, and sieved. Hydroalcoholic extracts (70% and 96%) were prepared by percolation of the plant powder. The reaction mixtures contained (final concentrations): AgNO3 (1 mM) as the substrate, plant extract as the biocatalyst, and phosphate buffer (pH = 7, 100 mM) as the reaction medium. Silver ions were determined using atomic absorption analysis. Particle size distribution of NPs was analyzed using Nano-Zeta Sizer (Malvern Instruments Ltd, Malvern, UK). Samples for TEM were prepared by drop-coating the silver nanoparticle suspensions onto carbon-coated copper grids.
  
  
  RESULTS
  Hydroalcoholic extract (96%) of Q. brantii successfully produced quite small (as small as 0.83 nm and the mean size of 6 nm), spherical, and poly-dispersed NPs with low aggregates. The conversion was fast and completed in 5 h.
  
  
  CONCLUSIONS
  This plant and the extraction method seem to be quiet attractive for industrial scale production of NPs.
authors.affiliation: Department of Genetics & Molecular Biology, Faculty of Medicine, Isfahan University of Medical Sciences , Isfahan , Iran .
authors.forename: Hassan
authors.initials: H
authors.lastname: Korbekandi
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Chitsazi
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Asghari
authors.forename: Rahim
authors.initials: R
authors.lastname: Bahri Najafi
authors.forename: Akbar
authors.initials: A
authors.lastname: Badii
authors.forename: Siavash
authors.initials: S
authors.lastname: Iravani
mesh_terms: D000431:Ethanol; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D029963:Quercus / Q000737:chemistry*; D012542:Scattering, Radiation; D012834:Silver; D012997:Solvents; D013054:Spectrophotometry, Atomic; D014867:Water
chemical_list: D010936:Plant Extracts; D012997:Solvents; D014867:Water; D000431:Ethanol; D012834:Silver
keywords: Bioreduction; flavonoids; green synthesis; nanoparticle synthesis; phenolic compounds; tannins