γ-Ray synthesis of starch-stabilized silver nanoparticles with antibacterial activities

Silver nanoparticles (Ag NPs) are fabricated through gamma-irradiation reduction of silver ions in aqueous starch solutions. The UV-vis analyses show smaller sizes of Ag NPs produced, with higher yields, as the irradiation doses and/or Ag+ concentrations are increased. Higher concentrations of starch enhance the yields of Ag NPs, with no significant effects on their size. The most economical Ag NPs are produced at 5 kGy gamma-irradiation of a 2 X 10(-3) M solution of AgNO3 containing 0.5% starch. They show a relatively narrow size distribution, indicated by TEM and its corresponding size distribution histogram. The XRD pattern confirms the face-centered cubic (fcc) Ag NPs embedded in starch molecules. Interactions between these nanoparticle surfaces and starch oxygen atoms are indicated by FT-IR. Antibacterial activities of Ag NPs against Escherichia coli appear dependent on the gamma-ray doses applied. (C) 2008 Elsevier Ltd. All rights reserved.