OICC Press Journal of Nanostructure in Chemistry 2193-8865 10 3 (September 2020) 2020 06 16 The effect of Ag and clay nanoparticles on the antimicrobial activity of gamma-irradiated alginate/pectin beads 10.1007/s40097-020-00345-x EN Faten Ismail Abou El Fadl Polymer Chemistry Department, National Center for Radiation Research and Technology, Egyptian Atomic Energy Authority, Nasr City, Cairo, EG Radiation Chemistry Department, National Center for Radiation Research and Technology, Egyptian Atomic Energy Authority, Nasr City, Cairo, EG Sayeda Mohamed Ibrahim Polymer Chemistry Department, National Center for Radiation Research and Technology, Egyptian Atomic Energy Authority, Nasr City, Cairo, EG Radiation Chemistry Department, National Center for Radiation Research and Technology, Egyptian Atomic Energy Authority, Nasr City, Cairo, EG Journal Article 2020 06 16 Abstract In spite of the intensive work done on the preparation, characterization and applications of silver nanoparticles, the problems limit its use, still under study. One of these solutions is embedding Ag NPs in natural polymers to decrease aggregation, control its toxicity and size, and to increase its stability as well. In this respect, ionically cross-linked alginate/pectin (ALG/PEC) beads containing silver and clay nanoparticles, with different compositions were prepared. Silver nanoparticles have been obtained with hydrogel networks as nonreactors via in situ reduction of pre-adsorbed silver ions onto (ALG/PEC) beads matrix, using gamma irradiation. The effects of the composition of the two polymers, concentration of CaCl 2 as a crosslinking agent on the formation of cross-linked beads were studied. Characterization of (ALG/PEC) beads, (ALG/PEC)/Ag and (ALG/PEC)/Clay-Ag nanocomposite beads were performed using scanning electron microscopy, transmission electron microscopy and X-ray diffraction (XRD). The XRD pattern obtained confirmed the presence of diffraction peaks related to Ag NPs and nanoclay. The antimicrobial activity, toward different micro-organisms of the prepared nanocomposite beads was examined. The Beads containing both Ag NPs and Nanoclay exhibited the highest antimicrobial activity for the different organisms chosen for the antimicrobial test. Graphic abstract