Structural and morphological investigations of β-cyclodextrin-coated silver nanoparticles

Abstract

This paper describes the synthesis of silver nanoparticles using an aqueous silver nitrate solution in the presence of glucose as a reducing agent, sodium hydroxide as a reaction catalyst and β-CD as a stabilizer. The structure and the morphology associated to the stabilizing layer around the silver nanoparticles were investigated. Raman spectroscopy confirmed the nanoparticle surface modification by β-CD, demonstrating the interaction between the β-CD rim hydroxyl groups and the AgNP surface. Transmission electron microscopy images showed an average 28.0nm diameter pseudo-spherical nanoparticles. Apart from this, a novel characterization of the β-CD layer surrounding the nanoparticles was carried out by using complementary analytical electron microscopy based on electron spectroscopy imaging in the transmission microscope. Mapping images revealed the presence of carbon and oxygen, demonstrating the existence of a uniform and interacting β-CD layer covering the nanoparticles. The antibacterial activity was also investigated and the β-CD-coated silver nanoparticles showed a promising bactericidal activity against the microorganism Escherichia coli.

Keywords: Antibacterial activity; Silver nanoparticles; Stabilizing layer; β-Cyclodextrin.