Nanosized silver-anionic clay matrix as nanostructured ensembles with antimicrobial activity.

Nanostructured ensembles of silver nanoparticles/zinc-substituted anionic clay matrix (Ag/ZnLDH) were obtained by a simple synthetic route in which reconstruction of the layered clay, synthesis of the silver nanoparticles and their organisation on the clay surface took place in a single step at room temperature. The morphology, composition and phase structure of the prepared powders were characterised by X-ray diffraction, infrared spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and N(2) adsorption. Results showed that the silver-anionic clay nanoarchitecture consists of nanoparticles of silver (average size 7 nm) deposited on the larger nanoparticles of clay (average size 85 nm). The antimicrobial activity was examined by disk diffusion assay and minimal inhibitory concentration determination as a function of x, where x is a controlled variable parameter that represents the length of time since the sample was synthesised. Ag/ZnLDH showed more stable antimicrobial properties than the unsupported nanosized silver.