Abstract
The present work aims to prepare citrate-reduced silver particles (AgNPs) coated with poly(vinyl pyrrolidone) (PVP) and modified polyethylene thiol monomethylether. Modified AgNPs derivatives were exposed to synthetic human stomach fluid (SSF) (pH 1.5) and changes in size, shape, hydrodynamic diameter and chemical composition were determined during a 1 hour exposure period using UV-Vis, high resolution transmission electron microscopy/energy dispersive X-ray spectroscopy (TEM/EDS), dynamic light scattering (DLS) and X-ray powder diffraction (XRD) combined with Rietveld analysis. Exposure of AgNPs to SSF produced stabilized SPR peak at 414 nm which changed according to the exposure time and the conditions of preparation of AgNPs. Changes in aggregation and morphology of the particles were also observed as well as production of silver chloride which appeared physically associated with particle aggregates. The XRD data indicated that the there is no any silver oxide (Ag2O) particles formed or aggregated with silver nanoparticles.