STABILITY OF SYNTHESIZED SILVER NANOPARTICLES IN CITRATE AND MIXED GELATIN/CITRATE SOLUTION

The study focuses on an investigation of the influence of both citrate and mixed gelatin/citrate as a reductant and stabilizer on the colloidal stability of silver nanoparticles (AgNPs)synthesized by a chemical reduction of Ag+ ions after a short - (7th day) - and long - (118th day) - term storage. Formed AgNPs were characterized by a UV–vis Spectroscopy, Transmission Electron Microscope (TEM), Dynamic light scattering (DLS) and Zeta-potential (ZP). The obtained results revealed that a short-term stability of the synthesized AgNPs was greatly influenced by a citrate stabilizer with the absence of gelatin. Smaller-sized AgNPs (average particle diameter of 3 nm), roughly spherical in a shape, were obtained with a narrow size distribution. The very negative value of the Zeta-potential confirmed a strong stability of the citrate capped AgNPs. However, a surface coating of the AgNPs by a gelatin/citrate stabilizer was found to be a dominant contributor in improving a long-term stability of the AgNPs (average particle diameter of 26 nm). The use of gelatin in mixed stabilizer solution provided the AgNPs with higher monodispersity and a controllable size after both the short and long-term storage

Effect of the concentration of protein and nanoparticles on the structure of biohybrid nanocomposites

We present colloidal nanocomposites formed by incorporating magnetite Fe3O4nanoparticles (MNPs) with lysozyme amyloid fibrils (LAFs). Preparation of two types ofsolutions, with and without addition of salt, was carried out to elucidate the structureof MNPs-incorporated fibrillary nanocomposites and to study the effect of the presenceof salt on the stability of the nanocomposites. The structural morphology of theLAFs and their interaction with MNPs were analyzed by atomic force microscopy andsmall-angle x-ray scattering measurements. The results indicate that conformationalproperties of the fibrils are dependent on the concentration of protein, and the preciseratio of the concentration of the protein and MNPs is crucially important for the stabilityof the fibrillary nanocomposites. Our results confirm that despite the change infibrillary morphology induced by the varying concentration of the protein, the adsorptionof MNPs on the surface of LAF is morphologically independent. Moreover, mostimportantly, the samples containing salt have excellent stability for up to 1 year ofshelf-life