Tryptophan / Dextran70 Based - Fluorescent Silver Nanoparticles: Synthesis and Physicochemical Properties.

Nano-size and shape of fluorescent silver nanostructures are important for a wide range of bio-applications, especially as drug delivery systems, imaging and sensing. The aim of the work is to develop a fluorescent silver nano-structured system, synthesized by chemical reduction of aqueous AgNO3 solution by Tryptophan using Dextran 70 as stabilizing agent (SNPsFL). The formed fluorescent nano-system was analyzed by UV-Vis absorption, DLS, SEM, TEM, AFM, steady-state and time resolved fluorescence spectroscopy. TEM analysis showed multi-twined nanoparticle, with the size within 15-40 nm. SNPsFL shows the fluorescence emission at 346 nm, the fluorescence quantum yield, Φ = 0.034 and the integrated fluorescence lifetime, <τ > = 1.82 ns. Riboflavin fluorescence behaviour in the RF/SNPsFL system, has been also studied. The results have relevance in using SNPsFL as a potential marker/emissive system to solve various biological barriers in humans, like drug release and protein structure.