Facile and controllable one-step fabrication of selenium nanoparticles assisted by l-cysteine

A simple and solution-phase approach for large-scale synthesis of selenium nanoparticles (Nano-Se) by reducing sodium selenite (Na₂SeO₃) with l-cysteine has been demonstrated in this study. l-cysteine was used as both the reducing agent and surface modifier to control the formation of Nano-Se. The effects of reactant concentrations and ratios, and reaction time on the size and stability of Nano-Se were also investigated. The morphology and chemical composition of Nano-Se were characterized using various spectroscopic and microscopic methods. The results showed that varying the concentration ratio of l-cysteine to Na₂SeO₃ could control the diameter and morphology of Nano-Se, but not affecting their crystalline phases and chemical compositions. Monodisperse and homogeneous spherical Nano-Se with an average diameter of about 100 nm could be synthesized with the concentration ratio of l-cysteine to Na₂SeO₃ at 4:1. A striking feature of the as-synthesized Nano-Se was their good stability when dispersed in the reaction solutions, which indicates their potential in medical applications.