Nanoparticles ranging from 0.1 nm to 1000 nm in size have demonstrated new physical and chemical properties. Semiconductor nanoparticles have excellent nonlinear properties, saturable absorption, and optical bistability. Selenium (Se), as a functional material, is an important elemental semiconductor attracting more attention owing to its special physical properties such as the anisotropy of thermo-conductivity, high photoconductivity (ca. 8 × 104 S cm−1), thermoelectric response, and nonlinear optical response. Therefore, Se is used in many applications ranging from photocells, photographic exposure meters, and solar cells to semiconductor rectifiers.

Furthermore, Se, as one of the essential trace elements, is confirmed to improve the activity of the seleno-enzyme and glutathione peroxidase prevention of free radical damage to cells and tissues in vivo . Since surface area-to-volume ratio increases with decreasing particle size, selenium nanoparticles have high biological activity, including anti-hydroxyl radical property and a protective effect against the oxidation of DNA.

In this study, researchers  report that selenium (Se) nanoparticles were first biosynthesized by Pseudomonas alcaliphila with a simple and eco-friendly biological method. The structural characteristics of Se nanoparticles were examined. The results showed that spherical particles appeared with diameters ranging from 50 to 500 nm during incubation and Se nanorods were present after incubating in an aqueous reaction solution for 24 h. However, the formation of Se nanorods was interrupted when 5% (w/v) poly(vinyl pyrrolidone) (PVP) was added in the aqueous reaction solution, obtaining stable spherical Se nanoparticles with a diameter of about 200 nm.

Researchers from Sichuan University and Chengdu Institute of Biology work together to study this job. It has been supported by National Natural Science Foundation of China and Chinese Academy of Sciences.