Nanotechnology deals with the synthesis of materials and particles at nano-scale with dimensions of 1-100 nm. Nanoparticle synthesis is a revolution in the field of nanotechnology. Different types of metal salts are used to carry out the synthesis of metal nanoparticles. Silver, Gold, Copper, Zinc, Iron, Tungsten & Selenium etc. are some of the important metals for nanoparticle synthesis. The resulting effect of the nanoparticles depends upon the source from which they are synthesized and most importantly the metal which is being used for nanoparticle synthesis. Selenium nanoparticles (SeNPs) ranging in size from 30 to 300 nm can be produced by biological reduction of selenite. Selenium nanoparticles possess several activities. They have strong antimicrobial activities against several bacterial species and trypanosomes like Leishmania. SeNPs formed with Quercetin bind with the cell wall of bacteria and cause damage to bacterial cell membrane. SeNPs exhibit strong antiviral activities against H1N1 influenza virus by inhibiting the activities of neuraminidase and hemagglutinin. Anti-cancer and anti-tumor activities of SeNPs have also been reported. Transferrin conjugates with SeNPs and promotes the overproduction of Reactive Oxygen Species (ROS) in intracellular region and thus inducing cell apoptosis through MAPKs and p53 pathways. SeNPs also show anti-oxidative properties because they can significantly decrease the activity of peroxidases. SeNPs have several properties which have promising applications for future.

Keywords: Nanoparticles; Selenium Nanoparticles; Anti-microbial; Trypanosomes; Anti-oxidative