coating nanoparticles

1. coating nanoparticles Magnetic nanoparticles, magnetite (Fe3O4) and maghemite (gFe2O3), have been the focus of research over the last decade due to their expansive applications in the field of targeted drug delivery, magnetic resonance imaging (MRI), cell labelling and separation, and hyperthermia treatment of cancer. Magnetic nanoparticles are superparamagnetic in nature; they are magnetized only upon application of an external magnetic field. Due to large surface area, magnetic nanoparticles are prone to oxidation by air and aggregation; this limits their use in biomedical applications. Various coating strategies have been employed to protect magnetic nanoparticles from oxidation and aggregation by using polymers and noble metals like gold, silica. Out of them, gold coating offers advantage of being chemically stable and biocompatible. It also provides the possibility of conjugating targeting ligands, drugs using gold-thiol chemistry, and for photothermal destruction of cancer cells. In gold coated magnetic nanoparticles, superparamagnetic nature of magnetic nanoparticles is retained with either a decrease or an increase in the value of saturation magnetization. http://www.cd-bioparticles.com/l/Gold-Coated-Magnetic-Nanoparticles_258_259_3 13.html