Synthesis and characterization of ultra-small superparamagnetic iron oxide nanoparticlesthinly coated with silica

Abstract

Ultra-small superparamagnetic iron oxide nanoparticles were synthesized byco-precipitation of iron chloride salts with ammonia and then encapsulated with thin(∼2 nm) layers of silica. The particles have been characterized for size, diffraction pattern,surface charge, and magnetic properties. This rapid and economical synthesis has a numberof industrial applications; however, the silica-coated particles have been optimized for usein medical applications such as magnetic resonance contrast agents and biosensors, and inDNA capturing, bioseparation and enzyme immobilization.