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

摘要

Ultra-small superparamagnetic iron oxide nanoparticles were synthesized by co-precipitation of iron chloride salts with ammonia and then encapsulated with thin (similar to 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 number of industrial applications; however, the silica-coated particles have been optimized for use in medical applications such as magnetic resonance contrast agents and biosensors, and in DNA capturing, bioseparation and enzyme immobilization.