Magnetic nanoparticles and aqueous colloid composition containing the same

摘要

The present invention provides magnetic nanoparticles containing an iron alloy, or platinum and/or gold in addition to iron oxide, having a mean particle size of not less than 1 nm and not more than 20 nm and a coercivity of not less than 0.1 KA/m and not greater than 16 KA/m; and an aqueous colloid composition containing the magnetic nanoparticles. The magnetic nanoparticles have good stability in water and in electrolytic aqueous solutions such as blood, and are highly safe. The magnetic nanoparticles and the magnetic nanoparticle-containing aqueous colloid composition are useful as imaging agents and as thermotherapy formulations.