METHOD FOR PRODUCING NANOPARTICLES INCLUDING METAL PARTICLES CONTAINING IRON OXIDE HAVING AT LEAST ONE HYDROPHILIC LIGAND COORDINATED THERETO

[Problem]A novel method for producing a nanoparticle having a metal particle which contains iron oxide to which one or more hydrophilic ligands are coordination bonded is provided, where the nanoparticle is useful as a contrast agent for magnetic resonance imaging.[Means for Solution]As the novel method for producing a nanoparticle having a metal particle which contains iron oxide to which one or more hydrophilic ligands are coordination bonded, by performing ligand exchange to a hydrophilic ligand from an iron oxide nanoparticle having a surface to which a hydrophobic ligand is coordination bonded in one step using a phase transfer catalyst, it is possible to expect shortening of production processs and reduction of hydrophilic ligands used.Furthermore, by producing an iron oxide nanoparticle having a surface to which a hydrophobic ligand is coordination bonded using a dropwise addition method, it is possible to avoid a rapid temperature rise and a reaction at a high temperature of 200°C or higher, which is more advantageous for industrial production.