Water-dispersible stealth nanoparticle

Patent Pending PROBLEM TO BE SOLVED: To provide a technique for efficiently and easily synthesizing a water-dispersible stealth nanoparticle in which water solubility (water dispersibility) and an immune response evasion function (immune stealth capacity) is imparted to a nanoparticle having utility, particularly, a magnetic metal oxide nanoparticle by an inexpensive means in a large quantity. SOLUTION: The one in which one or a plurality of ligands imparting an immune response evasion function are bonded to the core of a metal oxide nanoparticle or a metal hydroxide nanoparticle as a single particle by a covalent bond or a strong bond equal to the covalent bond is a water-soluble immune response evasion surface-modified type metal oxide nanoparticle or immune response evasion surface-modified type metal hydroxide nanoparticle.