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. The nanoparticle can be synthesized by subjecting a nanoparticle precursor solution, e.g., comprising metal salt including metal ions or the like to be a nanoparticle source to reaction treatment in a high temperature-high pressure water environment, e.g., in subcritical water or supercritical water in the presence of ligand molecules imparting immune response evasion capacity.COPYRIGHT: (C)2012,JPO&INPIT【課題】有用性を有するナノ粒子、特には磁性金属酸化物ナノ粒子に、水溶性(水分散性)と免疫応答回避機能(免疫ステルス能)を付与したものを、効率よく、安価な手法で、簡単に、且つ、大量に合成する技術の提供。【解決手段】一個又は複数個の免疫応答回避能を供与する配位子が、単一の粒子である金属酸化物ナノ粒子又は金属水酸化物ナノ粒子のコアに共有結合又は共有結合に匹敵する強い結合で結合しているものは、水溶性があり、免疫応答回避表面修飾型金属酸化物ナノ粒子又は免疫応答回避表面修飾型金属水酸化物ナノ粒子である。このものは、ナノ粒子源となる金属イオンなどを含む金属塩などを含有するナノ粒子前駆体溶液を、免疫応答回避能を供与する配位子分子の存在下に、高温高圧水環境下、例えば、亜臨界水又は超臨界水中で反応処理に付して合成することができる。【選択図】なし
