PROBLEM TO BE SOLVED: To obtain a composite particle that comprises an iron oxide particle having a surface thereof covered with a low-molecular weight compound, has a negative charge on the surface and is imparted with biocompatibility.SOLUTION: The composite particle comprises an iron oxide particle and a surface region composed of a compound represented by formula (1): R1-(CH2OH)4-CO-R2 (1). In the formula, R1 is CH2OH or COR3 and R2 and R3 are each independently selected from the group consisting of O-, OH, ONa, OK, OCa and OMg.COPYRIGHT: (C)2012,JPO&INPIT【課題】 酸化鉄粒子の表面が低分子化合物で被覆され、表面に負電荷を持ち、生体適合性を備えた複合粒子を得る。【解決手段】 酸化鉄粒子と、下記式(1)で表される化合物からなる表面領域と、を有する複合粒子とする。R1-(CH2OH)4-CO-R2 (1)(式(1)中、R1はCH2OH又はCOR3であり、R2及びR3はO-、OH、ONa、OK、OCa、及びOMgからなる群からそれぞれ独立して選択される。)【選択図】 図1
