@article{oai:repo.qst.go.jp:00046777,
 author = {Mi, Peng and Kokuryo, Daisuke and Cabral, Horacio and Kumagai, Michiaki and Nomoto, Takahiro and Aoki, Ichio and Terada, Yasuko and Kishimura, Akihiro and Nishiyama, Nobuhiro and Kataoka, Kazunori and 國領 大介 and 青木 伊知男},
 journal = {Journal of controlled release : official journal of the Controlled Release Society},
 month = {Nov},
 note = {Organic-inorganic hybrid nanoparticles with calcium phosphate (CaP) core and PEGylated shell were developed to incorporate magnetic resonance imaging (MRI) contrast agent diethylenetriaminepentaacetic acid gadolinium (III) (Gd-DTPA) for noninvasive diagnosis of solid tumors. A two-step preparation method was applied to elaborate hybrid nanoparticles with a z-average hydrodynamic diameter about 80nm, neutral surface ξ-potential and high colloidal stability in physiological environments by self-assembly of poly(ethylene glycol)-b-poly(aspartic acid) block copolymer, Gd-DTPA, and CaP in aqueous solution, followed with hydrothermal treatment. Incorporation into the hybrid nanoparticles allowed Gd-DTPA to show significant enhanced retention ratio in blood circulation, leading to high accumulation in tumor positions due to enhanced permeability and retention (EPR) effect. Moreover, Gd-DTPA revealed above 6 times increase of relaxivity in the nanoparticle system compared to free form, and eventually, selective and elevated contrast enhancements in the tumor positions were observed. These results indicate the high potential of Gd-DTPA-loaded PEGylated CaP nanoparticles as a novel contrast agent for noninvasive cancer diagnosis.},
 pages = {63--71},
 title = {Hydrothermally synthesized PEGylated calcium phosphate nanoparticles incorporating Gd-DTPA for contrast enhanced MRI diagnosis of solid tumors.},
 volume = {174},
 year = {2013}
}