resumo
Lamellar structured ultrathin manganese oxide nanoplates have been synthesized from thermal decomposition of manganese(II) acetylacetonate in the presence of 2,3-dihydroxynaphthalene, which promoted two-dimensional (2-D) growth by acting not only as a strongly binding surfactant but also as a structure-directing agent. Ultrathin manganese oxide nanoplates with a thickness of about 1 rim were assembled into a lamellar structure, and the width of the nanoplates could be controlled from 8 to 70 nm by using various coordinating solvents. X-ray absorption near-edge structure (XANES) spectra at the Mn K edge clearly showed that the nanoplates are mainly composed of Mn(II) species with octahedral symmetry. These hydrophobic manganese oxide nanoplates were ligand-exchanged with amine-terminated poly(ethyleneglycol) to generate water-dispersible nanoplates and applied to T1 contrast agents for magnetic resonance imaging (MRI). They exhibited a very high longitudinal relaxivity (r(1)) value of up to 5.5 mM(-1)s(-1) derived from their high concentration of manganese ions exposed on the surface, and strong contrast enhancement of in vitro and in vivo MR images was observed with a very low dose.
palavras-chave
MAGNETIC NANOPARTICLES; OPTICAL-PROPERTIES; NANOSHEETS; NANOTUBES; NANORODS; NANOCRYSTALS; MORPHOLOGY; NANOPRISMS; COMPLEXES; MOLECULES
categoria
Chemistry; Materials Science
autores
Park, M; Lee, N; Choi, SH; An, K; Yu, SH; Kim, JH; Kwon, SH; Kim, D; Kim, H; Baek, SI; Ahn, TY; Park, OK; Son, JS; Sung, YE; Kim, YW; Wang, ZW; Pinna, N; Hyeon, T
nossos autores
Nicola Pinna
InvestigadorGrupos
agradecimentos
We gratefully acknowledge the financial support by the Korean Ministry of Education, Science and Technology through National Creative Research Initiative (R16-2002-003-01001-0), Strategic Research (2010-0029138), and World Class University (R31-10013) Programs of National Research Foundation (NRF) of Korea.