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Fluorescent Magnetic Fe 3 O 4 /Rare Earth Colloidal Nanoparticles for Dual‐Modality Imaging
Author(s) -
Zhu Haie,
Shang Yalei,
Wang Wenhao,
Zhou Yingjie,
Li Penghui,
Yan Kai,
Wu Shuilin,
Yeung Kelvin W. K.,
Xu Zushun,
Xu Haibo,
Chu Paul K.
Publication year - 2013
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201300126
Subject(s) - superparamagnetism , materials science , fluorescence , nanoparticle , magnetic nanoparticles , luminescence , fluorescence lifetime imaging microscopy , colloid , nuclear magnetic resonance , analytical chemistry (journal) , nuclear chemistry , nanotechnology , magnetization , chemistry , optics , chromatography , organic chemistry , optoelectronics , physics , quantum mechanics , magnetic field
Fluorescent magnetic colloidal nanoparticles (FMCNPs) are produced by a two‐step, seed emulsifier‐free emulsion polymerization in the presence of oleic acid and sodium undecylenate‐modified Fe 3 O 4 nanoparticles (NPs). The Fe 3 O 4 /poly(St‐ co ‐GMA) nanoparticles are first synthesized as the seed and Eu(AA) 3 Phen is copolymerized with the remaining St and GMA to form the fluorescent polymer shell in the second step. The uniform core–shell structured FMCNPs with a mean diameter of 120 nm exhibit superparamagnetism with saturation magnetization of 1.92 emu/g. Red luminescence from the FMCNPs is confirmed by the salient fluorescence emission peaks of europium ions at 594 and 619 nm as well as 2‐photon confocal scanning laser microscopy. The in vitro cytotoxicity test conducted using the MTT assay shows good cytocompatibility and the T 2 relaxivity of the FMCNPs is 353.86 mM −1 S −1 suggesting its potential in magnetic resonance imaging (MRI). In vivo MRI studies based on a rat model show significantly enhanced T 2 ‐weighted images of the liver after administration and prussian blue staining of the liver tissue slice reveals accumulation of FMCNPs in the organ. The cytocompatibility, superparamagnetism, and excellent fluorescent properties of FMCNPs make them suitable for biological imaging probes in MRI and optical imaging.