Manganese-enhanced MRI of rat brain based on slow cerebral delivery of manganese(II) with silica-encapsulated Mn x Fe(1-x) O nanoparticles.
In this work, we report a monodisperse bifunctional nanoparticle system, MIO@SiO2 -RITC, as an MRI contrast agent [core, manganese iron oxide (MIO); shell, amorphous silica conjugated with rhodamine B isothiocyanate (RITC)]. It was prepared by thermal decomposition and modified microemulsion methods. The nanoparticles with varying iron to manganese ratios displayed different saturated magnetizations and relaxivities. In vivo MRI of rats injected intravenously with MIO@SiO2-RITC nanoparticles exhibited enhancement of the T1 contrast in brain tissue, in particular a time-delayed enhancement in the hippocampus, pituitary gland, striatum and cerebellum. This is attributable to the gradual degradation of MIO@SiO2-RITC nanoparticles in the liver, resulting in the slow release of manganese(II) [Mn(II)] into the blood pool and, subsequently, accumulation in the brain tissue. Thus, T1-weighted contrast enhancement was clearly detected in the anatomic structure of the brain as time progressed. In addition, T2*-weighted images of the liver showed a gradual darkening effect. Here, we demonstrate the concept of the slow release of Mn(II) for neuroimaging. This new nanoparticle-based manganese contrast agent allows one simple intravenous injection (rather than multiple infusions) of Mn(II) precursor, and results in delineation of the detailed anatomic neuroarchitecture in MRI; hence, this provides the advantage of the long-term study of neural function.
['Chen|Wei|W|', 'Lu|Fang|F|', 'Chen|Chiao-Chi V|CC|', 'Mo|Kuan-Chi|KC|', 'Hung|Yann|Y|', 'Guo|Zhi-Xuan|ZX|', 'Lin|Chia-Hui|CH|', 'Lin|Ming-Huang|MH|', 'Lin|Yu-Hsuan|YH|', 'Chang|Chen|C|', 'Mou|Chung-Yuan|CY|']
D000818:Animals D001921:Brain D016923:Cell Death D003198:Computer Simulation D005290:Ferric Compounds D008099:Liver D008279:Magnetic Resonance Imaging D008345:Manganese D051379:Mice D008856:Microscopy, Fluorescence D041681:NIH 3T3 Cells D053758:Nanoparticles D051381:Rats D012235:Rhodamines D012822:Silicon Dioxide D013997:Time Factors
manganese slow release neuroarchitecture MEMRI brain image imaging agent magnetic nanoparticle silica sphere