Long-term investigation on the phase stability, magnetic behavior, toxicity, and MRI characteristics of superparamagnetic Fe/Fe-oxide core/shell nanoparticles
Long-term investigation on the phase stability, magnetic behavior, toxicity, and MRI characteristics of superparamagnetic Fe/Fe-oxide core/shell nanoparticles
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DOI：
10.1016/j.ijpharm.2012.09.050
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发表时间：
2012-12-15
影响因子：
5.8
通讯作者：
Ahmadi, Reza
中科院分区：
文献类型：
--
作者：
Masoudi, Afshin;Hosseini, Hamid Reza Madaah;Ahmadi, Reza
为了有效地增强磁共振成像（MRI）获得的造影剂，制备了PEG包覆铁基纳米颗粒的药用级胶体分散体，并与传统的纯氧化铁造影剂进行了比较。在本研究中，我们在水介质中通过NaBH4还原氯化铁（III）合成了类似于14 nm的铁纳米颗粒。通过（CH3）(3)NO氧转移剂和暴露于氧气流两种不同的方法进一步氧化所得纳米颗粒。XRD和电镜分析证实在α - fe核表面形成了第二层。4个月后制备的纳米颗粒的磁性测量和穆斯堡尔光谱表明，在氧气流动中产生的2.3 +/- 0.5 nm的非晶态氧化壳不能保护内部金属铁不被氧化，导致样品的特性发生了剧烈变化。然而，（CH3）(3)NO得到的纳米颗粒具有3.6 +/- 0.4和4.5 +/- 0.7 nm的晶体氧化物外壳，即使在长期测试中也保持了其关键性能。此外，与纯氧化铁样品相比，核/壳纳米颗粒在4个月的MTT试验中没有发现明显的细胞毒性差异，并且在400 μ g铁浓度下，所有纳米颗粒的活力都低于50%。体外MR信号降低和相应的弛豫参数，特别是r(2)/r(1) > 2，确保了所有纳米颗粒都可以进行负对比增强。核/壳纳米颗粒在被检查大鼠腋窝和肱淋巴结的积累，以及纯氧化铁最低20%的造影剂增强表明这些材料作为潜在造影剂的效率。(C) 2012 Elsevier b.v.版权所有
To efficiently enhance the contrast obtaining from magnetic resonance imaging (MRI), pharmaceutical grade colloidal dispersions of PEG coated iron-based nanoparticles were prepared and compared to conventional pure iron oxide contrast agent. In this study, we synthesized similar to 14 nm iron nanoparticles via NaBH4 reduction of iron(III) chloride in an aqueous medium. The resulting nanoparticles were further oxidized by two different methods via (CH3)(3)NO oxygen transferring agent and exposure to oxygen flow. XRD and electron microscopy analyses confirmed the formation of a second layer on the surface of alpha-Fe core. As magnetic measurements and Mssbauer spectra of 4-months post prepared nanoparticles showed, 2.3 +/- 0.5 nm amorphous oxide shell produced in oxygen flow could not protect the inner metallic iron from oxidation and resulting sample suffered from drastic change in its characteristics. However, (CH3)(3)NO yielded nanoparticles with 3.6 +/- 0.4 and 4.5 +/- 0.7 nm crystalline oxide shells that retained their key properties even in long-term examinations. In addition, no significant difference was detected in cytotoxicity results of MTT assay test up to 4-months for core/shell nanoparticles, in comparison with pure iron oxide sample, and all fall below 50% viability in the iron concentration of 400 mu g. In vitro MR signal reduction and corresponding relaxometry parameters, especially r(2)/r(1) > 2, assure that all nanoparticles can be administrated for negative contrast enhancement. Accumulation of core/shell nanoparticles in axillary and brachial lymph nodes of examined rats and minimum contrast enhancement of 20% regarding to pure iron oxide implies the efficiency of these materials as potential contrast agent. (C) 2012 Elsevier B. V. All rights reserved.