Department of Physics, University of Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy.
J Am Chem Soc. 2011 Nov 23;133(46):18626-33. doi: 10.1021/ja202466m. Epub 2011 Oct 25.
Magnetic/fluorescent composite materials have become one of the most important tools in the imaging modality in vivo using magnetic resonance imaging (MRI) monitoring and fluorescence optical imaging. We report herein on a simplified procedure to synthesize hybrid nanoparticles (HNPs) that combine silicon and magnetic iron oxides consisting of magnetite (Fe(3)O(4)) and maghemite (γ-Fe(2)O(3)). Intriguingly, our unique synthetic approach can control magnetic and optical behaviors by reducing the particle size, demonstrating that the HNPs with the mean diameter of 3.0 nm exhibit superparamagnetic behavior and green fluorescence in an aqueous solution, ambient air, and a cellular environment, whereas the HNPs with the mean diameter more than 5.0 nm indicate ferromagnetic behavior without fluorescence. Additionally, both HNPs with different diameters possess excellent magnetic responsivity for external applied magnetic field and good biocompatibility due to the low cytotoxicity. Our biocompatible HNPs with the superparamagnetism can provide an attractive approach for diagnostic imaging system in vivo.
磁性/荧光复合材料已成为利用磁共振成像（MRI）监测和荧光光学成像进行体内成像模式的最重要工具之一。我们在此报告了一种简化的方法来合成由磁铁矿（Fe3O4）和磁赤铁矿（γ-Fe2O3）组成的硅和磁性氧化铁的混合纳米粒子（HNPs）。有趣的是，我们独特的合成方法可以通过减小粒径来控制磁性和光学性能，证明平均直径为 3.0nm 的 HNPs在水溶液、环境空气和细胞环境中表现出超顺磁性和绿色荧光，而平均直径大于 5.0nm 的 HNPs 则表现出铁磁性而没有荧光。此外，由于低细胞毒性，两种具有不同直径的 HNPs 均对外加磁场具有出色的磁响应性和良好的生物相容性。我们具有超顺磁性的生物相容性 HNPs 可为体内诊断成像系统提供一种有吸引力的方法。
