Salgueiriño-Maceira Verónica, Correa-Duarte Miguel A, López-Quintela M Arturo, Rivas José
Departamento de Química Física y Física Aplicada, Universidade de Santiago de Compostela, E-15782, Santiago de Compostela, Spain.
J Nanosci Nanotechnol. 2009 Jun;9(6):3684-8. doi: 10.1166/jnn.2009.ns51.
Methods for the development of bifunctional magnetic and optically tunable nanoparticles with a structural design involving a magnetic iron oxide core (Fe3O4/gamma-Fe2O3) surrounded by a thick silica shell and further covered with an outer shell of optically active nanoparticles (CdTe quantum dots or gold nanoparticles) are reported. These highly fluorescent, optically tunable, and magnetic core-shell nanoparticles were synthesized from a modified Stöber method combined with the Layer-by-layer (LbL) assembly technique. Both types of particles were prepared through two main steps, including a controlled addition of tetraethoxysilane (TEOS) to a dispersion of Fe3O4/gamma-Fe,O3 nanoparticles, which were thereby homogeneously incorporated as cores into monodisperse silica spheres. The second step involved the LbL assembly of polyelectrolytes and luminescent CdTe quantum dots or Au nanoparticles onto the surface of the silica-coated magnetite/maghemite particles, which (for CdTe) were finally covered with an outer, protective silica shell. These spherical particles have a typical diameter of 220 and 230 +/- 10 nm, a saturation magnetization (Ms) of 1.34 emu/g at room temperature and a strong excitonic photoluminescence or an intense surface plasmon band.
报道了开发双功能磁性和光学可调纳米粒子的方法，其结构设计包括一个磁性氧化铁核（Fe3O4/γ-Fe2O3），周围包裹着一层厚厚的二氧化硅壳，并进一步覆盖有一层光学活性纳米粒子（CdTe量子点或金纳米粒子）外壳。这些高荧光、光学可调的磁性核壳纳米粒子是通过改进的Stöber方法与逐层（LbL）组装技术合成的。两种类型的粒子都通过两个主要步骤制备，包括将四乙氧基硅烷（TEOS）控制添加到Fe3O4/γ-Fe2O3纳米粒子的分散液中，从而将其作为核均匀地掺入单分散二氧化硅球中。第二步涉及将聚电解质和发光CdTe量子点或金纳米粒子逐层组装到二氧化硅包覆的磁铁矿/磁赤铁矿颗粒表面，（对于CdTe）最终用一层外部保护二氧化硅壳覆盖。这些球形颗粒的典型直径为220和230±10nm，室温下的饱和磁化强度（Ms）为1.34emu/g，具有强激子光致发光或强烈的表面等离子体带。
