Abstract Mesoporous GdPO4:Eu@SiO2@mSiO2 core-shell nanorods (NRs) were prepared by a facile two-step method. First, the monodispersed GdPO4:Eu NRs were obtained on a large scale via a facile precipitation method, then mesoporous silica was wrapped onto their surface through hydrolysis of tetraethylorthosilicate (TEOS). The XRD result indicates that the as-prepared GdPO4:Eu NRs core has hexagonal phase. The FTIR and the N2 adsorption/desorption isotherm analysis confirm the successful coating of mesoporous silica. The TEM images show that the obtained GdPO4:Eu@SiO2@mSiO2 NRs exhibit uniform monodisperse core-shell structure with a nanorod core (length of 200 nm; width of 20 nm), and mesoporous silica shell of 15 nm. Under excitation of 274 nm, GdPO4:Eu@SiO2@mSiO2 NRs show strong red luminescence from 5D0 →7FJ (J = 1, 2, 3 and 4) transitions of Eu3+. Furthermore, the GdPO4:Eu@SiO2@mSiO2 NRs exhibit obvious T1 enhancement effect due to paramagnetism of Gd3+. The drug loading capacity and pH-sensitive releasing behavior of the as-prepared GdPO4:Eu@SiO2@mSiO2 NRs were studied by using doxorubicin (DOX) as model drug. The excellent biocompatibility of GdPO4:Eu@SiO2@mSiO2 NRs was demonstrated by MTT assay. Taken together, the mesoporous GdPO4:Eu@SiO2@mSiO2 NRs may be potentially applied in fields of drug delivery and dual-modal imaging.

中文翻译：

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用于药物递送和细胞成像应用的介孔核壳结构 GdPO4:Eu@SiO2@mSiO2 纳米棒的合成

摘要 通过简便的两步法制备了介孔 GdPO4:Eu@SiO2@mSiO2 核壳纳米棒 (NRs)。首先，通过简便的沉淀法大规模获得单分散的 GdPO4:Eu NRs，然后通过原硅酸四乙酯 (TEOS) 的水解将介孔二氧化硅包裹在其表面。XRD 结果表明所制备的 GdPO4:Eu NRs 核具有六方相。FTIR 和 N2 吸附/解吸等温线分析证实了介孔二氧化硅的成功包覆。TEM 图像表明，所获得的 GdPO4:Eu@SiO2@mSiO2 NRs 具有均匀的单分散核壳结构，具有纳米棒核（长 200 nm；宽 20 nm）和 15 nm 介孔二氧化硅壳。在 274 nm 的激发下，GdPO4:Eu@SiO2@mSiO2 NRs 从 Eu3+ 的 5D0 →7FJ (J = 1, 2, 3 和 4) 跃迁处显示出强烈的红色发光。此外，由于 Gd3+ 的顺磁性，GdPO4:Eu@SiO2@mSiO2 NRs 表现出明显的 T1 增强效应。以阿霉素（DOX）为模型药物，研究了所制备的 GdPO4:Eu@SiO2@mSiO2 NRs 的载药量和 pH 敏感释放行为。MTT 分析证明了 GdPO4:Eu@SiO2@mSiO2 NRs 的优异生物相容性。综上所述，介孔 GdPO4:Eu@SiO2@mSiO2 NRs 有望应用于药物输送和双模态成像领域。