Recently, ultrathin two-dimensional (2D) nanomaterials have attracted considerable research interest in biomedical applications, owing to their intriguing quantum size and surface effects. In this work, a one-step “bottom-up” method is developed to prepare rare-earth (Gd³⁺ and Yb³⁺) co-doped layered double hydroxide (LDH) monolayer nanosheets, with a precisely controlled composition and uniform morphology. Due to the successful introduction of Gd³⁺ and Yb³⁺ into the LDH host layer, the Gd&Yb-LDH monolayer nanosheets exhibit excellent magnetic resonance (MR)/X-ray computed tomography (CT) dual-mode imaging functionality. Moreover, the Gd&Yb-LDH monolayer nanosheets achieve an ultrahigh loading of a chemotherapeutic drug (SN38) with a loading content (LC) of 925%, which is a one order of magnitude enhancement compared with previously reported delivery systems of hydrophobic drugs. Interestingly, by further combination with indocyanine green (ICG), in vivo tri-mode imaging, including CT, MR and near infrared fluorescence (NIRF) imaging, is achieved, which enables a noninvasive visualization of cancer cell distribution with deep spatial resolution and high sensitivity. In addition, in vitro and in vivo therapeutic evaluations demonstrate an extremely high tri-mode synergetic anticancer activity and superior biocompatibility of SN38&ICG/Gd&Yb-LDH. Therefore, this work demonstrates a paradigm for the synthesis of novel multifunctional 2D monolayer materials via a facile “bottom-up” route, which shows promising applications in cancer synergetic theranostics.

中文翻译：

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用于多模式成像和协同治疗的稀土水滑石单层纳米片的自下而上合成†

最近，超薄二维（2D）纳米材料由于其有趣的量子尺寸和表面效应而引起了生物医学应用领域的广泛研究兴趣。在这项工作中，开发了一种一步式“自下而上”的方法来制备稀土（Gd ³⁺和 Yb ³⁺）共掺杂层状双氢氧化物（LDH）单层纳米片，具有精确控制的成分和均匀的形貌。由于成功地将Gd ³⁺和Yb ³⁺引入LDH宿主层，Gd&Yb-LDH单层纳米片表现出优异的磁共振（MR）/X射线计算机断层扫描（CT）双模式成像功能。此外，Gd&Yb-LDH单层纳米片实现了化疗药物（SN38）的超高载量，载量（LC）为925%，与之前报道的疏水性药物递送系统相比提高了一个数量级。有趣的是，通过与吲哚菁绿（ICG）进一步结合，实现了体内三模式成像，包括CT、MR和近红外荧光（NIRF）成像，这使得癌细胞分布的无创可视化具有深空间分辨率和高灵敏度。此外，体外和体内治疗评估表明SN38&ICG/Gd&Yb-LDH具有极高的三模式协同抗癌活性和优异的生物相容性。因此，这项工作展示了通过简单的“自下而上”途径合成新型多功能2D单层材料的范例，这在癌症协同治疗诊断学中显示出有前景的应用。