Nanoparticle (NP) based contrast agents detectable via different imaging modalities (multimodal properties) provide a promising strategy for noninvasive diagnostics. Core–shell NPs combining optical and X-ray fluorescence properties as bioimaging contrast agents are presented. NPs developed earlier for X-ray fluorescence computed tomography (XFCT), based on ceramic molybdenum oxide (MoO₂) and metallic rhodium (Rh) and ruthenium (Ru), are coated with a silica (SiO₂) shell, using ethanolamine as the catalyst. The SiO₂ coating method introduced here is demonstrated to be applicable to both metallic and ceramic NPs. Furthermore, a fluorophore (Cy5.5 dye) was conjugated to the SiO₂ layer, without altering the morphological and size characteristics of the hybrid NPs, rendering them with optical fluorescence properties. The improved biocompatibility of the SiO₂ coated NPs without and with Cy5.5 is demonstrated in vitro by Real-Time Cell Analysis (RTCA) on a macrophage cell line (RAW 264.7). The multimodal characteristics of the core–shell NPs are confirmed with confocal microscopy, allowing the intracellular localization of these NPs in vitro to be tracked and studied. In situ XFCT successfully showed the possibility of in vivo multiplexed bioimaging for multitargeting studies with minimum radiation dose. Combined optical and X-ray fluorescence properties empower these NPs as effective macroscopic and microscopic imaging tools.

中文翻译：

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用于双模生物成像的光学和X射线荧光纳米粒子

可通过不同的成像方式（多峰性质）检测到的基于纳米粒子（NP）的造影剂为无创诊断提供了一种有前途的策略。介绍了结合了光学和X射线荧光特性的核-壳NP作为生物成像造影剂。基于陶瓷氧化钼（MoO ₂）以及金属铑（Rh）和钌（Ru）的较早开发用于X射线荧光计算机断层扫描（XFCT）的NPs涂有二氧化硅（SiO ₂）壳，使用乙醇胺作为溶剂。催化剂。事实证明，此处介绍的SiO ₂涂覆方法适用于金属和陶瓷NP。此外，将荧光团（Cy5.5染料）与SiO ₂共轭。在不改变杂化NP的形态和尺寸特征的情况下，使它们具有光学荧光特性。通过在巨噬细胞系（RAW 264.7）上进行实时细胞分析（RTCA），体外和不使用Cy5.5的SiO ₂包被的NPs的生物相容性得到了改善。共聚焦显微镜证实了核-壳纳米颗粒的多峰特性，从而可以追踪和研究这些纳米颗粒在体外的细胞内定位。原位XFCT成功展示了体内可能性用于最小辐射剂量的多靶点研究的多重生物成像。结合了光学和X射线荧光特性，使这些NP成为有效的宏观和微观成像工具。