In this study, we report on the synthesis, imaging, and radiosensitizing properties of ultrasmall β-NaGdF4:Yb50% nanoparticles as a multifunctional theranostic platform. The synthesized nanoparticles act as potent bimodal contrast agents with superior imaging properties compared to existing agents used for magnetic resonance imaging (MRI) and computed tomography (CT). Clonogenic assays demonstrated that these nanoparticles can act as effective radiosensitizers, provided that the nanoparticles are taken up intracellularly. Our ultrasmall β-NaGdF4:Yb50% nanoparticles demonstrate improvement in T1-weighted contrast over the standard clinical MR imaging agent Gd-DTPA and similar CT signal enhancement capabilities as commercial agent iohexol. A 2 Gy dose of X-ray induced ~ 20% decrease in colony survival when C6 rat glial cells were incubated with non-targeted nanoparticles (NaGdF4:Yb50%), whereas the same X-ray dose resulted in a ~ 60% decrease in colony survival with targeted nanoparticles conjugated to folic acid (NaGdF4:Yb50%-FA). Intravenous administration of nanoparticles resulted in clearance through urine and feces within a short duration, based on the ex vivo analysis of Gd3+ ions via ICP-MS. These biocompatible and in vivo clearable ultrasmall NaGdF4:Yb50% are promising candidates for further evaluation in image-guided radiotherapy applications.

中文翻译：

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用于双峰成像和放射增敏的可排泄、超小六方 NaGdF4:Yb50% 纳米颗粒

在本研究中，我们报告了作为多功能治疗平台的超小 β-NaGdF4:Yb50% 纳米粒子的合成、成像和放射增敏特性。与用于磁共振成像 (MRI) 和计算机断层扫描 (CT) 的现有试剂相比，合成的纳米颗粒可作为有效的双峰造影剂，具有优越的成像特性。克隆形成试验表明，这些纳米颗粒可以作为有效的放射增敏剂，前提是这些纳米颗粒被细胞内吸收。我们的超小 β-NaGdF4:Yb50% 纳米颗粒与标准临床 MR 显像剂 Gd-DTPA 相比，T1 加权对比度有所改善，并且与商业试剂碘海醇具有相似的 CT 信号增强能力。当 C6 大鼠神经胶质细胞与非靶向纳米粒子 (NaGdF4:Yb50%) 一起孵育时，2 Gy 剂量的 X 射线导致集落存活率降低 ~ 20%，而相同的 X 射线剂量导致集落存活率降低 ~ 60%与叶酸 (NaGdF4:Yb50%-FA) 结合的靶向纳米粒子的菌落存活率。根据通过 ICP-MS 对 Gd3+ 离子的离体分析，静脉注射纳米颗粒可在短时间内通过尿液和粪便清除。这些生物相容性和体内可清除的超小 NaGdF4:Yb50% 是在图像引导放射治疗应用中进一步评估的有希望的候选者。根据通过 ICP-MS 对 Gd3+ 离子的离体分析，静脉注射纳米颗粒可在短时间内通过尿液和粪便清除。这些生物相容性和体内可清除的超小 NaGdF4:Yb50% 是在图像引导放射治疗应用中进一步评估的有希望的候选者。根据通过 ICP-MS 对 Gd3+ 离子的离体分析，静脉注射纳米颗粒可在短时间内通过尿液和粪便清除。这些生物相容性和体内可清除的超小 NaGdF4:Yb50% 是在图像引导放射治疗应用中进一步评估的有希望的候选者。