Nowadays, in order to improve the diagnostic accuracy of the disease, more and more contrast agents have been applied in the clinical imaging modalities. A combination of nanotechnology with optical, computed X-ray tomography (CT), and magnetic resonance imaging (MRI) has great potential to improve disease diagnosis and therapy. Herein, we developed a novel multimodal contrast agent for deep-tissue bioimaging based on PEGylated Mn²⁺ doped NaLuF₄:Yb/Er nanoparticles (PEG-UCNPs). The multimodal nanoprobes have revealed the intensely red upconversion luminescence emission for deep-tissue upconversion luminescence (UCL) imaging. Moreover, Owing to the high longitudinal relaxivity, the PEG-UCNPs can be used as T₁-weighted MRI contrast agents. Additionally, with the high X-ray mass absorption coefficient of Lu³⁺, the novel nanoprobes are appropriate for CT imaging. With integration the high paramagnetic property, superior X-ray mass absorption coefficient and excellent upconversion luminescence in one system, the multimodal nanoprobes can provide a unique opportunity for MRI, CT and UCL imaging. More importantly, modification with PEG endows the novel nanoprobes with high biocompatibility, which would bring more opportunities for the biomedical applications in clinic.

如今，为了提高疾病的诊断准确性，越来越多的造影剂被应用于临床影像学检查中。纳米技术与光学，计算机X射线断层扫描（CT）和磁共振成像（MRI）的结合具有巨大的潜力，可以改善疾病的诊断和治疗。在这里，我们开发了一种新型的多峰造影剂，用于基于PEG化Mn ^2+的NaLuF ₄：Yb / Er纳米颗粒（PEG-UCNPs）的深部组织生物成像。多峰纳米探针已经揭示了用于深组织上转换发光（UCL）成像的深红色上转换发光。而且，由于高的纵向弛豫性，PEG-UCNP可以用作T _1。加权MRI造影剂。此外，由于Lu ³⁺具有较高的X射线质量吸收系数，因此新颖的纳米探针适用于CT成像。通过在一个系统中集成高顺磁特性，出色的X射线质量吸收系数和出色的上转换发光，多峰纳米探针可以为MRI，CT和UCL成像提供独特的机会。更重要的是，用PEG修饰赋予了新型纳米探针高生物相容性，这将为临床中的生物医学应用带来更多机会。