Abstract：
Diagnosing of lymph node metastasis is challenging sometimes, and multimodal imaging offers a promising method to improve the accuracy. This work developed porphyrin-based nanoparticles (68Ga-F127-TAPP/TCPP(Mn) NPs) as PET/MR dual-modal probes for lymph node metastasis imaging by a simple self-assembly method. Compared with F127-TCPP(Mn) NPs, F127-TAPP/TCPP(Mn) NPs synthesized by amino-porphyrins (TAPP) doping can not only construct PET/MR bimodal probes but also improve the T1 relaxivity (up to 456%). Moreover, T1 relaxivity can be adjusted by altering the molar ratio of TAPP/TCPP(Mn) and the concentration of F127. However, a similar increase in T1 relaxivity was not observed in the F127-TCPP/TCPP(Mn) NPs, which were synthesized using carboxy-porphyrins (TCPP) doping. In a breast cancer lymph node metastasis mice model, subcutaneous injection of 68Ga-F127-TAPP/TCPP(Mn) NPs through the hind foot pad, the normal lymph nodes and metastatic lymph nodes were successfully distinguished based on the difference of PET standard uptake values and MR signal intensities. Furthermore, the dark brown F127-TAPP/TCPP(Mn) NPs demonstrated the potential for staining and mapping lymph nodes. This study provides valuable insights into developing and applying PET/MR probes for lymph node metastasis imaging.
摘要：
淋巴结转移的诊断有时具有挑战性，多模态成像为提高精度提供了一种有前途的方法。这项工作通过简单的自组装方法开发了基于卟啉的纳米颗粒（68Ga-F127-TAPP/TCPP（Mn）NP）作为PET/MR双模式探针，用于淋巴结转移成像。与F127-TCPP(Mn)NP相比，通过氨基卟啉（TAPP）掺杂合成的F127-TAPP/TCPP（Mn）NP不仅可以构建PET/MR双峰探针，而且可以提高T1弛豫率（高达456%）。此外，T1弛豫率可以通过改变TAPP/TCPP(Mn)的摩尔比和F127的浓度来调节。然而,在F127-TCPP/TCPP（Mn）NP中未观察到T1弛豫率的类似增加，使用羧基卟啉（TCPP）掺杂合成。在乳腺癌淋巴结转移小鼠模型中，通过后足垫皮下注射68Ga-F127-TAPP/TCPP（Mn）NPs，根据PET标准摄取值和MR信号强度的差异,成功区分了正常淋巴结和转移淋巴结.此外，深棕色F127-TAPP/TCPP(Mn)NP具有染色和定位淋巴结的潜力.这项研究为开发和应用PET/MR探针进行淋巴结转移成像提供了有价值的见解。
