Manganese porphyrin/ICG nanoparticles as magnetic resonance/fluorescent dual-mode probes for imaging of sentinel lymph node metastasis.

Diagnosis of sentinel lymph node (SLN) metastasis and its status are key parameters for predicting overall disease prognosis. In this work, Pluronic F127 stabilized ICG/tetra(4-carboxyphenyl)porphyrin-Mn(III) (TCPP(Mn)) nanoparticles (F127-ICG/Mn NPs) as fluorescent/magnetic resonance (FL/MR) dual-modality probes were prepared. The application of F127-ICG/Mn NPs in SLN imaging was mainly evaluated from two perspectives: the difference between the normal LN and the metastatic SLN and the difference between micrometastasis and macrometastasis. Normal and metastatic SLNs and micro- and macro-SLN metastasis were successfully distinguished through fluorescence and MR imaging with the help of F127-ICG/Mn NPs. In contrast, for the ICG group, the micro- and macro-SLN metastasis status could not be differentiated by fluorescence imaging. Besides, the lymph nodes can be stained green by the F127-ICG/Mn NPs and clearly visualized by the naked eye. In general, F127-ICG/Mn NPs demonstrated the potential of the preoperative diagnosis of SLN metastasis and its status, as well as intraoperative navigation by green-stained SLN and NIR FL imaging. This work provides a reference for developing multimodal nanoparticles for SLN metastasis diagnosis.