Multimodal imaging-guided
therapy holds great potential for precise
theranostics of
cancer metastasis. However, imaging agents enabling the convergence of complementary modalities with therapeutic functions to achieve perfect
theranostics have been less exploited. This study reports the construction of a multifunctional nanoagent (FIP-99mTc) that comprises Fe3O4 for magnetic resonance imaging, radioactive 99mTc for single-photon-emission computed tomography, and
IR-1061 to serve for the second near-infrared fluorescence imaging, photoacoustic imaging, and
photothermal therapy treatment of
cancer metastasis. The nanoagent possessed superior multimodal imaging capability with high sensitivity and resolution attributing to the
complement of all the imaging modalities. Moreover, the nanoagent showed ideal photothermal conversion ability to effectively kill
tumor cells at low concentration and power
laser irradiation. In the in vivo study, FIP-99mTc confirmed the fast accumulation and clear delineation of metastatic lymph nodes within 1 h after administration. Attributing to the efficient uptake and photothermal conversion, FIP-99mTc could raise the temperature of metastatic lymph nodes to 54 °C within 10 min
laser irradiation, so as to facilitate
tumor cell ablation. More importantly, FIP-99mTc not only played an active role in suppressing
cancer growth in metastatic lymph nodes with high efficiency but also could effectively prevent further lung
metastasis after resection of the primary
tumor. This study proposes a simple but effective
theranostic approach toward
lymph node metastasis.