A natural cuttlefish melanin nanoprobe for preoperative and intraoperative mapping of lymph nodes

Lymphatic metastasis plays an important role in malignant tumor invasion. Efficient identification of sentinel lymph node (SLN) is extremely significant for designing therapeutic strategies and assessing prognosis. In this work, we developed a natural cuttlefish melanin nanoprobe for the preoperative and intraoperative evaluation of lymphatic metastasis. The cuttlefish melanin nanoparticle could improve the water-solubility and biocompatibility of the near-infrared-II (NIR-II) dye, and extend the retention time of small molecule dye. The NIR-II imaging results verified that the nanoparticles have a high accumulation, high sensitivity, and high signal-to-noise ratio in the lymphatic system. Moreover, the nanoparticles have obvious naked-eye identification potential due to their natural brownish-black color. Additionally, the nanoparticles can combine with Gd ions to achieve preoperative lymphatic magnetic resonance imaging (MRI). The results of this study provide a unique approach to effectively identify and accurately remove lymph nodes before operation and during surgery, exhibiting tremendous potential in clinical translation.