Fast and Accurate Imaging of Lymph Node Metastasis with Multifunctional Near‐Infrared Polymer Dots

Abstract

AbstractMetastasis to regional lymph nodes is a significant prognostic indicator for cancer progression. There is a great demand for rapid and accurate diagnosis of metastasis to the lymph nodes. In this work, folate receptor‐targeted trimodal polymer dots are designed for near‐infrared (NIR)/photoacoustic (PA)/magnetic resonance (MR) imaging of lymph node metastasis. Confocal microscopic analyses and flow cytometry show that pulmonary mucosa epithelial cell carcinoma NCI‐H292 with expression of the folate receptor is positive for folate‐functional polymer dots. In vivo and ex vivo NIR imaging results verify that prepared polymer dots show rapid and high uptake in the metastatic lymph nodes, can effectively distinguish metastatic and normal lymph nodes for 1 h postinjection, and have great potential in real‐time imaging‐guided surgery. Furthermore, ten metastatic lymph nodes from the tumor‐bearing mice are detected by NIR imaging via intratumoral injection of polymer dots. Moreover, in vivo PA and MR imaging confirm the enhanced PA and MR signals of polymer dots in the metastatic lymph nodes as well as enlarged lymph nodes in tumor‐bearing mice. The results of this study provide a unique approach using trimodal polymer dots for the rapid and precise diagnosis of lymph node metastasis in vivo.