Modified polymer dots for multi-scale multi-modal imaging of lymphatic system in tumor pre-metastasis

Abstract Lymphatic system plays a vital role in facilitating tumor metastasis in the early stage. It is urgent to understand the structure, development and function of the lymphatics via the high-resolution and real-time imaging during the period. In this study, by using different ratios of polymer dots (Pdots) as nanoprobe, multi-scale multi-modal imaging methods are employed to observe the structure and function of the lymphatics in the tumor-bearing mice. Our findings demonstrate that the lymphatics display enlargement and thickening before the tumor metastasis. Moreover, the distortions, burrs, new-born branches and dysfunctional valves are observed. Furthermore, the combination of multiphoton confocal microscope and uDICSO realizes the complete transparency and super-resolution imaging of lymph nodes and lymphatic vessels together for the first time. These results show the exciting possibility of using functional Pdots for imaging the lymphatics in tumor metastasis, development and disease models in small animals.