Dextran-based fluorescent nanoprobes for sentinel lymph node mapping.

Biopsy of sentinel lymph node (SLN) has become a common practice to predict whether tumor metastasis has occurred, so proper SLN positioning tracers are highly required. Due to many drawbacks of SLN tracers currently used, developing ideal, biosafe SLN imaging agents is always an urgent issue. The current study designed a novel fluorescent nanoprobe for accurate SLN mapping. Dextran-based nanogel (DNG) was prepared through a highly efficient self-assembly assisted approach and serves as a multi-functional platform for conjugating wide spectra emitting fluorescent agents. The newly fabricated fluorescent DNG (FDNG) could be designed with optimum size and stable fluorescent intensity for specific SLN imaging. Furthermore, a long-term dynamic course in vivo (from 1 min to 72 h) revealed the satisfactory specificity, sensitivity, and stability for SLN mapping. Most importantly, both in vitro and in vivo evaluations indicated that FDNG had fine biosafety and biocompatibility with lymphatic endothelial cells. All these results supported that FDNG could be used as highly efficient molecular imaging probes for specific, sensitive, stable, non-invasive, and safe SLN mapping, which provides efficient and accurate location for SLN biopsy and thus predicts tumor metastasis as well as directs therapies. Besides, our recent studies further demonstrated that DNG could also serve as a specific and controllable drug carrier, indicating a potential application for specific therapies of various lymph-associated diseases.