808 nm light triggered lanthanide nanoprobes with enhanced down-shifting emission beyond 1500 nm for imaging-guided resection surgery of tumor and vascular visualization

Lanthanide based nanoprobe with high efficient down-shifting second near-infrared (NIR-II, 1000-1700 nm) emission has emerged as a promising agent for tumor-associated vascular visualization. However, most of the developed lanthanide-based NIR-II-emissive probes are activated by 980 nm laser, leading to the concern of biological overheating effect. Herein, the high quality 808 nm laser activated NaYF(4):Gd/Yb/Er/Nd/Ce@NaYF(4):Nd core-shell nanoprobes with significantly improved NIR-II emission beyond 1500 nm and eliminated overheating effect were developed for imaging-guided resection surgery of tumor and vascular visualization. Methods: The core-shell nanoprobe with boosted NIR-II emission and eliminated heating effect was achieved with combination of Nd-sensitizing and Ce-doping strategies. The NIR-II optical imaging and toxicity assessment were demonstrated by in vivo and in vitro experiments. Results: The designed core-shell nanoprobe presented superior NIR-II emission beyond 1500 nm than the core only nanoparticle and NIR-II emission intensity was improved up to 11.0 times by further suppressing the upconversion (UC) pathway through doping Ce(3+). More importantly, non-invasive tumor vascular imaging and NIR-II optical imaging-guided surgical resection of tumor were successfully achieved. Conclusion: It is expected that the Nd-sensitized lanthanide-based nanoprobe with significant improvement in NIR-II emission and eliminated overheating effect is a highly promising probe for NIR-II imaging, making it more competitive in non-invasive vascular imaging and imaging-guided tumor resection surgery.