Theranostic Carbon Dots with Innovative NIR-II Emission for in Vivo Renal-Excreted Optical Imaging and Photothermal Therapy

Carbon dots (CDs) with low biotoxicity, high photostability, and well controlled size are highly desirable imaging agents for optical bioimaging. However, most of the CDs triggered by ultraviolet/blue light present visible/first near-infrared emissions shorter than 820 rim, impairing their imaging applications in vivo by low penetration depth. Hence, developing novel CD-based materials with second near infrared (NIR-II) emission located in 1000-1700 nm region is an urgent task. Here, a novel NIR-II-emitting CD-based nanoprobe triggered by 808 nm laser is developed. The designed CDs with 900-1200 nm luminescence possess high quantum yield (QY-0.4%) and high biocompatibility, which have proven to be effective probes for in vivo NIR-II bioimaging. Notably, nearly 65% CDs are excreted from mouse urine within 6 h, demonstrating the rapid renal clearance of CDs. Furthermore, the designed CDs also exhibit high photothermal efficiency (30.6%), making them ideal materials for thermal ablation of cancer. Our findings pave the way of designing a multifunctional CD-based theranostic platform for simultaneously integrating the photothermal therapy of cancer.