An Activatable NIR-II Nanoprobe for In Vivo Early Real-Time Diagnosis of Traumatic Brain Injury. Li Chunyan,Li Wanfei,Liu Huanhuan,Zhang Yejun,Chen Guangcun,Li Zijing,Wang Qiangbin Angewandte Chemie (International ed. in English) Traumatic brain injury (TBI) is one of the most dangerous acute diseases resulting in high morbidity and mortality. Current methods remain limited with respect to early diagnosis and real-time feedback on the pathological process. Herein, a targeted activatable fluorescent nanoprobe (V&A@Ag S) in the second near-infrared window (NIR-II) is presented for in vivo optical imaging of TBI. Initially, the fluorescence of V&A@Ag S is turned off owing to energy transfer from Ag S to the A1094 chromophore. Upon intravenous injection, V&A@Ag S quickly accumulates in the inflamed vascular endothelium of TBI based on VCAM1-mediated endocytosis, after which the nanoprobe achieves rapid recovery of the NIR-II fluorescence of Ag S quantum dots (QDs) owing to the bleaching of A1094 by the prodromal biomarker of TBI, peroxynitrite (ONOO ). The nanoprobe offers high specificity, rapid response, and high sensitivity toward ONOO , providing a convenient approach for in vivo early real-time assessment of TBI. 10.1002/anie.201911803

Controlled Synthesis of Ag Te@Ag S Core-Shell Quantum Dots with Enhanced and Tunable Fluorescence in the Second Near-Infrared Window. Zhang Yejun,Yang Hongchao,An Xinyi,Wang Zan,Yang Xiaohu,Yu Mengxuan,Zhang Rong,Sun Ziqiang,Wang Qiangbin Small (Weinheim an der Bergstrasse, Germany) Fluorescence in the second near-infrared window (NIR-II, 900-1700 nm) has drawn great interest for bioimaging, owing to its high tissue penetration depth and high spatiotemporal resolution. NIR-II fluorophores with high photoluminescence quantum yield (PLQY) and stability along with high biocompatibility are urgently pursued. In this work, a Ag-rich Ag Te quantum dots (QDs) surface with sulfur source is successfully engineered to prepare a larger bandgap of Ag S shell to passivate the Ag Te core via a facile colloidal route, which greatly enhances the PLQY of Ag Te QDs and significantly improves the stability of Ag Te QDs. This strategy works well with different sized core Ag Te QDs so that the NIR-II PL can be tuned in a wide range. In vivo imaging using the as-prepared Ag Te@Ag S QDs presents much higher spatial resolution images of organs and vascular structures as compared with the same dose of Ag Te nanoprobes administrated, suggesting the success of the core-shell synthetic strategy and the potential biomedical applications of core-shell NIR-II nanoprobes. 10.1002/smll.202001003