Near-Infrared Afterglow ONOO--Triggered Nanoparticles for Real-Time Monitoring and Treatment of Early Ischemic Stroke.

Early detection and drug intervention with the appropriate timing and dosage are the main clinical challenges for ischemic stroke (IS) treatment. The conventional therapeutic agents relay fluorescent signals, which require real-time external light excitation, thereby leading to inevitable autofluorescence and poor tissue penetration. Herein, we report endogenous peroxynitrite (ONOO-)-activated BDP-4/Cur-CL NPs that release NIR afterglow signals (λmax 697 nm) for real-time monitoring of the progression of ischemia reperfusion (I/R) brain injury while releasing curcumin for the safe treatment of IS. The BDP-4/Cur-CL NPs exhibited bright NIR afterglow luminescence (maximum 732-fold increase), superb sensitivity (LOD = 82.67 nM), high energy-transfer efficiency (94.6%), deep tissue penetration (20 mm), outstanding antiapoptosis, and anti-inflammatory effects. The activated NIR afterglow signal obtained in mice with middle cerebral artery occlusion (MCAO) showed three functions: (i) the BDP-4/Cur-CL NPs are rapidly activated by endogenous ONOO-, instantly illuminating the lesion area, distinguishing I/R damage from normal areas, which can be successfully used for endogenous ONOO- detection in the early stage of IS; (ii) real-time reporting of in situ generation and dynamic fluctuations of endogenous ONOO- levels in the lesion area, which is of great value in monitoring the evolutionary mechanisms of IS; and (iii) dynamic monitoring of the release of curcumin drug for safe treatment. Indeed, the released curcumin effectively decreased apoptosis, enhanced survival, alleviated neuroinflammation, reduced brain tissue loss, and improved the cognition of MCAO stroke mice. This work is the first example of afterglow luminescence for early diagnosis, real-time reporting, drug tracing, and treatment for IS.