A Single‐Wavelength Ratiometric NIR‐II Nanoprobe for Real‐Time Imaging of Neuroinflammation and BBB Disruption in Traumatic Brain Injury

ABSTRACT Traumatic brain injury (TBI) is a major cause of death and disability in children and young adults, leading to long‐term motor and cognitive dysfunction and neurodegeneration. Its pathological process is primarily driven by secondary neuroinflammation and oxidative stress. However, current clinical imaging lacks the resolution for real‐time monitoring of these early molecular events. Herein, we develop a microenvironment‐activatable NIR‐II nanoprobe (LnNPs‐IR775s‐ANG) based on a single‐wavelength ratiometric strategy for dynamic imaging of the key TBI biomarker‐hypochlorite (ClO − ). Leveraging the absorption competition‐induced emission (ACIE) effect, the probe enables self‐calibrated ClO − quantification via ratiometric fluorescence (F 1550, Ex808 /F 1550, Ex980 ), while the 980 nm signal serves as an indirect readout of BBB integrity. This integrated strategy allows simultaneous visualization of neuroinflammation and BBB disruption during TBI progression, offering a promising tool for early diagnosis, injury stratification, and therapeutic guidance.