NIR-II Luminescent Nanothermometer for Precise Assessment of Ischemic Stroke

Ischemic stroke, an acute cerebral local blood circulation disorder caused by neurological deficit syndrome, has emerged as a prominent ailment that can affect the well-being and quality of life of the elderly. The difficulty in early assessment and narrow therapeutic time window can increase the risks of mortality and disability. Monitoring the temperature of brain microregions is a promising strategy for assessing the onset of an early stroke, which is positively correlated with the intricate immune response. In this study, an innovative hybrid nanothermometer combining lanthanides and quantum dots was established for contactless monitoring of cerebral lesion temperatures in mice with ischemic stroke. The output of ratio optical signals in the near-infrared-II window (1000-1700 nm) guaranteed deep penetration, high accuracy, and reduced tissue damage. An obvious temperature increase was detected in the minor middle cerebral artery occlusion model mice (4 h after reperfusion), indicating the occurrence of a minor stroke even in the absence of abnormal behaviors. Moreover, a further increase in the brain temperature of the ischemic region resulted in a more severe cerebral lesion, suggesting the potential advancement of the treatment window for early ischemic stroke. The proposed approach can enable precise assessment of ischemic stroke, with significant implications for the incidence and progression of the illness, ultimately enhancing the quality of life of affected patients.