Activatable luminescent probes for imaging brain diseases

Abstract As the most pivotal organ of the human body, brain is susceptible to various disorder and trauma. Generally, brain diseases can be diagnosed only in the advanced stage where there is no treatment to fully cure these diseases. Although enormous efforts have been involved in the treatment of brain diseases over the years, it still acts as one of the most frequent causes of death and disability worldwide and is recognized as the largest and fastest growing field of unmet medical need. Hence early diagnosis is highly essential and crucial for prevention and treatment of brain diseases. Owing to their non-invasiveness and trackable signals, luminescent probes are particularly promising tools for brain disease diagnosis. Activatable luminescent probes can respond to specific pathologic stimuli and improve signal-to-background ratio of detection, permitting real-time semi-quantification of biomarkers and investigating pathological mechanism at the molecular level. Thus, activatable luminescent probes are of great importance to management of brain diseases and restoration of lost brain functions. In this review, we present the recent developments in this area, including blood-brain barrier (BBB)-crossing strategies and activation approaches of both molecular probes and nanoprobes for brain disease imaging.