A High‐Density Raman Photometry for Tracking and Quantifying of AchE Activity in The Brain of Freely Moving Animals with Network

Abstract A high‐density Raman photometry based on a dual‐recognition strategy is created for accurately quantifying acetylcholinesterase (AchE) activity in 24 brain regions of free‐moving animals with network. A series of 5‐ethynyl‐1,2,3,3‐tetramethyl‐based molecules with different conjugated structures and substitute groups are designed and synthesized for specific recognition of AchE by Raman spectroscopy. After systematically evaluating the recognition ability toward AchE, 2‐(4‐((4‐(dimethylamino)benzoyl)oxy)styryl)‐5‐ethynyl‐1,3,3‐trimethyl‐3H‐indol‐1‐ium (ET‐5) is finally optimized for AchE determination, which shows the highest selectivity, the greatest sensitivity, and the fastest response time among the investigated seven molecules. More interestingly, using the developed probe for AchE with high accuracy and sensitivity, the optimized AchE regulated by nitric oxide (NO) is discovered for promoting the neurogenesis of neural stem cells (NSCs). Benefiting from the high‐density photometry, it is found that the activity and distribution of AchE varied in 24 brain regions, and the levels of AchE activity in 24 brain regions of Alzheimer's mice (AD) are lower than those of normal mice. It is the first time that a functional network of AchE in 24 brain regions is established. It is also found that the loss of AchE functional network in AD mice is restored and reconstructed by the controlled release of AchE regulated by NO.