Observation of the Elevation of Cholinesterase Activity in Brain Glioma by a Near-Infrared Emission Chemsensor

The excessive expression of cholinesterases (ChEs) directly disturbs the metabolism of acetylcholine (ACh), causing disordering neurotransmission in the brain or even Alzheimer's disease and cancer. However, the variation of ChEs including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in brain glioma has not yet been investigated. Therefore, the development of a suitable method for in situ imaging ChEs in brain tissues to understand the physiological functions of ChEs in depth is very important. Herein, a new near-infrared emission fluorescent probe (IPAN) for visualization of ChE activity was developed. IPAN exhibits ultrafast response to ChEs, low detection limit for AChE (0.127 U/mL) and BChE (0.0117 U/mL), and a large Stokes shift with near-infrared emission. Based on these excellent attributes, the IPAN was effectively utilized for imaging the fluctuations of ChE activity in the apoptosis cells and zebrafish. Notably, by utilizing the unique probe IPAN, we observed a significant enhancement of ChE activity in the tumor cells and brain glioma, for the first time. We believe that this interesting finding could provide a powerful guidance for tumor resection in the future.