Preparation Of Benzopyronitrile Turn-on Near-infrared Fluorescence Probe And Its Imaging Application

Cysteine(Cys)which is an important biothiol in human body,plays a major role in many physiological and pathological processes and its concentration is also closely associated with a variety of diseases.Therefore,it is particularly important to develop a highly selective and sensitive detection method for cysteine detection,imaging and real-time monitoring.Organic small molecule near-infrared(NIR)fluorescence probes have high selectivity,sensitivity,strong anti-interference,good biocompatibility and strong tissue permeability,which show great application prospects in the field of biological detection and imaging.Herein,a novel xanthene-modified benzopyronitrile derivative enhanced near-infrared fluorescence probe(CP-NIR)was designed and synthesized for the detection of cysteine in biological system through Michael addition reaction.The probe was prepared by Knoevenagel reaction.The chemical structure of the probe CP-NIR was characterized by ~1H NMR and MS.Absorption and fluorescence spectra were used to investigate the spectral properties of CP-NIR,the selectivity to cysteine and the recognition mechanism of CP-NIR probe to cysteine.The biocompatibility of the probe was investigated by cytotoxicity test.The detection and imaging performance of the probe for cysteine were explored by fluorescence imaging experiments.The probe exhibits significant near-infrared fluorescence enhancement response signal,a large Stokes shift(160 nm),fast response time and low detection limit(48nM),thus achieving fast and selective enhanced fluorescence detection of cysteine.Low cytotoxicity and good cell permeability can be used for fluorescence imaging of cysteine in living cells.In addition,this near infrared fluorescence probe has been successfully applied to real-time monitoring and fluorescence imaging of abnormal concentration of endogenous cysteine in mouse models.