3,4-二甲氧基查尔酮荧光探针用于人血清白蛋白的检测

3,4-Dimethoxychalcone Fluorescent Probe for the Detection of Human Serum Albumin

人血清白蛋白(HSA)是人血清中含量最丰富的蛋白质,它参与许多重要的生理过程,也与某些疾病息息相关,是临床诊断的重要生物标志物.本文以结构简单、合成简便且荧光性质易调控的查尔酮化合物为荧光探针母体,通过在查尔酮的A环引入2个甲氧基获得一种用于HSA检测的D-π-A型荧光探针3,4-二甲氧基查尔酮(DDP);经1H NMR和13C NMR及MS表征确证了其结构.查尔酮A环甲氧基的引入可以调控探针的推拉电子效应及其对HSA的荧光响应性能.进一步利用紫外-可见吸收光谱和荧光光谱等方法研究了DDP的光谱性质及其与HSA的相互作用.DDP的荧光光谱分析结果表明,其荧光对溶剂的极性非常敏感,其荧光发射波长随溶剂极性增大而发生红移.DDP与HSA响应后荧光增强73倍,响应前后的荧光量子产率分别为0.2%和4.0%.DDP对HSA的响应有优异的选择性,响应速度快且响应后荧光稳定.经Job’s plot和荧光滴定实验确定了DDP与HSA结合的化学计量比为1∶1,检出限(LOD)为40.32 nmol/L,结合常数为3.95×10^(5) L/mol;并通过置换实验证明了DDP的结合位点是HSA的DS2区.该探针可实现对HSA的高灵敏度、高选择性检测.

Human serum albumin(HSA)is the most abundant protein in human serum,involved in many important physiological processes and closely related to many diseases.It is an important biomarker for clinical diagnosis.In this paper,the chalcone compounds with simple structure,easy synthesis,and easily regulated fluorescence properties were used as the fluorescent skeleton.A D-π-A fluorescent probe,3,4-dimethoxychalcone(DDP),was designed for the detection of HSA by introducing two methoxy groups to the A ring of chalcone.The structure of the probe was confirmed by 1H NMR and 13C NMR as well as MS.The push-pull electronic effect of the probe and its fluorescence response to HSA were modulated by the introduction of the two methoxy groups.UV-visible absorption spectroscopy and fluorescence spectroscopy were further used to investigate the spectral properties of DDP and its interaction with HSA.The fluorescence spectra of DDP showed that its fluorescence is highly sensitive to the polarity of the solvent,and its fluorescence emission wavelength undergoes a red-shift with the increase of solvent polarity.The fluorescence enhancement of DDP in response to HSA was 73-fold,and the fluorescence quantum yields before and after response to HSA were 0.2%and 4.0%,respectively.DDP has excellent selectivity in response to HSA with fast response and stable fluorescence.The binding stoichiometry ratio of DDP to HSA was determined to be 1∶1 by Job’s plot and fluorescence titration.The limit of detection(LOD)was 40.32 nmol/L,and the binding constant was 3.95×10^(5) L/mol.The binding site of DDP with HSA was verified to be DS2 region with the displacement test.This probe enables highly sensitive and selective detection of HSA.