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

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-pi-A fluorescent probe, , 3,4-dimethoxychalcone(DDP), , 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 H-1 NMR and C-13 NMR as well as MS. The push-pull-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 ' s plot and fluorescence titration. The limit of detection(LOD) ( LOD ) was 40.32 nmol/L, , and the binding constant was 3.95x10(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.