Design and Synthesis of Flavone-based Fluorescent Probe for Cysteine Detection and Its Application in Living Cells Imaging

A highly selective and sensitive fluorescent probe 2-(2-furyl )-7-methoxychromone-3-acrylate (HFAC) was designed and synthesized with paeonol and furfural as raw material, 3-hydroxyflavone as fluorophore and acrylate group as recognition unit. The probe HFAC was characterized by H-1 NMR, C-13 NMR and HRMS-ESI. The results of absorption and fluorescence spectral analysis indicated that the probe had high sensitivity and selectivity towards cysteine (Cys), and the detection was not affected by other biothiols such as homocysteine, glutathione and others. Meanwhile, it was confirmed that HFAC was a reaction type "off-on" fluorescent probe, the fluorescence intensity at 525 nm had a high linear relationship with Cys concentration in the range of 20-400 mu mol/L with a regression equation of y = 0.4608x + 3.994 (R-2 = 0.9987) and a detection limit of 37. 9 nmol/L, and the color of the reaction solution changed from colorless to bright green at UV light of 365 nm. Fluorescence bioimaging experiment proved that probe HFAC had excellent cell membrane permeability, low cytotoxicity and biocompatibility, which was desirable for fast detection and visualization of both endogenous and exogenous Cys in A549 cells.