A Ratiometric and Colorimetric Hemicyanine Fluorescent Probe for Detection of SO2 Derivatives and Its Applications in Bioimaging

Abstract

Based upon the intramolecular charge transfer (ICT) mechanism, a novel ratiometric fluorescent probe EB was developed to detect SO32−/HSO3−. The probe displayed both colorimetric and ratiometric responses toward SO32−/HSO3−. It displayed a quick response (within 60 s), good selectivity and high sensitivity (a detection limit of 28 nM) towards SO32−/HSO3−. The SO32−/HSO3− sensing mechanism was confirmed as the Michael addition reaction by ESI-MS. Moreover, the probe could be applied to measure the level of sulfite in real samples, like sugar and chrysanthemum, and it could also be used to detect SO32−/HSO3− in HepG2 cells through confocal fluorescence microscopy, which proved its practical application in clinical diagnosis.

Rational Design of A NIR Ratiometric Fluorescent Probe with Large Stokes Shift for Sulfite Detection

“…The cell imaging experiments were measured by a confocal laser scanning microscope (Nikon/A1 + N-SIM). The synthesized various compounds were characterized by 1 H NMR, 13 C NMR, and ESI-MS.…”

“…1 H NMR (400 MHz, DMSO-d 6 ) δ 8.21 (d, J = 16.1 Hz, 1H), 7.95-7.84 (m, 2H), 7.79 (s, 1H), 7.63 (dd, J = 6.2, 2.9 Hz, 2H), 7.41-7.31 (m, 2H), 7.04 (t, J = 7.4 Hz, 1H), 6.99-6.85 (m, 2H), 5.32 (s, 2H), 4.65 (q, J = 6.7, 6.2 Hz, 2H), 1.77 (d, J = 1.9 Hz, 6H), 1.43 (t, J = 7.2 Hz, 3H). 13 Synthesis of probe NBHy.-The synthetic procedures of probe NBHy was similar with probe BBHy. Compounds 1 (0.63 g, 2.0 mmol) and Compounds 3 (0.32 g, 1.5 mmol) in ethanol (20.0 ml) was added with piperidine (40 μl).…”

“…[7][8][9][10][11][12] And more and more researchers pay considerable attention to fluorimetry for its high sensitivity and selectivity, simple operation, non-invasiveness, real-time detection, and the desired spatiotemporal resolution. [13][14][15] In a word, fluorescent probes are being used as an effective molecular tool for the determination of various targets. 6,[16][17][18][19][20] Among them, ratiometric fluorescent probes based on the ratio of fluorescence intensity at two different wavelengths as a signal reference can exhibit less background interference and higher detection sensitivity.…”

Small-Molecule Fluorescent Probe for Detection of Sulfite

“…In 2019, Qin's group [70] developed a ratiometric fluorescent probe 37 that reacted with 500 µM SO 3 2− and the color of the solution changed significantly from pink to colorless, probe 37 has the advantages of low LOD, high sensitivity, and high selectivity in HepG2 cells, and detects SO 3 2− /HSO 3 − reaction very quickly (within 60 s). In contrast to probe 37, probe 38 [71] applied HSO 3 − fluorescence imaging in live mice, which was the first time used for imaging BALB/c mice to detect SO 3 2− /HSO 3 − in live mice.…”

Development of a Ratiometric Fluorescent Probe with Zero Cross-Talk for the Detection of SO2 Derivatives in Foods and Live Cells

“…Thus far, a surging number of fluorescent probes have been developed as powerful tools for the determination of HSO 3 – /SO 3 2– based on nucleophilic addition, − deprotection reaction, , hydrogen bonding recognition, , and other chemical reaction mechanisms. , Regretfully, most of them mainly depended on single fluorescence signal changes, which are easily interfered by probe concentration, instrumental artifacts, and variations in cellular medium, thus hampering the reliability of the fluorescent assay. ,− To address this issue, ratiometric fluorescence probes with two different emission intensities, which could afford a built-in correction property and eliminate environmental effects, − are popular nowadays. Unfortunately, most of these ratiometric fluorescent probes are subjected to relatively small emission shifts (<100 nm), which will bring about a dilemma of self-absorption and low signal-to-noise ratios. − Most of the large-emission-shifted ratiometric fluorescence probes for the visualization of HSO 3 – /SO 3 2– , however, suffer from short-wavelength emission spectra or two-wavelength excitation, − limiting their further application in subcellular levels. Thereby, the development of a ratiometric fluorescence chemosensor for addressing the above issues and monitoring HSO 3 – /SO 3 2– levels in foods and live cells is necessary and urgent.…”