A colorimetric and fluorescent probe for sulfite/bisulfite based on conjugated benzothiazole derivative and imaging application in living cells

Design, Synthesis and Evaluation of Fluorescent Properties of Benzothiazole Derivatives

Fluorescence imaging is conducive to establish a bridge between molecular biology and clinical medicine, and provides new tools for disease process research, early diagnosis, and efficacy evaluation, because of the advantages of rapid imaging and nondestructive detection. Herein, a series of fluorescent molecules with thiadiazole, or thiazole, or benzothiazole cores were designed and synthesized to develop more excellent fluorescent molecules in bio-imaging. According to theoretical and experimental methods, we found that benzothiazole derivative 14 B with conjugate expansion by (4-aminophenyl) ethynyl group was the most excellent fluorescent molecule among all the investigated compounds and exhibited low cytotoxicity and strong blue and green fluorescence by confocal cell imaging.

Imaging and detection of sulfite in acute liver injury with a novel quinoxaline-based fluorescent probe

Herein, a novel fluorescent probe HZY was developed for monitoring the sulfite (SO₃^2-) dynamics. For the first time, the SO₃^2- triggered implement was applied in the acute liver injury (ALI) model. The levulinate was selected to achieve the specific and relatively steady recognition reaction. With the addition of SO₃^2-, the fluorescence response of HZY exhibited a large Stokes shift of 110 nm under the 380 nm excitation. The merits included high selectivity under various pH conditions. Compared with the reported fluorescent probes for sulfite, HZY indicated above-moderate performances including remarkable and rapid response (40 folds, within 15 min), and high sensitivity (limit of detection = 0.21 μM). Further, HZY could visualize the exogenous and endogenous SO₃^2- level in living cells. Moreover, HZY could gauge the changing levels of SO₃^2- in three types (induced by CCl₄, APAP, and alcohol) of ALI models. Both in vivo imaging and depth-of-penetration fluorescence imaging demonstrated that HZY could characterize the developmental and therapeutic status during the liver injury process by measuring the dynamic of SO₃^2-. The successful implementation of this project would promote the accurate in-situ detection of SO₃^2- in liver injury, which was expected to guide the pre-clinical diagnosis and clinical practice.

A novel dual-function probe for fluorescent turn-on recognition and differentiation of Al3+ and Ga3+ and its application

In this study, a novel dual-function probe BMP based on benzothiazole was easily synthesized and characterized through common optical technique. In the system consisting of DMF/H₂O (v/v, 2/3), probe BMP showed azure and blue-green to Al³⁺ and Ga³⁺, respectively. Besides, the binding ratios of BMP to Al³⁺ and Ga³⁺ were determined as 1:1, which confirmed by Job's plot. Furthermore, for Al³⁺ and Ga³⁺, the limit of detection (LOD) was determined to be 1.51 × 10^-6 M and 4.28 × 10^-6 M, respectively. Moreover, it was worth noting that BMP showed good performances in paper colorimetry, cell phone colorimetric identification and cell imaging.

A bis-chalcone based colorimetric probe for the selective detection of bisulfite/sulfite anions: exploring surfactant promoted Michael addition of anions to α, β-unsaturated ketones

A probe, (1E,4E)-1,5-di(thiophen-2-yl)penta-1,4-dien-3-one, was developed for rapid, colorimetric, and selective detection of bisulfite/sulfite anions in aqueous solutions. This probe is based on the Michael addition reaction which is favoured in the presence of cationic micellar medium CTAB. CTAB promoted Michael addition is an effective tool to determine SO₂ toxicity, which is mainly expressed in terms of collective concentration of bisulfite and sulfite anions. The probe showed high selectivity and sensitivity toward bisulfite and sulfite over other interfering anions, with a detection limit of 0.43 μM and 0.23 μM, respectively. The possible recognition mechanism of the probe and the analyte was illustrated by NMR, HR-MS, IR, and computational analysis. Moreover, this probe showed great potential for the detection of bisulfite/sulfite in real samples, such as crystal sugar and brown sugar.

A novel ratiometric sensor prepared based aggregation-induced emission for ultrafast detection of SO2 derivatives in food samples and living cells

As one of the gaseous signaling molecules, aberrant levels of SO₂ are usually associated with many diseases. it is of great significance to develop sensitive methods for detection SO₂ on real. In this paper, a D-π-A near-infrared aggregation-induced fluorescent probe (DPA-CN) was built using diphenylamino-4-benzaldehyde and malononitrile for sensing SO₂. The DPA-CN exhibit AIE characterization that can quickly recognize SO₂ via the Michael addition mechanism. The DPA-CN displayed emission blue drift from 650 nm to 560 nm after adding SO₂, thereby realizing rapid and sensitive colorimetric detection of SO₂. The mechanism for recognition of SO₂ was verified via magnetic resonance imaging ⁽¹H NMR), electrospray ionization mass spectrometry (ESI-MS), scanning electron microscopy (SEM) and dynamic light scattering (DLS). The DPA-CN realized rapid and sensitive recognition of SO₂ with high specificity in 10 s within the concentration range of 0-100 μM. The limit of detection (LOD) is as low as 0.31 μM. Owing to its high sensitivity and low toxicity, the DPA-CN can be applied in monitoring of SO₂ in living cells and food analysis. Furthermore, the DPA-CN was used to prepare a visible and ultrafast semiquantitative paper-based SO₂ sensor with low cost and easy operation.

Colorimetric and Ratiometric Fluorescence Detection of HSO3- With a NIR Fluorescent Dye

Bisulfite (HSO₃^-) has been widely used in food and industry, which has brought convenience to human life, but also seriously endangered human health. In this work, the probe PBI was designed and synthesized to detect bisulfite (HSO₃^-) through nucleophilic addition reaction. The probe PBI showed a selective reaction to HSO₃^- and can quantitatively detect HSO₃^-. At the same time, the color of the probe PBI changed significantly, which provided a simple method for the naked eye to identify HSO₃^-. Finally, it was successfully applied to the fluorescence imaging of HSO₃^- in living cells.