Search

It is highly indispensable to detect Cu2+ and S2− because of its vital role in living organisms and the environment. In this work, a novel “on-off-on” coumarin-based colorimetric fluorescent probe L for sequential recognition of Cu2+ and S2– was strategically designed and synthesized. It displays low detection limit measured to be 2 × 10−8 M and 6 × 10−8 M respectively for Cu2+ and S2– with high selectivity and excellent sensitivity. In addition, an appropriate broad pH of 4–10 allows probe L to be applied to the biological window, and MTT experiments show that probe L has negligible cytotoxicity, which demonstrate it can be employed to determine Cu2+ and S2– in A375 cells.

BF3 is an important catalyst in organic synthesis and petrochemicals which widely used in many chemical reactions. However, minor leaks may lead to serious environmental pollution and deadly biological damage. Therefore, how to quickly discover BF3 with high selectivity and sensitivity is of great significance and challenge. Here, we designed a BF3 specific fluorescent probe on the Rhodamine's switch ring process. In the presence of BF3, the fluorescence intensity showed a remarkable increase (200-fold) and the color of probe changed obviously with quick respond (

Hypochlorous acid (HClO) is identified as one of the most important reactive oxygen species (ROS) for its properties that reacts with various biomolecules in many processes of physiology and pathology. Accordingly, a new off-on fluorescent probe (E)-2-(3-(benzo[d]thiazol-2-yl)-2-hydroxybenzylidene)hydrazine-1-carboxamide (L) was designed and synthesized to detect HClO with excellent selectivity and good sensitivity in 100% aqueous solution. The probe L Exhibits 300-fold fluorescence enhancement at 465 nm in the presence of 40 μM HClO and the corresponding detection limit can reach 8.2 × 10−9 M. Moreover, the wide pH range of 5–11 makes probe L has excellent potential to be adapted in physiological system. More importantly, confocal fluorescence images and MTT assays indicate that this probe has outstanding membrane permeability and hypotoxicity, which demonstrate its potential applications in living cells.

A new turn-on fluorescence probe based on rhodamine 6G for Hg 2+ was synthesized and characterized by NMR, IR and ESI–MS. The probe L shows high selectivity and good sensitivity for Hg 2+ , which exhibited an obvious fluorescence change from colorless to pink in the presence of Hg 2+ . The detection limit was estimated to be 1.3 × 10 −9 M and the Job’s plot investigation suggested that L was bound to Hg 2+ with a simple 1:2 stoichiometry in EtOH/H 2 O (1:1, v/v) solution. Furthermore, biological experiments demonstrated that probe L has excellent membrane permeability and low cytotoxicity, which could be applied to monitor Hg 2+ in living cells, animal tissues and plant tissues.

A novel 2D lanthanide coordination polymer {Eu-CP (1)} based on a 3-bis(3-carboxyphenyl)imidazolium (L) ligand was successfully assembled through a solvothermal method. Luminescence tests indicate that 1 has excellent selectivity and sensitivity to detect Fe3+/Fe2+, Cr2O72−, and a series of nitroaromatic explosives. Interestingly, 1 can effectively distinguish CrVI anions (CrO42−/Cr2O72−), which is difficult for most of the reported CPs. Furthermore, in the detection process, 1 can be simply and quickly regenerated and reused at least five times. As far as we know, 1 is the first multifunctional Eu-CP used as a luminescent probe to detect Fe3+/Fe2+, Cr2O72−, and a series of nitroaromatic explosives (NAEs) based on the imidazolium derivative.

A novel rhodamine-benzothiazole fluorescent probe L was designed and synthesized which can be selective detection of three kinds of metal ions (Hg2+, Cr3+ and Al3+), through the mechanism of fluorescence resonance energy transfer (FRET). This probe L shows good sensitivity towards Hg2+, Cr3+ and Al3+ even at the sub-micromolar levels, which exhibited ratiometric fluorescence change from colorless to pink in aqueous media in a wide pH range of 5–10. Interestingly, the Job’s plot investigation suggested that L bounding to Hg2+ or Al3+ with a simple 1:1 mode and a 2:1 mode to Cr3+ display different binding modes. Furthermore, the potential utility for biological applications was performed by fluorescence microscopic imaging in live cells. The results indicated that fluorescence probe L was a hopeful candidate for applications in the cell-imaging and safety inspection.

Cys is one of the important biothiols and its abnormal concentration may pose a threat to human health. Therefore, the monitoring of Cys in organisms is of great significance. GSH and Hcy, as the other two biothiols, have similar chemical structures and active sites to Cys. Consequently, developing fluorescent probes to independently detect Cys has become a challenging problem. Keeping this in mind, α-β unsaturated ketone as a recognition group was integrated into the coumarin group skeleton to synthesize a fluorescent probe SC. After the nucleophilic addition reaction of Cys with SC, the conjugated system of SC was blocked and the fluorescent enhanced obviously. SC was able to detect Cys specifically under the same excitation with a low detection limit (11.1 nM). SC showed a rapid respond to Cys (120 s) and good fluorescent stability over a wide pH range. In addition, it achieved extracorporeal circulation in the presence of H2O2 or NEM. In the end, SC could be applied to detecting endogenous and exogenous Cys under biological condition due to its slight cytotoxicity and good biocompatibility. This provided a powerful tool for studying the physiological function of Cys exclusively.

Thiols play a vital role in both the physiological process and organic synthesis field, including aliphatic thiols (e.g., Cys, Hcy, and GSH) and thiophenols. As a result of the similarities of thiols in terms of molecular structure and chemical properties, it is difficult for conventional fluorescent probes to distinguish them, which hinders the progress of biological and pathological research. Keeping this in mind, a dual-site and dual-excitation fluorescent probe (YY) was designed to distinguish among Cys, Hcy, and thiophenols by three different reaction paths. When excited at 470 nm, YY only exhibits a fluorescence OFF–ON response toward thiophenols. However, when excited at 453 nm, YY not only displays a fluorescence OFF–ON response toward Hcy and thiophenols (λem = 499 and 561 nm) but also presents a two-stage fluorescence response toward Cys, which possesses a fluorescence OFF–ON response in the first stage (λem = 501 nm) and then a fluorescence ON–OFF response in the second stage (λem = 556 nm). Th...

Hydrogen sulfide (H2S) plays a vital role in numerous biological processes in living organisms. To better understand its functions, a fluorescent probe to fast and sensitively detect H2S is imminently needed. Keep this in mind, we reasonably designed probe DHC for detecting H2S based on α, β-unsaturated ethanoylcoumarin fluorophore. The limit of detection (LOD) is found to be as low as 5 × 10−8 M, which is superior to most reported fluorescent probes to detect H2S. Furthermore, the wide pH range of 4–11 makes it capable of application in biological systems. Most importantly, MTT assays and cell imaging experiments indicate that probe DHC has hypotoxicity and outstanding membrane permeability, which makes DHC successful imaging of H2S in Baby Hamster Syrian Kidney (BHK) cells.

By choosing 2-pyridin-4-yl-4,5-imidazoledicarboxylic acid (H3PIDC) as the first ligand and sodium oxalate (OX) as the ancillary ligand, a series of mixed-lanthanide metal-organic frameworks (M'LnMOFs) [Tb1-xEux(HPIDC)(ox)1/2H2O]·3H2O (x = 0 1, 0.01 2a, 0.03 2b, 0.05 2c, 0.08 2d, 0.1 2e, 0.3 2f, 0.5 2g, 1 3) have been successfully synthesized via hydrothermal reactions. 2a-2f can serve as ratiometric luminescent sensors for detecting temperature. In this co-doped system, 2d shows an excellent linear response relationship with temperature from 303 to 473 K and exhibits a maximum relative sensitivity (Sr) of 0.60% K-1 at 473 K. Furthermore, powder X-ray diffraction (PXRD) experiments indicate that 2d has excellent chemical stability under simulated physiological conditions and alkali-acid solutions with pH ranging from 4 to 11, which makes it suitable to be applied in the physiological environment.

To investigate the association between single nucleotide polymorphisms( SNPs) of 5, 10-methylenetetrahydrofolate reductase( MTHFR) C677T, A1298C, methionine synthase( MS) A2756G, methionine synthase reductase( MTRR) A66G and the risk of congenital heart disease( CHD).By restricting the corresponding conditions, a case-control study was performed. We collected 200 congenital heart disease children as case group and 200 normal children as control group admitted to the Department of cardiac surgery, Children 's Hospital of Hebei Province from January 2016 to April 2017. The genotype of MTHFR C677T, A1298C, MS A2756G, and MTRR A66G polymorphisms were detected by Sanger sequencing followed PCR. Assessing the relationships between 4 SNPs and the risk of whole CHD and different types of CHD.The mutant allete T of MTHFR C677T had contribute to the risk of developing CHD( OR = 2. 47, 95% CI 1. 86-3. 29, P0. 001). Compared with the wild CC genotype, heterozygosity CT had a higher risk of CHD( OR = 2. 32, 95% CI 1. 35-3. 98, P0. 05), the homozygous mutant genotype TT increased the risk of CHD by 5. 37( 95% CI 3. 01-9. 60, P0. 001). The mutant allele C of MTHFR A1298C was a protective factor for CHD( OR = 0. 53, 95% CI 0. 36-0. 77, P0. 05). Compared with the wild AA genotype, heterozygosity AC had a lower risk of CHD( OR = 0. 41, 95% CI0. 26-0. 64, P0. 001). After typing, the allele frequencies and genotypes frequencies of the above two SNPs were still statistically significant( P0. 05). The combined genotype analysis of the above two SNPs showed that: compared with the CC/AA genotype, individuals with CT/AA had a higher risk of CHD( OR = 4. 65, 95% CI 2. 16-10. 02), the TT/AA type increased to 7. 05( 95% CI 3. 37-14. 79). However, the polymorphisms of MS A2756G and MTRR A66G had no significant relationship with the risk of CHD( P0. 05).The mutant allele T of MTHFR C677T may be a risk factor for CHD and the mutant allele C of A1298C may be a protective factor for CHD. These two SNPs may have a joint effect on the occurrence of CHD.

A novel 2D lanthanide coordination polymer {Eu-CP (1)} based on a 3-bis(3-carboxyphenyl)imidazolium (L) ligand was successfully assembled through a solvothermal method. Luminescence tests indicate that 1 has excellent selectivity and sensitivity to detect Fe3+/Fe2+, Cr2O72-, and a series of nitroaromatic explosives. Interestingly, 1 can effectively distinguish CrVI anions (CrO42-/Cr2O72-), which is difficult for most of the reported CPs. Furthermore, in the detection process, 1 can be simply and quickly regenerated and reused at least five times. As far as we know, 1 is the first multifunctional Eu-CP used as a luminescent probe to detect Fe3+/Fe2+, Cr2O72-, and a series of nitroaromatic explosives (NAEs) based on the imidazolium derivative.