Development of BINOL-Si complexes with large stokes shifts and their application as chemodosimeters for nerve agent

Three fluorescent BINOL-Si complexes (FS1, FS2 and FS3) were rationally designed and synthesized to detect diethyl chlorophosphate (DCP), a mimic of lethal nerve agents. These three fluorescent probes showed green, yellow and orange fluorescence, respectively. Moreover, the series of fluorescent probes has the characteristics of fast response time (≤ 4 s), low detection limit (0.0097 μmol/L), high sensitivity and naked eye detection. More important, a fiber optic sensor capable of detecting DCP vapor in real time was also prepared for the first time, the lowest detection limits (down to 4.4 ppb) were all lower than that of the IDLH (immediately dangerous to life or health) concentration of Sarin (7.0 ppb).     

Syntheses of three terbium complexes as fluorescent probes and their application on the pH detection of routine urine test

By modifying the salicylic-acid moiety with electron-withdrawing or –donating groups, three new terbium complexes(L~Ⅰ·Tb, L~(Ⅱ)·Tb, L·~(Ⅲ)Tb) based on tripodal carboxylate ligands were synthesized. Due to different pull-push electronic effects of ligands, the fluorescence intensities of these terbium complexes significantly varied, that is: L~(Ⅱ)·Tb L~(Ⅲ)·Tb L~Ⅰ·Tb. Meanwhile, the characteristic peaks at 492 nm(~5D_4→~7F_6) and 547 nm(~5 D_4→~7F_5) showed "Off–On–Off" fluorescence response to various p H conditions,which indicated that all of them can be used as the highly sensitive pH fluorescent probes. Notably, using L~(Ⅱ)·Tb with the best fluorescence performance as a probe, some patients' urine samples can be easily monitored through the response triggered by pH value. Therefore, L~(Ⅱ)·Tb has the potential to auxiliarily diagnose some diseases in clinical practice through p H detection of routine urine test.     

A novel fluorescent probe with a large stokes shift for cysteine based on dicyanoisophorone

In this work, a dicyanoisophorone-based turn-on fluorescent probe, DCIP, for highly selective and sensitive detection of cysteine was designed based on nucleophilic substitution mechanism. Moreover, compared with typical cysteine probes, DCIP showed great selectivity and sensitivity for cysteine over other amino acids including the similar structured homocysteine (Hcy) and glutathione (GSH). Further, the detection limit toward cysteine was calculated to be as low as 0.70?μM. In addition, the utility of DCIP as a bioanalytical molecular tool was demonstrated by fluorescence imaging of biothiols in living cells.     

Ovalbumin-stabilized gold nanoclusters with ascorbic acid as reducing agent for detection of serum copper

Ovalbumin-stabilized gold nanoclusters(OVA@AuNCs) were prepared with ascorbic acid as a reducing agent. This strategy could realize the synthesis of water-soluble OVA@AuNCs within 20 min. The asprepared fluorescent probe showed a red fluorescence emission at 630 nm. Moreover, the properties of the OVA@AuNCs were characterized by transmission electron microscope, dynamic light scattering,ultraviolet-visible spectroscopy, fluorescent spectroscopy. Based on the surface electron density decrease-induced fluorescence quenching mechanism, the OVA@AuNCs provided high sensitivity and selectivity for sensing copper ions. A good linear relationship was obtained between the fluorescence intensity of OVA@AuNCs and the concentration of copper ions in the range of 5.0-100.0 μmol/L(R~2=0.999) with a detection limit of 640 nmol/L Furthermore, the rat serum copper contents were determined by using the OVA@AuNCs based assay, indicating great potential of fluorescent probes for application in biological and clinical analysis.     

Two chemodosimeters for fluorescence recognition of biothiols in aqueous solution and their bioimaging application

Two fluorescein derivatives containing 2,4-dinitrobenzenesulfonyl group have been developed as fluorescent probes to detect the biothiols (Cys, Hcy and GSH) in aqueous solution. Probes 1 and 2 can distinguish these biothiols in the presence of other amino acids. While probe 1 can recognize the biothiols in PBS/DMSO (v:v = 95:5, pH = 7.40) solution, notably probe 2 could be used in PBS buffer solution (pH = 7.40). The detection limit of Cys for probe 2 reached at 0.021 μM in aqueous solution, which was lower than the intracellular concentration of Cys. In the recognition process, a reaction between the probes and the biothiols occurred, in which the S–O bond was cleaved to remove 2, 4-dinitrobenzenesulfonyl group. The data of ¹H NMR, MS and DFT/TD-DFT calculation further confirmed the detection mechanism. Moreover, two probes were successfully applied to the HeLa cell imaging.     

New cytotoxic annonaceous acetogenin mimetics having a nitrogen-heterocyclic terminal and their application to cell imaging

A terminal unsaturated lactone or its equivalent is commonly believed to be essential for the cytotoxicity of natural annonaceous acetogenins and their artificial mimetics. In this work, we discovered a series of new cytotoxic ethylene glycol ether-containing mimetics, in which a variety of simple aliphatic nitrogen-heterocycles were introduced to replace the lactone terminal of AA005 (1), a representative bioactive polyether mimic identified from our previous research, for the first time. Among these, mimic 4 bearing a terminal piperazine was found to be the most potent compound against the proliferation of three cancer cells. Based on our new findings, a fluorescent probe 7 was also developed and successfully applied to the imaging of cancer cells. This work provides a new strategy for developing simpler cytotoxic mimetics of natural annonaceous acetogenins and molecular tools for biological imaging.     

Triarylcarbinol functionalized gold nanoparticles for the colorimetric detection of nerve agent simulants

Gold nanoparticles functionalized with a triarylcarbinol derivative have been used as colorimetric molecular probes for the naked-eye detection of the nerve agent simulants DCNP and DFP. The detection process is based on the compensation of charges at the surface of the nanoparticles which triggers their aggregation in solution with the resulting change in their plasmon band.     

Synthesis,characterization, and DNA binding of two copper(II) complexes as DNA fluorescent probes

[Cu(DAPT)₂Cl]Cl·H₂O and [Cu(DBM)(DAPT)Cl] [DAPT = 2,4-diamine-6-(pyrazin-2-yl)-1,3,5-triazine] were synthesized and characterized by IR and UV spectroscopy, elemental analysis, TG–DTA, molar conductivity, and LC–MS. The interaction with calf thymus DNA (ct-DNA) of the two complexes has been studied using UV spectra, fluorescent spectra, cyclic voltammetry, and viscosity measurements. The complexes interact with ct-DNA through classical intercalation. Fluorescence intensity changes of 1 and 2 in the absence and presence of ct-DNA have been investigated for quantitative determination of ct-DNA with the limit of detection of 3.8 and 7.7 ng mL^?1, respectively. From the result, the two complexes are potentially sensitive DNA fluorescent probes.     

Synthesis of 1,8-naphthalimide-based fluorescent nano-probes and their application in pH detection

Fluorescent nano-probes with particle sizes of 20 nm, 120 nm and 300 nm for proton were prepared through click reaction. The photophysical properties of the nano-probes were mainly affected by the particle size.     

Immunologically driven antibodies chemical engineering: design and synthesis of a hapten aimed at nerve agent hydrolysis

In this letter, we describe the design and the synthesis of an organophosphorus hapten aimed at a mixed biotechnological-chemical strategy for the mild decontamination of exceedingly toxic nerve agent VX. Hapten will be used to raise and select monoclonal antibodies (mAbs) able to bind both the nerve agent, and an oxime, derived from pyridinaldoxime, able to specifically hydrolyze its P-S bond. In order to significantly increase the hydrolysis reaction rate, the controlled respective positioning of the oxime and of the substrate will be achieved through the immunization, and in a second step, the oxime will be bound to the mAb in a reactive position towards the reactive thiophosphate functionality of the substrate.     

Development of a BODIPY-based ratiometric fluorescent probe for hypochlorous acid and its application in living cells

A BODIPY-based ratiometric fluorescent probe for HOCl has been designed based on the transduction of thioether to sulfoxide function. This probe features a marked absorption and emission blue-shift upon the HOCl-promoted rapid transduction, enabling the highly selective and ratiometric detection. In addition, the probe works excellently within a wide pH range of 4–10, addressing the existing pH dependency issue. Living cells studies demonstrate that the probe is cell membrane permeable and can be employed successfully to image endogenous HOCl generation in macrophage cells.     

Rational design of a bifunctional fluorescent probe for distinguishing Hcy/Cys from GSH with ideal properties

By pairing two fluoropho res according to their optical prope rties such as absorption spectral overlap and absorptivity,fluorescent quantum yield and emission spectral separation,a bifunctional fluorescent probe,TQBF-NBD,was rationally designed and synthesized to discriminatively sense Hcy/Cys and GSH with good selectivity and sensitivity.It is noted that this probe could work under a single-wave length excitation and displayed a mega-large Stokes shift.TQBF-NBD reacted with Hcy/Cys to give a mixed green-red fluorescence and displayed a red fluorescence upon the treatment with GSH.Distinguishable imaging of intracellular Hcy/Cys from GSH with the help of TQBF-NBD was realized in living cells and zebrafish.     

Reaction-based fluorescent probe for detecting of sulfur dioxide derivatives and hydrazine via distinct emission signals

Recently, the construction of multiple analytes responsive fluorescent probes with distinct emission signals has attracted widely attention. Thus, we have designed and synthesized a new fluorescent probe, 2-(2-hydroxyphenyl)benzothiazole dye skeleton (HBT-1), for the detection of sulfur dioxide and hydrazine. Significant fluorescence enhancements in two distinct emission bands (λ_em?=?464?nm and 498?nm) were generated when HBT-1 reacted with sulfur dioxide derivatives or hydrazine, respectively. Furthermore, the probe HBT-1 response can be saturated surpurisingly at the low concentration (100?μM), shorter reaction time for sulfur dioxide derivatives, while a longer reaction time and greater concentration (400?μM) for hydrazine. In other words, the probe HBT-1 can detect sulfur dioxide derivatives without hydrazine interference at low analyte concentrations.     

Tb~(3+)配合物修饰的磁性纳米荧光探针对水中Cu~(2+)的超灵敏检测

合成了一种Tb~(3+)配合物修饰的磁性纳米荧光探针cs124-DTPA-NH-PEGDBI-Fe3O4∶Tb。该复合荧光探针与Cu~(2+)有很强的结合能力,Cu~(2+)对Tb~(3+)配合物修饰的磁性纳米荧光探针具有荧光猝灭作用。实验表明,该复合荧光探针稳定性良好且有很好的水溶性,可在较宽的pH范围(5.0~10.0)快速检测Cu~(2+)。此外,在竞争实验中发现,该纳米荧光探针能够实现对溶液中Cu~(2+)的超灵敏和选择性检测而对其他多种常见离子响应较小,对Cu~(2+)的检测限甚至可达到1nmol/L。     

Formation of manganese-alkyne complexes mediated by trialkylmanganates and their application

Treatment of dodec-6-yne with triallylmanganate in the presence of 1,3,5-trimethylbenzene provides (Z)-dodec-6-ene. An addition of D₂O before quenching the reaction affords the corresponding dideuterated alkene. The result suggests the existence of the manganese-alkyne complex as an intermediate. Treatment of methyl propargyl ethers as alkynes with tributylmanganate generates propargylmanganese species. The reaction of non-2-ynyl tetrahydropyran-2-yl ether with tributylmanganate provides tetradec-7-yn-1,5-diol and 6-hexylocta-6,7-dien-1,5-diol.     

以苯并咪唑萘酰亚胺为荧光团高选择快速检测H2S的荧光探针

以1,8-萘二甲酸酐为起始原料合成一种萘酰亚胺衍生物3-叠氮基-7H-苯并[de]苯并[4,5]咪唑[2,1-a]异喹啉(DBNG),利用傅里叶变换红外光谱(FT-IR)和核磁共振波谱(NMR)等测试手段确定其结构,并将其作为小分子荧光探针用于检测H2S,系统研究了其荧光特性,结合理论计算,探究其可能的检测机制.结果表...     

Development of an autonomous detector for sensing of nerve agents based on functionalized silicon nanowire field-effect transistors

The ability to detect minute traces of chemical warfare agents is mandatory both for military forces and homeland security. Various detectors based on different technologies are available but still suffer from serious drawbacks such as false positives. There is still a need for the development of innovative reliable sensors, in particular for organophosphorus nerve agents like Sarin.We report herein on the fabrication of a portable, battery-operated, microprocessor-based prototype sensor system relying on silicon nanowire field-effect transistors for the detection of nerve agents. A fast, supersensitive and highly selective detection of organophosphorus molecules is reported. The results show also high selectivity in complex mixtures and on contaminated materials.     

Cu(II) complex of a flexible tripodal receptor as a highly selective fluorescent probe for iodide

A Cu(II) complex of a tripodal receptor bearing an anthracene moiety on one pod as a fluorophore was synthesized. The anion recognition behavior of the Cu(II) complex was evaluated in CH₃CN/H₂O (95:5, v/v), resulting in an extremely high selectivity for iodide over other anions such as F⁻, Cl⁻, Br⁻, , CH₃COO⁻, and . The Cu(II) complex acts as a selective probe for estimating iodide even in the presence of other anions without any interference.     

Fluorescent cyclodextrins bearing metal binding sites and their use for chemo- and enantioselective sensing of amino acid derivatives

Ditopic receptors based on cyclodextrins bearing a metal binding site were used as enantioselective fluorescence sensors, which were able to generate different responses in the presence of d- or l-amino acids. The performances of the selectors as a function of their structure were evaluated, and the same analysis was extended to other analytes. In this work, this approach is used for the enantiomers of a series of amino acid derivatives and in particular of 2-aminocaprolactam. The results showed that the ability of these sensors to perform enantiomeric analysis can be extended to other analytes of interest in organic synthesis such as amino acid amides and α-aminolactams.     

Acetylcholinesterase Based Dipsticks with Indoxylacetate as a Substrate for Assay of Organophosphates and Carbamates

Enzyme acetylcholinesterase (AChE) is an important part of cholinergic neurotransmission. It is targeted by many toxins such as nerve agents, organophosphates, and carbamate pesticides. Several drugs for treatment of Alzheimer's disease and Myasthenia gravis are also AChE inhibitors. The inhibitory effect can be used for assay purposes. The presented experiment is devoted to the construction of a colorimetric dipstick with immobilized AChE and using indoxylacetate as a chromogenic substrate. Standard qualitative cellulose filter papers, high-performance TLC plates, cotton gauze, and parafilm were chosen as matrices for the testing. The constructed dipsticks were created for assays of paraoxon as a model organophosphate pesticide and neostigmine as a model carbamate. The assessed limit of detection was 10^?7 mol/l for both inhibitors. It responds absolutely by detecting 4 pmol of inhibitor when a sample volume of 40 µL is considered. Long term stability and optimization of immobilization were also done and practical importance is discussed. The prepared dipsticks were also used for assays of paraoxon spiked tap and rain water. The suitability of the dipsticks for practical performance was approved. Intensive color changes from white to blue are suitable for scoring by a naked eye.