2785-06-0

The molecules of trans-isomer of styryl dye la, containing the benzo-18-crown-6 moiety and the methoxybenzothiazole residue with the //-octadecyl substituent, were shown to form stable, highly ordered monolayers at the water/air interface. Increasing the surface pressure of the monolayer results in the formation of the H-aggregated molecules of compound la. The H-aggregates tend to dissociate to the monomeric trans-form. when the monolayer forms in the Langmuir-Blodgett film (LB film). The light irradiation of the LB films leads to the partially reversible trans-cw-photoisomerization of compound la, whose efficiency is much lower than that observed in an acetonitrile solution of la. The aggregation of cis-la isomers in the LB film is suggested to hamper the reverse cis-rra/u-isomerization. The aggregation of trans-l molecules in the LB films does not occur in air, but, after dipping in an aqueous solution, molecules of the LB film slowly form J-aggregates. A model of the structural organization of trans-l molecules in the LB films was proposed.

This paper is focused on the description of the synthesis, spectroscopic and electrochemical properties, and the free radical photoinitiation abilities of new multi-cationic monomethine dyes. The new monomethine dyes were employed both as the visible light photoinitiators of acrylate monomer polymerization and as fluorescence probes for monitoring the progress of polymerization. A degree of polymer cure from the measurement of the changes in the probe emission intensity and position shift during the thermally initiated polymerization of monoacrylate was obtained. A distinct increase in the intensity of the dyes fluorescence was observed during polymerization when the degree of monomer conversion was gradually increasing. The second part of this work is the possibility of an application of the dyes synthesized in combination with borate anions, as photoinitiating systems. Novel multi-cationic monomethine dyes paired with n-butyltriphenylborate anions are very efficient visible light photoinitiators of free radical polymerization of acrylate monomers. Their photoinitiating abilities were compared with the photoinitiation ability of Rose Bengal derivative, e.g. typical triplet state photoinitiator. The addition of a second co-initiator to the two-component photoinitiating system (monomethine borate salts) enhances their photoinitiating abilities.

The increasing incidence of multidrug resistant bacterial infection renders an urgent need for the development of new antibiotics. To develop small molecules disturbing FtsZ activity has been recognized as promising approach to search for antibacterial of high potency systematically. Herein. series of novel quinolinium derivatives were synthesized and their antibacterial activities were investigated. The compounds show strong antibacterial activities against different bacteria strains including MRSA, VRE and NDM-1 Escherichia coli. Among these derivatives. compound bearin. 4-fluorophenyl group (A2) exhibite. superior antibacterial activity and its MICs to the drug-resistant strains are found lower than those of methicillin and vancomycin. The biological results suggest that these quinolinium derivatives can disrupt the GTPase activity and dynamic assembly of FtsZ, and thus inhibit bacterial cell division and then cause bacterial cell death. These compounds deserve further evaluation for the development of new antibacterial agents targeting FtsZ.

Fluorescent hybridization probes are important tools for rapid, specific and sensitive analysis of genetic mutations. In this work, we synthesized novel alkyne-modified styryl dyes for conjugation with pyrrolidinyl peptide nucleic acid (acpcPNA) by click chemistry for the development of hybridization responsive fluorescent PNA probes. The free styryl dyes generally exhibited weak fluorescence in aqueous media, and the fluorescence was significantly enhanced (up to 125-fold) upon binding with DNA duplexes. Selected styryl dyes that showed good responses with DNA were conjugated with PNA via sequential reductive alkylation-click chemistry. Although these probes showed little fluorescence change when hybridized to complementary DNA, significant fluorescence enhancements were observed in the presence of structural defects including mismatched, abasic and base-inserted DNA targets. The largest increase in fluorescence quantum yield (up to 14.5-fold) was achieved with DNA carrying base insertion. Although a number of probes were designed to give fluorescence response to complementary DNA targets, probes that are responsive to mutations such as single nucleotide polymorphism (SNP), base insertion/deletion and abasic site are less common. Therefore, styryl-dye-labeled acpcPNA is a unique probe that is responsive to structural defects in the duplexes that may be further applied for diagnostic purposes.

We have synthesized two-photon organic molecule probes (IMT-E and IMT-M), which selectively stain endogenous RNA in the nucleolus and cytoplasm of living cells in a short incubation time. Using these probes, bright two-photon excitation fluorescence (TPEF) images of living cells have been developed. Titrations and digest tests of ribonuclease indicate the markedly higher affinity of these probes for RNA, especially when using IMT-E. Upon binding to RNA, the fluorescence intensity of IMT-E increases by about 15-fold, showing that IMT-E is a turn-on probe for the detection of RNAs. MTT assays demonstrate that the mitochondria of cells maintain their electron mediating ability after being stained with the probes. These results demonstrate that IMT-E is an attractive two-photon turn-on fluorescent probe for visualizing RNA in living cells.

The universal fluorescent staining property of thiazole orange (TO) dye was adapted in order to be specific for G-quadruplex DNA structures, through the introduction of a styrene-like substituent at the ortho-position of the TO scaffold. This extraordinary outcome was determined from experimental studies and further explored through molecular docking studies. The molecular docking studies help understand how such a small substituent leads to remarkable fluorescent signal discrimination between G-quadruplex DNA and other types of nucleic acids. The results reveal that the modified dyes bind to the G-quadruplex or duplex DNA in a similar fashion as TO, but exhibit either enhanced or quenched fluorescent signal, which is determined by the spatial length and orientation of the substituent and has never been known. The new fluorescent dye modified with a p-(dimethylamino)styryl substituent offers 10-fold more selectivity toward telomeric G-quadruplexes than double-stranded DNA substrates. In addition, native PAGE experiments, FRET, CD analysis, and live cell imaging were also studied and demonstrated the potential applications of this class of thiazole-orange-based fluorescent probes in bioassays and cell imaging.

[Figure not available: see fulltext.] A benzothiazolium salt containing carbazole group has been synthesized in a good yield via simple condensation reaction. Its photophysical properties and affinity for cyanide anion (tetrabutylammonium cyanide) have been investigated. The compound exhibited quick and well visible UV/Vis absorption and fluorescence responses to cyanide anion in MeCN, as the yellow color faded and the orange fluorescence disappeared. The in situ analysis by 1H NMR indicated that the cyanide anion was added to the C=N bond in the benzothiazolyl group.

A coumarin-hemicyanine dye 1 was reported for ratiometric fluorescent detection of SO2 derivatives HSO3- and SO 32- based on a novel addition-rearrangement cascade reaction. The Royal Society of Chemistry 2013.

Heparin is widely used to anticoagulation treatment in clinic, while the overdoses of heparin can cause potentially catastrophic complications. Thus, the selective and sensitive detection of heparin is of great importance. Herein, a novel water-soluble AIE-based fluorescent probe (TIBI) with red emission (650 nm) has been rationally developed to detect heparin by the electrostatic-interaction and ion replacing strategy. TIBI exhibited excellent selectivity and low detection limit (0.08 μM) for detection of heparin. Moreover, TIBI was successfully applied to detect heparin in complicated serum samples with satisfactory results. This study holds great promise for real time monitoring heparin in clinical application.

Quinoline appended hemicyanine 6MIM with strong ICT character was successfully synthesized through simple condensation reaction of 6-methoxy-2-chloro-3-formyl quinoline with 2-benzothiazolinium iodide. The photophysical characteristics of synthesized probe revealed that it would selectively detect glutathione (GSH) when it compared with different amino acids including biothiols and the detection limit is found to be 100 nM. The turn off sensor is due to thiol-halogen SNAr nucleophilic substitution between 6MIM and thiol group in glutathione. More importantly, the biosensor 6MIM was effectively applied in the fluorescence bioimaging of GSH in living cells with low cell toxicity. The colorimetric detectable color change of 6MIM-GSH has been effectively integrated with smartphone assisted RGB color value application with lowest detection value of 120 nM.

In the present work, thiazole functionalized receptors, S1 and S2, containing aminophenol as a signaling unit have been prepared and evaluated by UV–vis and fluorescence methods. These receptors consisting of conjugated benzothiazol-aminophenol system, which exhibited rapid and selective response towards cyanide anion. These two probes showed dramatic color change from wine red/purple to colorless, and optical quenching was also observed upon addition of CN? ions based on intramolecular charge transfer (ICT) transition in aqueous media. The detection limit of the probe S1 and S2 for CN? was calculated as 3.6 and 4.2 μM by spectrophotometric, 0.5 and 0.6 μM by spectrofluorophotometric methods, respectively. The binding stoichiometry between probes and cyanide was found to be 1:1, and the binding mechanism was also proposed.

A new carbazole derivative 2-[(1E)-2-[6-(benzothiazolyl)-9-ethyl-9H-(carbazol-3-yl)]-ethenyl]-3-methyl-benzothiazolium iodide (BCB) was synthesized and its anion sensing properties were studied. BCB acts as an efficient colorimetric and ratiometric fluorescent probe used for the detection of cyanide ions in an aqueous solution even in the presence of other anions such as F-, AcO-, H2PO4-, SO42-, SO32-, S2-, SCN-, Cl-, Br-, I-, N3-, ClO4-, NO2-, HCO3- and CO32-. The cyanide addition to the benzothiazolium group induces an obstruction of the intramolecular charge transfer (ICT) and produces a dramatic hypsochromic shift in the absorption (152 nm) and emission (165 nm) profiles of BCB. The change in color of the solution was prominent and could be easily observed by the naked eye. The BCB probe forms a 11 adduct with CN- with a detection limit of 0.09 μM. The probe was successfully applied for the detection of CN- in natural water samples as well as in live HeLa cells.

Substituted merocyanine dyes were obtained by Knoevenagel condensation between formylated arylbenzothiazole and quaternary 2-alkylbenzothiazoles. The condensations were performed in the presence of sodium methoxide and the products were obtained with exce

The near-IR dye thiazole green (TAG) was used as a monomeric nuclear staining dye for the low-level detection of DNA restriction fragments separated via high-performance capillary electrophoresis with near-IR laser-induced fluorescence detection. TAG poss

Cyanine based chemosensing platforms have successfully been employed over the past couple of decades in various fields of biomolecular sciences. Still a substantial number of recent advances and improvements on this class of compounds are reported in the art. This paper presents our latest work on the improved synthetic approach, study on photophysical properties, and biosensing applicability of monomethine cyanine dyes. The series of mono-, di- and tricationic dyes showed up to 5-fold enhanced resistance against photobleaching compared to the commercially available Thiazole Orange (TO). The title compounds were studied as potential molecular probes for the detection of deoxyribonucleic acid, demonstrating their capacity as excellent fluorescent labeling agents. Depending on the dye chemical structure, current Cl-TO compounds exhibit up to 834-fold enhanced fluorescence emission and form stable complexes with Calf Thymus-DNA. The calculated binding constants were found to be higher than several conventional fluorogenic dyes for nucleic acid detection. All studied derivatives appeared as less cytotoxic than the Thiazole Orange. IC50 concentrations in human fibroblasts MRC5 cell line were calculated up to 50 μM for the synthesized Cl-TO dyes, and 0.5 μM for the parental Thiazole Orange. Two of the dyes were found very competent in post-electrophoretic visualization of DNA. As demonstrated by the agarose gel electrophoresis, the staining efficiency and detection limits of the dyes were comparable to the widely used Ethidium Bromide. The tricationic dye revealed great potential for cell cycle analysis in G1, S and G2 phases. The chlorinated TO derivatives readily stain human cells in vivo, while they can effectively be applied for eukaryotic and microbial cell staining.

The stability in water of five styryl hemicyanine dyes containing benzoxazole, benzothiazole, benzoselenazole and oxazolopyridne rings with different substituents at different pH values has been investigated. All compounds are stable at acidic and neutral pH, however, at basic pH the oxazole dyes undergo a ring opening reaction. The stability at basic pH is increased by substituting the benzooxazolium with oxazolopyridium function in the oxazole dyes 3a and 3e. 1H and 1H DOSY solution NMR spectroscopy prove that slight structural changes result in significant differences in the process of self-association. The association constants for dimerization have been determined by curve fitting the concentration dependent 1H NMR spectra based on the isodesmic model. Van't Hoff analysis has been used to determine the thermodynamic parameters of the self-association process. The aggregation in water decreases with decreasing electronegativity and increasing the charge delocalization in the row (E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[d]oxazol-3-ium iodide (3a), (E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[d]thiazol-3-ium iodide (3b), (E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[1,3-d]selenazol-3-ium iodide (3d) in the oxazole/thiazole/selenazole analogues. Introducing methyl groups in the benzothiazole ring enhances stacking effects in water due to stronger hydrophobic character. This derivative is characterized by the highest self-association constant (ka = 299 L mol?1) and the lowest Gibbs energy (ΔG = -14 kJ mol?1). Substituting the phenyl with pyridyl ring in the oxazole analogue enhances significantly the solubility in water and thus decreases the self-association constant. Concentration dependent 1H ROESY spectra provide information about the orientation of the molecules in the stack.

Studies on small molecule fluorescent probes for detecting G-quadruplexes DNA have bring about an extensive attention in recent years. In this paper, we designed and synthesized three benzothiazole derivatives named 2a-2c under moderate reaction conditions and investigated their interactions with DNA (single-stranded, duplex, i-motif and G-quadruplex) and distribution in living cell. Three compounds present a large Stokes shift (～90 nm) and a weak red fluorescence emission, and they exhibit a good selectivity and sensitive turn-on fluorescence response for the promoter G-quadruplex DNA (bcl-2, c-myc and c-kit 2) and mitochondria G-quadruplex (KSS). The affinity of 2a and 2b with N-alkyl side chain group to DNA is stronger than that of 2c with an anion group, therefore, they also increase the stability of the G-quadruplex structure. 2b induces the conformational change of both bcl-2 and KSS G-quadruplexes, while all compounds induce the folding of bcl-2 from the coiled structure to the hybrid G-qrudruplex. Three compounds interact with the G-quadruplex DNA mainly by end-stacking mode. Furthermore, MTT assays and confocal fluorescence images show that these compounds can enter the living HepG2 cells with low cytotoxicity. 2a-2c are mainly located in the mitochondrion and interacted with mitochondria G-quadruplex DNA, while only weak fluorescence can be found in cell nucleus. In a word, 2a-2c can be implied in image of G-quadruplex DNA in living cells.

The epidemic of multidrug resistance (MDR) is a serious threat to public health, and new classes of antibiotics with novel mechanisms of action are in critical need. We rationally designed and efficiently synthesized three series of new chemical entities with potential antibacterial activity targeting filamenting temperature-sensitive mutant Z (FtsZ). Evaluation of these compounds against a panel of Gram-positive bacteria including MDR and vancomycin-resistant Enterococcus?strains indicated that most compounds showed enhanced antibacterial efficacy, comparable or even superior to the reference drugs. The newly synthesized compounds proved to be substrates of the Escherichia coli efflux pump AcrB, thus affecting the activity. Their structure–activity relationships?were summarized in detail. The most potent compound 10f quickly eliminated bacteria in a bactericidal mode, with low susceptibility to induce bacterial resistance. Further mechanistic studies with the BsFtsZ protein revealed that 10f functioned as an effective FtsZ inhibitor through altering the dynamics of FtsZ self-polymerization via a stimulatory mechanism, which leads to inhibition of cell division and cell death. Besides, 10f not only displayed no obvious cytotoxicity to mammalian cells but also had a high efficacy in a murine model of bacteremia in vivo. Regarded as a whole, our findings highlight 10f as a promising new FtsZ-targeting bactericidal agent.

Alzheimer’s disease (AD) is a neurodegenerative disease, and β-amyloid (Aβ) is believed to be a causative factor in AD pathology. The abnormal deposition of Aβ is believed to be responsible for progression of AD. In order to facilitate the imaging of Aβin vivo, suitable probe molecules with a near-infrared emission wavelength that can penetrate the blood-brain barrier (BBB) were utilized. The commercial fluorescent probe thioflavin-T (ThT) is used to image Aβ; however, because of its short emission wavelength and poor BBB penetration, ThT can only be usedin vitro. With this research, based on ThT, we design three fluorescent probes (SZIs) having a longer emission wavelength in order to image Aβ aggregates. SZIs with different numbers of double bonds respond to Aβ aggregates. The SZIs have a structure similar to ThT, and as such, the SZIs are also unable to penetrate the BBB. To deal with the problem, we develop nanocomposites (MSN-Lf@SZIs) to deliver SZIs into the brain of AD mouse and image Aβ successfully. These new nanocomposites are able to deliver the dyes into the brain and facilitate Aβ imagingin vivo.

The invention discloses a pH sensitive fluorescent probe capable of simultaneously imaging cell nucleuses and mitochondria in two colors. The chemical name of the pH sensitive fluorescent probe is (E)-2-(4-hydroxy-3, 5-dimethoxystyryl)-3-methylbenzothiazo

The formation of biofilms by clinical pathogens typically leads to chronic and recurring antibiotic-resistant infections. High cellular levels of cyclic diguanylate (c-di-GMP), a ubiquitous secondary messenger of bacteria, have been proven to be associate

The unbalanced metabolism of sulfur dioxide can cause various diseases, such as neurological disorders and lung cancer. Until now, some researches revealed that the normal function of lysosomes would be disrupted by its abnormal viscosity. As a signal molecule, sulfur dioxide (SO2) plays an important role in lysosome metabolism. However, the connection of metabolism between the SO2 and viscosity in lysosomes is still unknown. Herein, we developed a benzothiazole-based near-infrared (NIR) fluorescent probe (Triph-SZ), which can monitor the SO2 derivatives and respond to the change of viscosity in lysosomes through two-photon imaging. Triph-SZ present high sensitivity and selectivity fluorescence response with the addition of SO2 derivatives based on the nucleophilic addition, and it also exhibits a sensitive fluorescence enhancement to environmental viscosity, which allows Triph-SZ to be employed to monitor the level of HSO3? and viscosity changes in lysosomes by the two-photon fluorescence lifetime imaging microscopy.

Merocyanine (MC) dyes containing an aromatic donor vinyl linked to a cationic acceptor serve as chemosensors for analyte detection. Their electrophilicity permits anion detection through addition reactions that disrupt dye conjugation. Herein, we demonstr

The present disclosure is in the field of pharmaceutical and chemical sciences, including the synthesis of theranostic agents and processes for preparing such agents. In particular, the disclosure relates to important phenanthroline, carbazole and flavylium based cyanine group containing chemical compounds, method of preparing such molecules and compositions thereof, and the use of such molecules and compositions as a probe and diagnostic agent in the diagnosis and treatment of diseases including cancer.

The invention discloses a fluorescent probe, a preparation method thereof and an application of the fluorescent probe for detecting a nucleic acid G-quadruplex structure. The probe is provided with a structure in a general formula (I) is simple and stable in structure and easy to prepare. The probe can be used for specific detection of a nucleic acid G-quadruplex secondary structure, and the G-quadruplex secondary structure in solution can be rapidly detected by a fluorescence spectrometer or direct visual inspection under irradiation of a fluorescent lamp. The probe can be used for detecting the nucleic acid G-quadruplex structure in agarose gel or polyacrylamide gel and can also be used for detecting, marking or displaying existence or distribution of the G-quadruplex structure in living cells. Fluorescent materials have efficient and specific recognition capability for the nucleic acid G-quadruplex structure, have the advantages of excellent cell membrane permeability, low photo-induced toxicity, biological toxicity and photo-bleaching performance and the like, and overcome the shortcomings of high cost, high equipment requirement, complicated technical operation and the like in other detection methods.

N-Benzyl aroyl-S,N-ketene acetals can be readily synthesized by condensation of aroyl chlorides and N-benzyl 2-methyl benzothiazolium salts in good to excellent yields, yielding a library of 35 chromophores with bright solid-state emission and aggregation

The invention discloses a fluorescent probe for simultaneously detecting DNA and RNA in cells under double channels as well as a preparation method and application of the fluorescent probe. The structure of the fluorescent probe is shown as a formula (I) or (II), wherein the Ar is an aromatic ring or an aromatic heterocyclic ring; the R1 and R2 are respectively and independently hydrogen, N-piperazine, N-methyl piperazine, -NH(CH2)nR3 and -NR3R4; the n is any integer from 1 to 5, and R3 and R4 are respectively and independently hydrogen, C1-C5 alkyl or C1-C5 haloalkyl; the A- is halide ions orp-toluenesulfonic acid ions. The fluorescent probe disclosed by the invention can be used for simultaneously detecting DNA and RNA in vitro and in cells under double channels; meanwhile, the fluorescent probe has the characteristics of rapid synthesis, near-infrared emission wavelength, good light stability, high detection sensitivity and the like, and is convenient to popularize and apply.

The invention provides a benzothiazole derivative and a synthesis method and application thereof. The Chinese name of the derivative is called as (E)-2-(3-(benzo[d]thiazole-2-yl)-2-hydroxy-5-methylstyryl)-3-methylbenzo[d]thiazole-3-iodide, and the structu

Two molecular rotors with a single excitation and dual-color emission wavelengths were engineered for simultaneous imaging of lysosomal and mitochondrial viscosity. These two molecular rotors were highly sensitive to viscosity without dependence on pH or polarity, facilitating simultaneous imaging of lysosomal and mitochondrial viscosity during mitophagy in living cells.

Encrypted markers that are not readily detectable can be revealed by treatment with a specific reagent used as a developer to reveal a readily detectable physical property of the marker, such as a characteristic fluorescence emission after excitation with

In this study, eighteen heptamethine dyes were synthesised and their antifungal activities were evaluated against three clinically relevant yeast species. The eighteen dyes were placed within classes based on their core subunit i.e. 2,3,3-trimethylindolenine (5a-f), 1,1,2-trimethyl-1H-benzo[e]indole (6a-f), or 2-methylbenzothiazole (7a-f). The results presented herein imply that the three families of cyanine dyes, in particular compounds 5a-f, show high potential as selective scaffolds to treat C. albicans infections. This opens up the opportunity for further optimisation and investigation of this class compounds for potential antifungal treatment.

The invention belongs to the medical field and discloses benzothiazole compounds as well as a preparation method and an application thereof. The benzothiazole compounds have the structural formula shown in formula I, wherein Ar is substituted benzene ring

The invention belongs to the technical field of chemical and compound medicines and in particular relates to a thiazole orange benzyl quaternary ammonium salt derivative as well as a preparation method and application thereof. The thiazole orange benzyl quaternary ammonium salt derivative is a compound of a formula I shown in the specification, or a pharmaceutically acceptable salt of the compound, and the compound of the formula I shown in the specification or a solvent compound, an enantiomer, a diastereoisomer, a tautomer or a mixture of the components of any ratio, of a pharmaceutically acceptable salt of the compound, and comprises a racemic mixture; the compound is prepared through condensation of a thiazole orange analog with aromatic aldehyde, and further through a substitution reaction of the thiazole orange analog with a benzyl analog, the preparation method is simple, and the raw materials are easy to obtain; and thiazole has no actions on Fts, after quaternary ammonium formation, thiazole has a Fts action capability and has the capability of prolonging morphologies of bacteria, and verification shows that the thiazole orange benzyl quaternary ammonium salt derivative has good antibacterial and sterilization activity upon escherichia coli and staphylococcus aureus.

The comprehensive understanding of the mechanisms underlying the interaction of cells with their membrane microenvironment is of great value for fundamental biological research; however, tracking biomolecules on cell surfaces with high temporal and spatial resolution remains a challenge. Herein, a modular strategy is presented for the construction of cell surface DNA-based sensors by engineering DNA motifs and synthetic cofactors. In this strategy, a stimuli-reactive organic molecule is employed as the cofactor for the DNA motif, and the self-assembly of them forms a FRET-based holo DNA-based sensor. With the use of the DNA-based sensors, the versatility of this modular strategy has been demonstrated in the ratiometric imaging of the cellular extrusion process of endogenous signaling molecules, including sulfur dioxide derivatives and nitric oxide.

A colorimetric fluorescent probe with fluorescence emission feature sensitive to SO2 derivatives, i.e. bisulfite (HSO3 ?) and sulfite (SO3 2?), was developed based on the HSO3 ?/SO3 2?-mediated nucleophilic addition reaction of the probe that. This probe exhibited SO3 2? sensing ability with detection limit down to 46?nM and desired selectivity over other reference anions and redox species. The preliminary fluorescence bioimaging experiments have validated the practicability of the as-prepared probe for SO2 derivatives sensing in living cells.

The invention discloses azido indol dimethine cyanine dye molecule and application. The azido indol dimethine cyanine dye is characterized in that indol dimethine cyanine dye is treated as a core framework; a side chain containing ester bond and azido ground is introduced into the nitrogen atom of indol. The azido indol dimethine cyanine dye has cell membrane permeability and can be applied to protein detection, vital cell staining, and determining of bacteria living state based on activity of esterase in bacteria; the amplification of dead bacteria in reaction is selectively inhibited, therefore, the purpose of quickly quantitatively detecting living bacteria can be achieved. The dye molecule has a good application prospect in the living bacteria detection.

Due to its remarkable structural and optical stability in biological milieu, a newly developed small molecule based DNA marker with high brightness (Φ = 0.51, brightness = 26?300 M?1 cm?1) and almost zero toxicity has been explored. For the first time to our knowledge, this approach has provided real-time monitoring of growth and reproductive potency of living cells beyond nine days.

The invention discloses a fluorescent probe with water solubility and aggregation-induced emission effects, a nanoparticle, a preparation method and application. The fluorescent probe has structural characteristics of a polyphenyl substituted imidazole ring and quaternary ammonium salt, high dispersity in water and the characteristics of aggregation-induced emission effects, large emission wavelength and the like, and is adapted to fluorescent detection. The fluorescent probe is self-assembled to aggregate and generate red fluorescence under the induction of heparin, and the content of the heparin is reflected to realize quantitative detection of the heparin by detecting the intensity of emitted light, so that the fluorescent probe has the advantages of high sensitivity, high anti-interference performance, and is particularly applied to detection of heparin in an environment such as a chemical solution system and a biological sample. The method has high practical value for detecting trace heparin, monitoring heparin in the blood of a patient in real time and guiding clinical medication.

The invention relates to a two-photon RNA (Ribonucleic Acid) fluorescent probe and application thereof in living cell imaging. A structural general formula is shown as (I), wherein R is alkyl, hydroxyalkyl or ether radical; X is bromine or iodine. The two-photon RNA fluorescent probe is a novel RNA selectively-recognizable two-photon fluorescent probe and can be applied to mark or display application of RNA in living cell distribution. The probe has the characteristics of good membrane permeability, low cell toxicity and high color rendering property, and can be developed into a biological detection reagent for RNA-related physiological and pathological studies.

Near-infrared (NIR) fluorescent probes are advantageous over visible ones, for they can avoid the interference from the short-wavelength background emission in biological systems. However, there are a very limited number of NIR probes that can specifically label target proteins in living cells. In this work, a series of long-wavelength dyes (N-NIR, S-NIR, and K-NIR) analogous to the novel Changsha NIR family are synthesized conveniently through a new approach that is different from the previously reported one. These three dyes have similar conjugation structures but exhibit tunable photophysical properties. N-NIR and S-NIR have large extinction coefficients over 100000, and high fluorescence quantum yields. Although NIR absorption and emission of K-NIR are inferior to the former two, it emits in a much longer wavelength region. And all the three dyes can easily pass through the cell membranes to obtain the high-resolution NIR fluorescence images. Furthermore, N-NIR is chosen as the NIR fluorophore to develop a protein-labeling reagent PYBG-D, since it demonstrates the highest fluorescence quantum yield of up to 0.4 (in methanol). PYBG-D is efficiently synthesized through Sonogashira coupling between bromo-substituted N-NIR and alkyne-substituted benzylguanine (PYBG). The conjugate PYBG-D proves to be a specific and efficient label for O6-alkylguanine-DNA alkyltransferase (SNAP-tag) that fused to target proteins in living cells, which contributes to high resolution NIR fluorescence images under a laser confocal microscope.

The present invention provides dyes having improved characteristics for imaging applications, biosensors comprising such dyes, and methods of use thereof, including methods for detecting target molecules in a sample and for live-cell imaging. The biosensors can include a binding member, including a biomolecule or fragments thereof, which can interact with target molecules of interest and can be specific to a given conformational state or covalent modification of the target molecule. The presently disclosed dyes can be used for detecting changes in the binding, conformational change, or posttranslational modification of the target molecule.

A new RNA-selective fluorescent dye integrated with a thiazole orange and a p-(methylthio)styryl moiety shows better nucleolus RNA staining and imaging performance in live cells than the commercial stains. It also exhibits excellent photostability, cell t

A series of novel photochromic cationic stilbenes dyes bearing different aromatic systems were easily synthesized from (hetero)aromatic aldehydes. The photoisomerization of the double bond can be achieved through irradiation with ultraviolet or visible light, for few seconds, leading to the Z isomers that return much faster to the initial state than common stilbenes. Benzothiazolium dyes with electron donating substituents exhibited very fast thermal back reactions (1 s). Pyrrole-benzothiazolium dye showed a higher lifetime of the Z isomer, in different solvents, including water (0.45-7.1 min). This cationic diarylethene can be switched between the E-Z states using visible light, in few minutes at room temperature, with a noticeable change in the visible spectrum.

Multimodal imaging provides complimentary information that is advantageous in studying both cellular and molecular mechanisms in vivo, which has tremendous potential in pre-clinical research and clinical translational imaging. It is desirable to design probes for multimodal imaging that can be administered minimally but provides multifaceted information. Herein, we demonstrate the complementary dual functional ability of a nanoconstruct for molecular imaging in both photoacoustic (PA) and surface-enhanced Raman scattering (SERS) biosensing simultaneously in tandem. To realize this, a group of NIR active organic molecules are designed and synthesized that possess both SERS and PA activity. Nanoconstructs realized by anchoring such molecules onto gold nanoparticles are demonstrated for targeting cancer biomarkers in vivo while providing complimentary information about biodistribution and targeting efficiency. In future, such nanoconstructs could play a major role in identifying surgical margins and also for disease monitoring in translational medicine. A group of NIR active organic molecules are designed and synthesized that possess both surface-enhanced Raman scattering (SERS) and photoacoustic (PA) activity simultaneously. The complementary dual functional ability of the nanoconstruct realized by anchoring such molecules onto gold nanoparticles is used for the targeted detection and imaging of cancer biomarker and also for a biodistribution study using PA imaging and SERS biosensing in tandem.

The present disclosure relates to compounds which function as small molecule fluorescent probes which aid in recognition of specific sequences in DNA and detection of Αβ aggregates. Probes/dyes of the instant disclosure are specific to AT-rich sequences of DNA and Αβ aggregates. These small organic dyes/probes are capable of exhibiting switch-on fluorescence and play an important role in fluorescence spectroscopy, diagnostics, imaging and biomedical applications.

A series of benzothiazole heptamethine cyanine dyes have been synthesized and their photophysical properties evaluated in relation to their structural features. These have been compared against two classical probes of this type: Indocyanine Green (IGC) and New Indocyanine Green (IR-820). Growth inhibitory studies were also performed using a eukaryotic, unicellular organism, fission yeast Schizosaccharomyces pombe. Herein we highlight some potentially interesting candidates with improved fluorescence quantum yields when compared with ICG and IR-820.

A series of dimethine cyanine dyes, used as fluorescent probes, were synthesized under microwave irradiation, and identified by 1H NMR, IR, elemental analysis and HRMS. The investigation of their spectral properties in phosphate-buffer saline (PBS) showed that the absorption and emission maxima of the dyes were in the region 370-480 nm and 471-569 nm, respectively. The properties of the dyes as fluorescent probes for living cells imaging and flow cytometry were investigated. The results showed that dyes 1, 2, 8 or 9 could penetrate an intact cell membrane, stained the cell nuclear and exhibited bright fluorescence. Little background interference, low cell cytotoxicity and little photobleaching were showed during the imaging tests. The dyes 1, 8 and 9 could be applied in flow cytometry and dye 1/PI, dye 8/PI or dye 9/PI couple could be proposed as double staining agents to measure sperm cell viability. Thus the dyes represented the cell-permeant fluorescent probes.

A chlorinated coumarin-hemicyanine dye with three potential reaction sites was exploited as fluorescent probe for biothiols. The Cys-induced substitution-rearrangement-cyclization, Hcy-induced substitution-rearrangement, and GSH-induced substitution-cycli

The synthesis of a variety of N-alkylated 2,3,3-trimethylindolenines and 2-methylbenzothiazoles is reported herein. Their potential as antifungal agents is evaluated by preliminary screening against Saccharomyces cerevisiae (S. cerevisiae), Schizosaccharomyces pombe (S. pombe), and Candida albicans (C. albicans). Statistical analyses illustrate a strong relationship between chain length and growth inhibition for S. cerevisiae and S. pombe (p 0.0001 in every case). Of particular interest is the activity of both sets of compounds against S. cerevisiae, as this is emerging as an opportunistic pathogen, especially in immunosuppressed and immunocompromised patients. Bioassays were set up to compare the efficacy of our range of N-alkylated compounds against classic antifungal agents; Amphotericin B and Thiabendazole.

The present invention relates to a process for the production of certain compounds, especially dye compounds defined in general by Formula I: The invention provides a one-step method in which a compound of Formula II or a reactive intermediate derived in situ therefrom is reacted in situ with a compound of Formula III (optionally in the presence of a compound of Formula IV) to produce compounds of Formula I in excellent yield, and in a manner which avoids undesirable by- product formation.

A series of unsymmetric pentamethine cyanine dyes featuring benzoxazolyl and benzothiazolyl groups were synthesized, the structures were characterized by 1H NMR, UV-vis absorption spectroscopy and mass spectrometry. The dyes with different anions such as chloride, tetraphenylborate and tetra(4-fluorophenyl)borate were also obtained and their solubility can be changed by the choice of the anion part. The third-order nonlinear optical properties were measured by the Z-scan technique with a picosecond laser beam at 532 nm in DMF solution. The third-order nonlinear optical susceptibilities χ(3) and the second-order hyperpolarizabilities γ' were obtained. The results reveal that these dyes exhibit strong reverse saturable absorption and nonlinear refraction.

Six symmetrical and unsymmetrical trimethine cyanine dyes bearing benzothiazolyl and benzoxazolyl groups were synthesized. Their linear optical properties were studied. It was found that the variation of hetero atoms play an important role in the spectral properties of the dyes. Sequential replacement of the oxygen atom by the sulfur atom resulted in a change in shade from yellow to purple. In order to understand the relationship between the molecular structures and the spectral properties of these dyes, theoretical calculations were made using the Gaussian programme. Key parameters related to absorption and emission spectra were reported and discussed.

Two rhodanine complex merocyanine dyes 9a and 9b were synthesized and their structures were confirmed by 1H NMR, IR, MS, HRMS and UV-Vis spectra. From the spectral properties of the two dyes, it could be found that the λmax of the dyes showed hypsochromic shifts with the increase of permittivity in protonic solvents, and bathochromic shifts with the increase of refractive index in non protonic solvents. The interactions of two dyes with DNA or BSA were also studied under physiological conditions. The results showed that the quantum yield of DNA-dye 9a was up to 29.5 times compared with free dye 9a. Dyes 9a and 9b were researched in Photodynamic Therapy (PDT) as well. It was demonstrated that supplementation of dye 9a or 9b as photosensitizers for PDT in K562 cells decreases the survival rate.

The rapid and convenient method for identification of all kinds of G-quadruplex is highly desirable. In the present study, a novel colorimetric indicator for a vast variety of G-quadruplex was designed and synthesized on the basis of thiazole orange and isaindigotone skeleton. Its distinct color change enables label-free visual detection of G-quadruplexes, which is due to the disassembly of dye H-aggregates to monomers. This specific detection of G-quadruplex arises from its end-stacking interaction with G-quartet. On the basis of this universal indicator, a facile approach for large-scale identification of G-quadruplex was developed.