AND-Logic Based Fluorescent Probe for Selective Detection of Lysosomal Bisulfite in Living Cells.

Sulfur dioxide (SO2) plays significant roles in regulating cell apotosis and inflammation. However, there are complex interactions between small biomolecules in cells, and the identification of these coexisting biomarkers remains a challenge. Herein, we report an AND logic gate based fluorescent probe (NY-Lyso), operating by responding to pH differences between organelles in cell and selectively reacting with bisulfite (HSO3-). This approach allows the fluorescence of the probe to remain silent under neutral or alkaline conditions, notably, is activated by costimulation of lower pH and bisulfite. Furthermore, it was confirmed to be biocompatible and could be employed to monitor HSO3- in lysosomes of living cells. The proposed method demonstrated more practical and outstanding capabilities in targeted and real-time monitoring, providing an effective optical tool for biomarker sensing.

A near-infrared xanthene-based fluorescent probe for selective detection of hydrazine and its application in living cells.

Developing fluorescent probes for selective determination of the toxic and carcinogenic hydrazine are pretty significant. Herein, a rhodamine dye coupled to naphthalene was selected as a near-infrared fluorophore and acetyl group as a trigger unit for hydrazine sensing with a Stokes shifts of 62 nm. The probe showed about 77-fold NIR fluorescence enhancement in the presence of hydrazine. In addition, the detection limit was as low as 3.4 ppb, and the fluorescence intensity at 654 nm showed a satisfactory linearity with the concentration range of hydrazine from 0 to 120 µM. More importantly, the practical utility of probe has been successfully proved through the fluorescence bioimaging of hydrazine in living cells with low cytotoxicity and quantitative N2H4 detection in environmental water samples.

A Redox Stimulation-Activated Amphiphile for Enhanced Photodynamic Therapy.

The development of more efficient photosensitizers with minimal damage to surrounding normal tissues has been a valuable and challenging subject during photodynamic therapy (PDT). Herein, a stimuli-activated porphyrinic photosensitizer (PEG-TPP-DNB; PEG = poly(ethylene glycol); TPP = 5,10,15,20-tetraphenylporphyrin; DNB = 2,4-dinitrobenzene) with capabilities of fluorescence and, remarkably, singlet oxygen quenching was prepared successfully for photodynamic therapy with high efficiency and biosecurity. The amphiphilic PEG-TPP-DNB could be self-assembled into nanomicelles in aqueous media and dissociated in response to reductive thiol such as glutathione. Meanwhile, the fluorescence and singlet oxygen generation of porphyrinic photosensitizer would be activated to regenerate. Moreover, the intracellular uptake and localization effectively confirmed the redox-responsive and activated behavior of PEG-TPP-DNB micelles. The cytotoxicity in vitro revealed that the micelles had low dark toxicity and great phototoxicity, and in vivo bioimaging and antitumor evaluation further indicated that the micelles possessed selective tumor imaging and targeted PDT antitumor effect as well as low systemic toxicity. Overall, this tumor microenvironment-activated photosensitizer system may provide a useful strategy for precise photodynamic therapy.

A colorimetric and turn-on NIR fluorescent probe based on xanthene system for sensitive detection of thiophenol and its application in bioimaging.

Developing fluorescent probes for specific detection of extremely toxic thiophenols is pretty significant in the field of environment, chemistry and biology. We report herein a turn-on red fluorescent xanthene-based probe (RD-Probe) for detecting thiophenol with high selectivity over other analytes including aliphatic thiols. The probe could play the part of a "naked-eye"colorimetric indicator toward thiophenol. Moreover, the relative fluorescence intensity at 653 nm displayed good linearity with the concentration of thiophenol ranging from 0 to 6 µM, and the limit of detection for thiophenol could be as low as 15 nM. Furthermore, the practicability of RD-Probe has been successfully proved through the quantitative thiophenol detection in real water samples and fluorescence bioimaging of thiophenol in HeLa cells.

Reaction-based fluorescent probe for the selective and sensitive detection of thiophenols with a large Stokes shift and its application in water samples.

Although widely used in organic synthesis, pharmaceuticals and agrochemicals, thiophenol has brought about a series of ecological problems due to its high toxicity. Therefore, the development of efficient methods to discriminate thiophenols from aliphatic thiols is of great importance. In this work, a new reaction-based turn-on red fluorescence probe for the detection of thiophenols has been developed for the first time by employing dicyanomethylene-4H-pyran (DCM) as a fluorescence reporter and 2,4-dinitrobenzene-sulfonate (DNBS) as a recognition unit. The probe displayed a highly selective and sensitive (63 fold-fluorescence enhancement) response to thiophenols over aliphatic thiols. Additionally, the probe also exhibited a large Stokes shift (159 nm) and the detection limit reached as low as 8.3 nM. Moreover, this probe was also proved suitable for the quantification of thiophenol in real environmental water samples.

Biomimetic Macroporous PCL Scaffolds for Ex Vivo Expansion of Cord Blood-Derived CD34+ Cells with Feeder Cells Support.

Ex vivo expansion of hematopoietic stem cells (HSCs) with most current methods can hardly satisfy clinical application requirement. While in vivo, HSCs efficiently self-renew in niche where they interact with 3D extracellular matrix and stromal cells. Therefore, co-cultures of CD34+ cells and mesenchyme stem cells derived from human amniotic membrane (hAMSCs) on the basis of biomimetic macroporous three-dimensional (3D) poly(ε-caprolactone) (PCL) scaffolds are developed, where scaffolds and hAMSCs are applied to mimic structural and cellular microenvironment of HSCs. The influence of scaffolds, feeder cells, and contact manners on expansion and stemness maintenance of CD34+ cells is investigated in this protocol. Biomimetic scaffolds-dependent co-cultures of CD34+ cells and hAMSCs can effectively promote the expansion of CD34+ cells; meanwhile, indirect contact is superior to direct contact. The combination of biomimetic scaffolds and hAMSCs represents a new strategy for achieving clinical-scale ex vivo expansion of CD34+ cells.

Higher Order π-Conjugated Polycyclic Hydrocarbons with Open-Shell Singlet Ground State: Nonazethrene versus Nonacene.

Higher order acenes (i.e., acenes longer than pentacene) and extended zethrenes (i.e., zethrenes longer than zethrene) are theoretically predicted to have an open-shell singlet ground state, and the radical character is supposed to increase with extension of molecular size. The increasing radical character makes the synthesis of long zethrenes and acenes very challenging, and so far, the longest reported zethrene and acene derivatives are octazethrene and nonacene, respectively. In addition, there is a lack of fundamental understanding of the differences between these two closely related open-shell singlet systems. In this work, we report the first synthesis of a challenging nonazethrene derivative, HR-NZ, and its full structural and physical characterizations including variable temperature NMR, ESR, SQUID, UV-vis-NIR absorption and electrochemical measurements. Compound HR-NZ has an open-shell singlet ground state with a moderate diradical character (y0 = 0.48 based on UCAM-B3LYP calculation) and a small singlet-triplet gap (ΔES-T = -5.2 kcal/mol based on SQUID data), thus showing magnetic activity at room temperature. It also shows amphoteric redox behavior, with a small electrochemical energy gap (1.33 eV). Its electronic structure and physical properties are compared with those of Anthony's nonacene derivative JA-NA and other zethrene derivatives. A more general comparison between higher order acenes and extended zethrenes was also conducted on the basis of ab initio electronic structure calculations, and it was found that zethrenes and acenes have very different spatial localization of the unpaired electrons. As a result, a faster decrease of singlet-triplet energy gap and a faster increase of radical character with increase of the number of benzenoid rings were observed in zethrene series. Our studies reveal that spatial localization of the frontier molecular orbitals play a very important role on the nature of radical character as well as the excitation energy.

Urethane tetrathiafulvalene derivatives: synthesis, self-assembly and electrochemical properities.

This paper reports the self-assembly of two new tetrathiafulvalene (TTF) derivatives that contain one or two urethane groups. The formation of nanoribbons was evidenced by scanning electron microscopy (SEM) and X-ray diffraction (XRD), which showed that the self-assembly ability of T 1 was better than that of T 2 . The results revealed that more urethane groups in a molecule did not necessarily instigate self-assembly. UV-vis and FTIR spectra were measured to explore noncovalent interactions. The driving forces for self-assembly of TTF derivatives were mainly hydrogen bond interactions and π-π stacking interactions. The electronic conductivity of the T 1 and T 2 films was tested by a four-probe method.

Crystal structure of N-(2-hy-droxy-eth-yl)-5-nitro-isophthalamic acid monohydrate.

In the title compound, C10H10N2O6·H2O, the carb-oxy-lic acid group and the nitro group are essentially coplanar with the benzene ring [maximum deviation = 0.0264 (9) Å], while the amide group is oriented at a dihedral angle of 9.22 (5)° with respect to the benzene ring. In the crystal, classical O-H⋯O and N-H⋯O hydrogen bonds and weak C-H⋯O inter-actions link the organic mol-ecules and water mol-ecules of crystallization into a three-dimensional supra-molecular architecture.

Regioselective chlorination and bromination of unprotected anilines under mild conditions using copper halides in ionic liquids.

By using ionic liquids as solvents, the chlorination or bromination of unprotected anilines at the para-position can be achieved in high yields with copper halides under mild conditions, without the need for potentially hazardous operations such as supplementing oxygen or gaseous HCl.

Large-scale solvent-free chlorination of hydroxy-pyrimidines, -pyridines, -pyrazines and -amides using equimolar POCl3.

Chlorination with equimolar POCl3 can be efficiently achieved not only for hydroxypyrimidines, but also for many other substrates such as 2-hydroxy-pyridines, -quinoxalines, or even -amides. The procedure is solvent-free and involves heating in a sealed reactor at high temperatures using one equivalent of pyridine as base. It is suitable for large scale (multigram) batch preparations.

Methyl 3-carboxy-5-nitrobenzoate.

The structure of the title compound, C(9)H(7)NO(6), is essentially planar [maximum deviation 0.284 (2)Å] except for the methyl H atoms. The crystal structure is stabilized by asymmetric O-H⋯O hydrogen bonds linking the hydrogen carboxyl-ates into pairs around the inversion centres. There is also π-π stacking of the benzene rings [centroid-centroid distance 3.6912 (12) Å].

Separation and purification of verticine and verticinone from Bulbus Fritillariae Thunbergii by high-speed counter-current chromatography coupled with evaporative light scattering detection.

High-speed counter-current chromatography (HSCCC) coupled with evaporative light scattering detection (ELSD) was successfully applied to preparative separation and purification of verticine and verticinone from crude extracts of Bulbus Fritillariae Thunbergii by a one-step separation, using chloroform-ethanol-0.2mol L(-1) hydrochloric acid (3:2:2, v/v/v) as a solvent system. HPLC analysis of the fractions collected on the preparative HSCCC of 200mg of crude extracts showed that the purity of verticine (25.6mg) was 96.8% and that of verticinone (10.3mg) was 95.4%. The chemical identities of these components were confirmed by (1)H NMR and EI-MS.

Characteristics of bicalutamide solid dispersions and improvement of the dissolution.

The purpose of our study was to formulate and evaluate bicalutamide (BL) solid dispersions (SD). The physicochemical properties were evaluated by differential scanning calorimetry (DSC), Fourier-Transform infrared (FT-IR) spectroscopy, Powder X-ray diffractometry (PXRD), dissolution studies, and stability studies. The dissolution studies demonstrated that the dissolution of BL from BL-SD increased with an increase in carrier content (PVP K30). X-ray assays and DSC results both confirmed the amorphous state of BL in BL-SD. Stability studies conducted after 6 months showed that BL exhibited excellent stability in the solid dispersion of PVP K30 (1:5).

HPLC determination of anethole trithione and its application to pharmacokinetics in rabbits.

To evaluate the relative bioavailability of anethole trithione (ATT) from self-microemulsifying drug delivery system (SMEDDS) and tablet, a sensitive, accurate and reliable liquid chromatography method was developed and validated to determine ATT in rabbit plasma. Chromatographic separation was performed on a Diamonsil C18 column by using a mixture of methanol-water (90:10, v/v) delivered at a flow rate of 1.0 ml/min. The wavelength was set at 348 nm and mifepristone was used as the internal standard. A linear relationship for ATT was found in the range of 0.5-32 ng/ml. The mean extraction recoveries of ATT determined over three concentrations were 84.7+/-5.8, 92.3+/-3.4 and 89.9+/-5.1%. After administration of SMEDDS and tablets to rabbits, significant differences were found in main pharmacokinetic parameters of Tmax, Cmax and AUC(0-infinity) between these two formulations, and a 2.5-fold enhancement of relative bioavailability of ATT was observed from the SMEDDS compared with tablets.

Determination of nelfinavir mesylate as bulk drug and in pharmaceutical dosage form by stability indicating HPLC.

A isocratic, selective, accurate and stability indicating HPLC method of analysis of nelfinavir mesylate both as a bulk drug and in formulations was developed and validated. A CN chromatographic column (250 mmx4.6 mm, 5 microm) was used for the separation at 40 degrees C. The mobile phase consisted of a mixture of acetonitrile (MeCN) and 25 mM monobasic ammonium phosphate (containing 25 mM triethylamine, pH 3.4 with phosphate acid) (40:60, v/v) was delivered at a flow rate of 1.0 ml/min with detection at 210 nm. The developed method was validated in terms of selectivity, linearity, limit of quantitation, precision, accuracy and solution stability. As the proposed LC method achieved satisfactory resolution between nelfinavir mesylate, its degradation products, intermediate product possibly present in nelfinavir drug substance and other impurities in the end product before refining in the final step of synthetic process, it can be employed as a stability indicating one, used for the synthetic process control and determination of nelfinavir mesylate in pharmaceutical preparations.

Quantitative determination of puerarin in dog plasma by HPLC and study on the relative bioavailability of sustained release tablets.

To evaluate the bioavailability of puerarin sustained release tablet (SR-Tab.) and Yufengningxin tablet (YU-Tab.), a liquid chromatography method was developed and validated to determine puerarin in dog plasma. Chromatographic separation was performed on Diamonsil C18 column using a mixture of methanol-acetic acid-water (25:6:69, v/v/v) delivered at a flow rate of 1.0 ml/min and detected by UV. 4-Hydroxybenzaldehyde was used as the internal standard. The linear range for puerarin was from 60 to 1800 ng/ml (r=0.9991) with a limit of quantitation of 60 ng/ml. Within-day accuracy and precision ranged from -3.0 to 2.2% and from 1.2 to 4.3%, between-day accuracy and precision ranged from -4.1 to 2.6% and from 1.3 to 5.7%, respectively. The mean extraction recoveries of puerarin determined over the three concentrations were (90.3+/-5.2)%, (95.7+/-1.4)% and (93.1+/-3.5)%. A significant difference was observed in main pharmacokinetic parameters of Tmax, Cmax and AUC0-infinity between puerarin SR-Tab. and YU-Tab. in dogs. The smoother plasma concentrations were obtained from SR-Tab. in dogs and the results were as expected.

Preparative separation and purification of deoxyschisandrin and gamma-schisandrin from Schisandra chinensis (Turcz.) Baill by high-speed counter-current chromatography.

High-speed counter-current chromatography (HSCCC) was successfully applied to the preparative separation and purification of deoxyschisandrin and gamma-schisandrin from the crude petroleum ether extracts of Schisandra chinensis (Turcz.) Baill. The optimum solvent system composed of n-hexane-methanol-water (35:30:3, v/v) led to the successful preparation of deoxyschisandrin and gamma-schisandrin. The analysis of HPLC for each peak fraction of preparative HSCCC showed that the purity of deoxyschisandrin (8 mg) was over 98% and gamma-schisandrin (12 mg) was over 96% from 100 mg of the crude petroleum ether extracts in one-step separation.