A highly sensitive ratiometric fluorescent probe based on fluorescein coumarin for detecting hydrazine in actual water and biological samples.

Hydrazine (N2 H4 ) is a highly toxic and harmful chemical reagent. Fluorescent probes are simple and efficient tools for sensitive monitoring of N2 H4 enrichment in the environment, humans, animals, and plants. In this work, a ratiometric fluorescent probe (FP-1) containing coumarin was used for hydrazine detection. The proposed FP-1 probe had a linear detection range of 0-250 µM and a limit of detection (LOD) of 0.059 µM (1.89 ppb). A large red Stokes shift was observed in fluorescence and UV-vis absorption spectra due to the hydrolysis of ester bonds between FP-1 and hydrazine. The hydrazine detection mechanism of FP-1 was also investigated using density functional theory (DFT) calculations. Finally, FP-1 could sensitively and selectively monitor hydrazine in actual water samples and BEAS-2B cells. Therefore, it has great application potential in environmental monitoring and disease diagnosis.

A novel NIR fluorescent probe for enhanced ß-galactosidase detection and tumor imaging in ovarian cancer models.

The advancement of biological imaging techniques critically depends on the development of novel near-infrared (NIR) fluorescent probes. In this study, we introduce a designed NIR fluorescent probe, NRO-ßgal, which exhibits a unique off-on response mechanism to ß-galactosidase (ß-gal). Emitting a fluorescence peak at a wavelength of 670 nm, NRO-ßgal showcases a significant Stokes shift of 85 nm, which is indicative of its efficient energy transfer and minimized background interference. The probe achieves a remarkably low in vitro detection limit of 0.2 U/L and demonstrates a rapid response within 10 min, thereby underscoring its exceptional sensitivity, selectivity, and operational swiftness. Such superior analytical performance broadens the horizon for its application in intricate biological imaging studies. To validate the practical utility of NRO-ßgal in bio-imaging, we employed ovarian cancer cell and mouse models, where the probe's efficacy in accurately delineating tumor cells was examined. The results affirm NRO-ßgal's capability to provide sharp, high-contrast images of tumor regions, thereby significantly enhancing the precision of surgical tumor resection. Furthermore, the probe's potential for real-time monitoring of enzymatic activity in living tissues underscores its utility as a powerful tool for diagnostics in oncology and beyond.

A novel ICT-based chemosensor for F- and its application in real samples and bioimaging.

A novel colorimetric and fluorescent chemosensor MQS-Si with intramolecular charge transfer character has been designed and synthesized. The chemosensor shows exclusively "off-on" fluorescence response toward F- at 620 nm in HEPES (pH 7.4): DMSO solution (7:3, v/v), which is attributed to the specific cleavage of Si-O bond. The ultrasensitive detection limit for F- in the fluorescence measurement is down to 30 nM. Application of the chemosensor has been demonstrated by selective detection of F- in drinking water, urine and serum samples and fluorescence imaging of F- in living cells and zebrafish, which proves that MQS-Si has a promising application in vitro and in vivo detection of F- and may be utilized for the diagnosis of fluorosis and esteofluorosis.

Improved disc SDS-PAGE for extraction of low molecular weight proteins from serum.

The low molecular weight proteins can provide a lot of valuable information of biomarkers. To study these proteins, the high abundance and high molecular weight proteins must be removed prior to analysis. In this work, a simple and inexpensive disc SDS-PAGE to extract low molecular weight proteins from human serum and cutoff proteins larger than 30 kDa was developed. Some experimental conditions were examined. The experimental results obtained by plate SDS-PAGE and MALDI-TOF MS showed that the molecular weight of extracted proteins was about in the range from 0.3 to 28 kDa. Some experiments, including precipitation of proteins in organic solvents, SPE and cytochrome C test, were carried out and the experimental results demonstrated successful recovery of proteins/peptides with molecular weight from several hundreds of dalton to about 30 kDa. The experimental results obtained by plate SDS-PAGE indicated the repeatability was satisfactory.

catena-Poly[[[aqua-silver(I)]-µ-4,4'-bipyridine-κN:N'] 4-amino-benzoate nitrate hydrate].

In the structure of the title compound, 2[Ag(C(10)H(8)N(2))(H(2)O)](C(7)H(6)NO(2))(NO(3))·H(2)O, the Ag(I) atom is three-coordinated in a T-shaped configuration by two N atoms from two symmetry-related 4,4'-bipyridine (bipy) ligands at short distances and by one water O atom at a longer distance. Each bipy ligand bridges two neighbouring Ag(I) atoms, forming a chain structure extending parallel to [101]. The complete 4-amino-benzoate anion, the nitrate anion and the uncoordinated water mol-ecule are located on mirror planes: together with the coordinated water mol-ecule, they form N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds, stabilizing the crystal structure.

A novel "off-on" rhodamine-based colorimetric and fluorescent chemosensor based on hydrolysis driven by aqueous medium for the detection of Fe3.

A novel "off-on" colorimetric and fluorescent chemosensor N2,N6-bis(2-(rhodamine B amido)ethyl)pyridine-2,6-dicarboxamide (RhBEP) has been designed and synthesized, which can selectively detect the presence of Fe3+ with about 75-fold enhancement in fluorescence emission intensity at 585 nm over various environmentally relevant metal cations such as Hg2+, Cu2+, Cr3+, Li+, Na+, K+, Ag+, Zn2+, Mg2+, Ca2+, Ba2+, Fe2+, Cd2+, Ni2+, Mn2+, Al3+, Bi3+ and Au3+ in PBS reaction media. The remarkable color change from UV-Vis titration experiments indicates that RhBEP can be used as a colorimetric chemosensor for Fe3+. The ultrasensitive detection limit for Fe3+ in the fluorescence measurement is down to 2.0 × 10-8 mol·L-1. The recognition mechanism of RhBEP to Fe3+ was analyzed by Job's plot and mass spectrometry analysis. In addition, the data from fluorescent cell imaging experiments confirmed that the chemosensor RhBEP has a promising application for the detection of Fe3+ in biological systems.

Design of a Nile red-based NIR fluorescent probe for the detection of hydrogen peroxide in living cells.

In this article, a novel fluorescent probe (NRBE) for detecting H2O2 was developed using benzyl boronic ester as the H2O2-recognized group and Nile red as the matrix. The probe has several advantages, such as good selectivity, high sensitivity (LOD = 75 nM), good water solubility and emission in the near-infrared region (ex/em:585/670 nm). With the NRBE probe, the endogenous H2O2 in human hepatocellular carcinoma cells BEL-7402, was detected, and the H2O2 generated during the ischemia-reperfusion of the cells was imaged. These results show that NRBE can be applied for real-time detection of H2O2 in biological systems.

Investigation on hyperin-cetyltrimethylammonium bromide-fibronectin system by resonance light-scattering technique.

A simple, highly sensitive assay for fibronectin (Fn) was reported using resonance light-scattering (RLS) technique based on the enhanced RLS intensity of hyperin-cetyltrimethylammonium bromide (CTMAB)-Fn system. The interaction system of hyperin-CTMAB-Fn was investigated using spectral methods. Mechanistic investigations show that the main reason of the enhanced RLS intensity of Fn is the formation of three-component complex (hyperin-CTMAB-Fn), in which CTMAB acts as a bridge between hyperin and Fn. The effects of pH, surfactant, concentration of CTMAB and hyperin, incubation time and foreign substances on the enhancement of RLS intensity were studied. Under the optimum conditions, the enhancement of RLS intensity is in proportion to the concentration of Fn in the range of 1.9-248ng/ml. The synthetic samples containing Fn were analyzed and results obtained were satisfied.

Aqua-(3-methyl-isoquinoline-κN)silver(I) 4-amino-benzene-sulfonate.

In the title compound, [Ag(C(10)H(9)N)(H(2)O)](C(6)H(6)NO(3)S), the Ag(I) atom is two-coordinated by one N atom from a 3-methyl-isoquinoline ligand and one water mol-ecule. The 4-amino-benzene-sulfonate counter-anion does not show any bonding inter-actions with the Ag(I) atom. The compound exhibits a three-dimensional supra-molecular structure constructed by hydrogen bonds. Adjacent isoquinoline groups form π-π inter-actions, with a centroid-centroid distance of 3.54 (1) Å. The crystal studied was an inversion twin.

Improved solvent-free microwave extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim.

Solvent-free microwave extraction (SFME) is a recently developed green technique which is performed in atmospheric conditions without adding any solvent or water. SFME has already been applied to extraction of essential oil from fresh plant materials or dried materials prior moistened. The essential oil is evaporated by the in situ water in the plant materials. In this paper, it was observed that an improved SFME, in which a kind of microwave absorption solid medium, such as carbonyl iron powders (CIP), was added and mixed with the sample, can be applied to extraction of essential oil from the dried plant materials without any pretreatment. Because the microwave absorption capacity of CIP is much better than that of water, the extraction time while using the improved SFME is no more than 30 min using a microwave power of 85 W. Compared to the conventional SFME, the advantages of improved SFME were to speed up the extraction rate and need no pretreatment. Improved SFME has been compared with conventional SFME, microwave-assisted hydrodistillation (MAHD) and conventional hydrodistillation (HD) for the extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim. By using GC-MS system the compositions of essential oil extracted by applying four kinds of extraction methods were identified. There was no obvious difference in the quality of essential oils obtained by the four kinds of extraction methods.

[Simultaneous determination of total flavone and total saponin in Gynostemma pentaphyllum by signal multiplier spectrophotometry].

Important chemical constituents analysis for the total flavone and total saponin in Gynostemma pentaphyllum is described. The colour reactions of flavones and saponines with vanillin-perchloric acid in acetic acid produced the good absorptions at 451 and 547 nm, but the absorption peaks too overlapped to be determined simultaneously. A new method for the total flavone and the total saponin in Gynostemma pentaphyllum to be determined by signal multiplier spectrophotometry simultaneously without any preliminary separation was proposed. For quantitative analysis, the rutinum as a standard of the total flavone and the ginsenoside Rb1 as standard of the total saponin were applied. The experiment results showed that the regression equations of concentration and deltaA were obtained: deltaAflavone = 0.0133+4.417 0Cflavone, relation coefficient rflavone = 0.9994, and the total flavone concentrations were in 0-0. 16 microg x mI(-1) with deltaA obeying linear relation; deltaAsaporin = 2.775 5Csaponin -0.8881 x 10(-2), relation coefficient rsaponin = 0.9991, and the total saponin concentrations were in 0-0.30 microg x mL(-1) with deltaA obeying linear relation respectively. The recovery ratio was 104.0%-113.0% and 86.8%-94.6% respectively. The RSDflavone was less than 0.58% (n = 9) and RSDsaponin was less than 0. 35% (n=9) respectively. The proposed method is simple, rapid accurate and feasible.

A novel fluorescent probe for Cr(3+) based on rhodamine-crown ether conjugate and its application to drinking water examination and bioimaging.

A trivalent chromium (Cr(3+)) fluorescence probe (RhC) was designed and synthesized via Schiff base reaction based on rhodamine-crown ether conjugate. This probe displayed a favorable selectivity for Cr(3+) over a range of other common metal ions in DMF/H2O (3:7, v/v; PBS buffer 50 mmol L(-1); pH=6.8) solution, leading to prominent fluorescence "OFF-ON" switching of the rhodamine fluorophore. The limit of detection was calculated to be 1.5 µmol L(-1) (S/N=3). The binding ratio of RhC-Cr(3+) complex was determined to be 1:2 according to the Job's plot and HR-MS. The probe was successfully applied to examination of Cr(3+) in drinking water spiked samples. The average recoveries ranged from 104.9% to 106.9% at spiked concentration level of 10.00 µmol L(-1), and the obtained results were consistent with those obtained using atomic absorption spectrometry (AAS). Moreover, bioimaging experiments showed that RhC can sense the Cr(3+) in living cells with a fluorescence enhancement signal.

Rapid analysis of the essential oils from dried Illicium verum Hook. f. and Zingiber officinale Rosc. by improved solvent-free microwave extraction with three types of microwave-absorption medium.

A new method of extracting essential oils from dried plant materials has been studied. By adding a microwave-absorption medium (MAM) to a reactor, solvent-free microwave extraction (SFME) was improved and can be used to extract essential oils from dried plant material without pretreatment. With a microwave irradiation power of 85 W it took only approximately 30 min to extract the essential oils completely. The whole extraction process is simple, rapid, and economical. Three types of MAM, iron carbonyl powder (ICP), graphite powder (GP), and activated carbon powder (ACP), and two types of dried plant material, Illicium verum Hook. f. and Zingiber officinale Rosc., were studied. The results were compared with those obtained by use of conventional SFME, microwave-assisted hydrodistillation (MAHD), and conventional hydrodistillation (HD), and the conclusion drawn was that improved SFME was a feasible means of extracting essential oils from dried plant materials, because there were few differences between the composition of the essential oils extracted by improved SFME and by the other methods.

Analysis of menthol in three traditional Chinese medicinal herbs and their compound formulation by GC-MS.

A GC-MS method was developed for identification and determination of menthol in three traditional Chinese medicinal herbs and their compound formulation, a granule for treating colds. Volatile oil was simultaneously distilled and extracted into ethyl ether in a unique glass extractor. The separation was performed on an HP-5 MS column. The standard addition method was used for quantitative determination of menthol content in herbal materials and in the granule. A component in the samples was chosen as the internal standard. The contents were calculated with the ratio of peak area percentage. Menthol was identified as the main component in Mentha haplocalyx Briq., and also existed in spikes of Schizonepeta tenuifolia Briq., Folium perilla frutescens (L.) Britt. and granules. The quantitative calibration range was 0.21-10.5 mg/mL. Good precision was demonstrated by an RSD < 4.0%. The mean content of menthol in Mentha haplocalyx Briq., spikes of Schizonepeta tenuifolia Briq., Folium perilla frutescens (L.) Britt. and granules was 121, 0.234, 1.03 and 1.84 mg/kg respectively.