Bletilla striata carbon dots with alleviating effect of DSS-induced ulcerative colitis.

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) that significantly affected quality of life for patients. In this study, carbon dots based on Bletilla striata (BS-CDs) were synthesized by hydrothermal method and characterized by optical property analysis. In addition, the study measured the potential effect of BS-CDs on colonic histopathology and inflammation in dextran sulfate sodium (DSS)-induced ulcerative colitis. The results suggested that BS-CDs significantly increased colon length, improved colonic histopathology, and reduced the levels of pro-inflammatory cytokines (TNF-α, IL-1ß, and IL-6) in colitis mice. Taken together, BS-CDs alleviate clinical inflammation by blocking pro-inflammatory cytokines which were expected to be a potential agent for the treatment of colitis.

Direct and Sensitive Electrochemical Determination of Total Antioxidant Capacity in Foods Using Nanochannel-Based Enrichment of Redox Probes.

Simple and sensitive determination of total antioxidant capacity (TAC) in food samples is highly desirable. In this work, an electrochemical platform was established based on a silica nanochannel film (SNF)-modified electrode, facilitating fast and highly sensitive analysis of TAC in colored food samples. SNF was grown on low-cost and readily available tin indium oxide (ITO) electrode. Fe3+-phenanthroline complex-Fe(III)(phen)3 was applied as the probe, and underwent chemical reduction to form Fe2+-phenanthroline complex-Fe(II)(phen)3 in the presence of antioxidants. Utilizing an oxidative voltage of +1 V, chronoamperometry was employed to measure the current generated by the electrochemical oxidation of Fe(II)(phen)3, allowing for the assessment of antioxidants. As the negatively charged SNF displayed remarkable enrichment towards positively charged Fe(II)(phen)3, the sensitivity of detection can be significantly improved. When Trolox was employed as the standard antioxidant, the electrochemical sensor demonstrated a linear detection range from 0.01 µM to 1 µM and from 1 µM to 1000 µM, with a limit of detection (LOD) of 3.9 nM. The detection performance is better that that of the conventional colorimetric method with a linear de range from 1 µM to 40 µM. Owing to the anti-interfering ability of nanochannels, direct determination of TAC in colored samples including coffee, tea, and edible oils was realized.

N-Doped Graphene Quantum Dots Confined within Silica Nanochannels for Enhanced Electrochemical Detection of Doxorubicin.

Herein, we describe a fast and highly sensitive electrochemical sensor for doxorubicin (DOX) detection based on the indium tin oxide (ITO) modified with a binary material consisting of vertically-ordered mesoporous silica films (VMSFs) and N-doped graphene quantum dots (NGQDs). VMSFs, with high permeability and efficient molecular transport capacity, is attached to the ITO electrode via a rapid and controllable electrochemical method, which can serve as a solid template for the confinement of numerous NGQDs through facile electrophoresis. By virtue of the excellent charge transfer capacity, π-π and electrostatic preconcentration effects of NGQDs, as well as the electrostatic enrichment ability of VMSF, the presented NGQDs@VMSF/ITO shows amplified electrochemical signal towards DOX with a positive charge, resulting in good analytical performance in terms of a wide linear range (5 nM~0.1 µM and 0.1~1 µM), high sensitivity (30.4 µA µM-1), and a low limit of detection (0.5 nM). Moreover, due to the molecular sieving property of VMSF, the developed NGQDs@VMSF/ITO sensor has good selectivity and works well in human serum and urine samples, with recoveries of 97.0~109%, thus providing a simple and reliable method for the direct electrochemical analysis of DOX without complex sample pretreatment procedures.

Immunosensor with Enhanced Electrochemiluminescence Signal Using Platinum Nanoparticles Confined within Nanochannels for Highly Sensitive Detection of Carcinoembryonic Antigen.

Rapid, highly sensitive, and accurate detection of tumor biomarkers in serum is of great significance in cancer screening, early diagnosis, and postoperative monitoring. In this study, an electrochemiluminescence (ECL) immunosensing platform was constructed by enhancing the ECL signal through in situ growth of platinum nanoparticles (PtNPs) in a nanochannel array, which can achieve highly sensitive detection of the tumor marker carcinoembryonic antigen (CEA). An inexpensive and readily available indium tin oxide (ITO) glass electrode was used as the supporting electrode, and a layer of amino-functionalized vertically ordered mesoporous silica film (NH2-VMSF) was grown on its surface using an electrochemically assisted self-assembly method (EASA). The amino groups within the nanochannels served as anchoring sites for the one-step electrodeposition of PtNPs, taking advantage of the confinement effect of the ultrasmall nanochannels. After the amino groups on the outer surface of NH2-VMSF were derivatized with aldehyde groups, specific recognition antibodies were covalently immobilized followed by blocking nonspecific binding sites to create an immunorecognition interface. The PtNPs, acting as nanocatalysts, catalyzed the generation of reactive oxygen species (ROS) with hydrogen peroxide (H2O2), significantly enhancing the ECL signal of the luminol. The ECL signal exhibited high stability during continuous electrochemical scanning. When the CEA specifically bound to the immunorecognition interface, the resulting immune complexes restricted the diffusion of the ECL emitters and co-reactants towards the electrode, leading to a reduction in the ECL signal. Based on this immune recognition-induced signal-gating effect, the immunosensor enabled ECL detection of CEA with a linear range of 0.1 pg mL-1 to 1000 ng mL-1 with a low limit of detection (LOD, 0.03 pg mL-1). The constructed immunosensor demonstrated excellent selectivity and can achieve CEA detection in serum.

Disposable Amperometric Label-Free Immunosensor on Chitosan-Graphene-Modified Patterned ITO Electrodes for Prostate Specific Antigen.

A facile and highly sensitive determination of prostate-specific antigen (PSA) is of great significance for the early diagnosis, monitoring and prognosis of prostate cancer. In this work, a disposable and label-free electrochemical immunosensing platform was demonstrated based on chitosan-graphene-modified indium tin oxide (ITO) electrode, which enables sensitive amperometric determination of PSA. Chitosan (CS) modified reduced graphene oxide (rGO) nanocomposite (CS-rGO) was easily synthesized by the chemical reduction of graphene oxide (GO) using CS as a dispersant and biofunctionalizing agent. When CS-rGO was modified on the patterned ITO, CS offered high biocompatibility and reactive groups for the immobilization of recognition antibodies and rGO acted as a transduction element and enhancer to improve the electronic conductivity and stability of the CS-rGO composite film. The affinity-based biosensing interface was constructed by covalent immobilization of a specific polyclonal anti-PSA antibody (Ab) on the amino-enriched electrode surface via a facile glutaraldehyde (GA) cross-linking method, which was followed by the use of bovine serum albumin to block the non-specific sites. The immunosensor allowed the detection of PSA in a wide range from 1 to 5 ng mL-1 with a low limit of detection of 0.8 pg mL-1. This sensor also exhibited high selectivity, reproducibility, and good storage stability. The application of the prepared immunosensor was successfully validated by measuring PSA in spiked human serum samples.

Preparation, characterization, and stability of chitosan-tremella polysaccharide layer-by-layer encapsulated astaxanthin nanoemulsion delivery system.

In this study, a layer-by-layer (LBL) encapsulated astaxanthin (Ast) nanoemulsion delivery system based on chitosan (CS) and tremella polysaccharide (TP) was successfully developed. The system constructed an Ast-CS-TP emulsion with high encapsulation efficiency and an excellent stability profile by utilizing the opposite charge properties of CS and TP. This study evaluated the effects of different stresses (including temperature, salt addition, pH, UV irradiation, and centrifugal force) on the emulsion's stability. To further investigate the protective mechanism of the emulsions, we performed antioxidant activity experiments after UV treatment. Additionally, an in vitro digestion experiment was conducted to assess the behavior of Ast emulsion under simulated gastrointestinal conditions. The stability correlation coefficients were calculated using the Python database Pandas. The results showed that Ast-CS-TP emulsions exhibited turbidity and enhanced homogeneity with a small particle size of around 400 nm and a high absolute zeta potential of 35 mV and exhibited excellent stability under various stresses. The Ast-CS-TP emulsions also exhibited pH-responsive release at pH ≥ 7, consistent with pH changes in the gastrointestinal tract, and were stable in highly concentrated salt solutions. We found that the CS and TP layers significantly improved the photostability of Ast. CS and TP significantly enhanced Ast's oral bioavailability. The stability correlation coeffcients showed that pH and salt concentration were the largest factors that affected the stability of the emulsion. This study provided important insights into the encapsulation and targeting of Ast, providing a theoretical foundation and technical guidance for the comprehensive utilization of Ast.

The protection of polysaccharide from the Brown Seaweed Sargassum graminifolium against ethylene glycol-induced mitochondrial damage.

The aim of the present study is to evaluate the protective effect of polysaccharide from the Brown Seaweed Sargassum graminifolium (SGP) on ethylene glycol-induced kidney damage and the mechanism of SGP-mediated protection. Mitochondrial lipid peroxidation, mitochondrial swelling, the activity of succinate dehydrogenase (SDH), ATPases and mitochondrial antioxidant enzymes was observed in hyperoxaluric rats. Administration of SGP (25, 100 and 400 mg·kg-1, intragastrically) increased the activities of antioxidant enzymes, SDH and Na+/K+-ATPases, Ca2+-ATPases, Mg2+-ATPases, also decreased mitochondrial lipid peroxidation and mitochondrial swelling. SGP exhibited a protective effect by improving antioxidant enzymes and restoring mitochondrial dysfunction in the kidney of hyperoxaluric rats. It may be used as a promising therapeutic agent to provide superior renal protection.

Application of portable gas chromatography-photo ionization detector combined with headspace sampling for field analysis of benzene, toluene, ethylbenzene, and xylene in soils.

A method based on headspace (HS) sampling coupling with portable gas chromatography (GC) with photo ionization detector (PID) was developed for rapid determination of benzene, toluene, ethylbenzene, and xylenes (BTEX) in soils. Optimal conditions for HS gas sampling procedure were determined, and the influence of soil organic matter on the recovery of BTEX from soil was investigated using five representative Chinese soils. The results showed that the HS-portable-GC-PID method could be effectively operated at ambient temperature, and the addition of 15 ml of saturated NaCl solution in a 40-ml sampling vial and 60 s of shaking time for sample solution were optimum for the HS gas sampling procedure. The recoveries of each BTEX in soils ranged from 87.2 to 105.1 %, with relative standard deviations varying from 5.3 to 7.8 %. Good linearity was obtained for all BTEX compounds, and the detection limits were in the 0.1 to 0.8 µg kg(-1) range. Soil organic matter was identified as one of the principal elements that affect the HS gas sampling of BTEX in soils. The HS-portable-GC-PID method was successfully applied for field determination of benzene and toluene in soils of a former chemical plant in Jilin City, northeast China. Considering its satisfactory repeatability and reproducibility and particular suitability to be operated in ambient environment, HS sampling coupling with portable GC-PID is, therefore, recommended to be a suitable screening tool for rapid on-site determination of BTEX in soils.

In vitro antioxidant activity of the polysaccharide from Auricularia auricula and its structural characterisation.

A new polysaccharide (AAP) was extracted from Auricularia auricula by water extraction and alcohol precipitation. The antioxidant activity in vitro showed that AAP had a good scavenging effect on ABTS free radicals. Then AAP was purified by DEAE-52 ion exchange chromatography to obtain the purified component pAAP. The structure analysis showed that the molecular weight (Mw) of pAAP was 96.768 kDa, which was composed of rhamnose (Rha), arabinose (Ara), fucose (Fuc), xylose (Xyl), mannose (Man), glucose (Glu) and galactose (Gal), with the ratio of 0.1:0.157:0.33:2.797:2.881:2.988:0.587, and contained α-pyranose configuration and ß-pyranose configuration. Field emission scanning electron microscopy and atomic force microscopy revealed the special conformation of pAAP in the ring and chain shape.

Antioxidant properties of polysaccharide from the brown seaweed Sargassum graminifolium (Turn.), and its effects on calcium oxalate crystallization.

We investigated the effects of polysaccharides from the brown seaweed Sargassum graminifolium (Turn.) (SGP) on calcium oxalate crystallization, and determined its antioxidant activities. To examine the effects of SGP on calcium oxalate crystallization, we monitored nucleation and aggregation of calcium oxalate monohydrate crystals, using trisodium citrate as a positive control. We assessed antioxidant activities of SGP by determining its reducing power, its ability to scavenge superoxide radicals, and its activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The nucleation inhibition ratio of trisodium citrate and SGP was 58.5 and 69.2%, respectively, and crystal aggregation was inhibited by 71.4 and 76.8%, respectively. Increasing concentrations of SGP resulted in increased scavenging of superoxide anions and DPPH radicals (IC50 = 1.9 and 0.6 mg/mL, respectively). These results suggest that SGP could be a candidate for treating urinary stones because of its ability to inhibit calcium oxalate crystallization and its antioxidant properties.

Bis[µ-4-methyl-2-(2-pyridyl-methyl-sulfan-yl)pyrimidine-κN]bis-[(trifluoro-methanesulfonato-κO)silver(I)].

In the centrosymmetric dinuclear title complex, [Ag(2)(CF(3)SO(3))(2)(C(11)H(11)N(3)S)(2)], the Ag(I) atom is coordinated by two N atoms from two 4-methyl-2-(2-pyridyl-methyl-sulfan-yl)pyrimidine ligands and one O atom from a trifluoro-methane-sulfonate anion in a distorted T-type coordination geometry. The ligand adopts a bidentate bridging coordination mode through one pyridyl N atom and one pyrimidine N atom. In the crystal structure, π-π inter-actions are present between adjacent pyrimidine rings, with a centroid-to-centroid distance of 3.875 (7) Å.

Tetra-aqua-bis(3-carboxyl-atopyridine N-oxide-κO)cadmium(II).

In the title complex, [Cd(C(6)H(4)NO(3))(2)(H(2)O)(4)], the Cd(II) atom is situated on a crystallographic centre of inversion. The Cd(II) atom shows a slightly distorted octa-hedral geometry and is coordinated by four O atoms from water mol-ecules and two O atoms from deprotonated carboxyl groups of nicotinic acid N-oxide ligands. The mononuclear complex mol-ecules are linked by O-H⋯O hydrogen bonds, forming a three-dimensional network structure.

A one-dimensional cadmium(II) complex supported by a sulfur-nitro-gen mixed-donor ligand.

In the title compound, catena-poly[cadmium(II)-bis-(µ-5-am-ino-1,3,4-thia-diazole-2-thiol-ato)-κ(2)N(3):S(2);κ(2)S(2):N(3)], [Cd(C(2)H(2)N(3)S(2))(2)](n), the Cd(II) ion is coordinated by two N atoms of the 1,3,4-thia-diazole rings from two ligands and two S atoms of sulfhydryl from two other ligands in a slightly distorted tetra-hedral geometry. The ligands bridge Cd(II) ions, forming one-dimensional chains along [001], which are connected by N-H⋯N and N-H⋯S hydrogen bonds into a three-dimensional network.

2,2'-[o-Phenylenebis(methylenethio)]bis(pyridine N-oxide).

In the title compound, C(18)H(16)N(2)O(2)S(2), the benzene ring makes dihedral angles of 7.41 and 86.59° with the two outer pyridine N-oxygen rings. Two short intramolecular C-H⋯S contacts occur. The crystal packing is stabilized by C-H⋯O hydrogen bonds, C-H⋯π inter-actions and weak π-π staking inter-actions [centroid-centroid distance 3.7596 (7) Å].

Bis(5,6-dicarboxy-benzimidazolium) sulfate monohydrate.

In the title compound, 2C(9)H(7)N(2)O(4) (+)·SO(4) (2-)·H(2)O, the sulfate S atom and the water O atom reside on a crystallographic twofold axis. In the crystal, the component species are linked by N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds, forming a three-dimensional network structure. An intramol-ecular O-H⋯O link is seen in the cation.

Tetra-µ-acetato-bis-[(pyridine N-oxide)copper(II)](Cu-Cu).

The mol-ecule of the title binuclear copper(II) complex, [Cu(2)(CH(3)COO)(4)(C(5)H(5)NO)(2)], occupies a special position on a crystallographic inversion centre; the coordination environment of the Cu(II) atom is slightly distorted square-pyramidal and is made up of four O atoms belonging to four acetate groups in the basal plane with the O atom of pyridine N-oxide ligand in the apical position. The Cu-Cu distance is 2.6376 (6) Å.

2,2'-[Ethane-1,2-diylbis(sulfanedi-yl)]bis-(pyridine N-oxide).

The tile compound, C(12)H(12)N(2)O(2)S(2), lies on an inversion center. The two pyridyl rings are parallel to each other. The structure is devoid of any classical hydrogen bonds due to lack of appropriate donors and acceptors for such bonds. However, non-classical hydrogen bonds of the types C-H⋯O and C-H⋯S stabilize the structure.

Tetra-aqua-hexa-kis(µ(2)-quinoline-4-carboxyl-ato)diyttrium(III) dihydrate.

In the title centrosymmetric binuclear complex, [Y(2)(C(10)H(6)NO(2))(6)(H(2)O)(4)]·2H(2)O, each Y(III) atom is nine-coordin-ated by nine O atoms from five ligands and two water mol-ecules in a slightly distorted monocapped square-anti-prismatic coordination environment. The Y(III) atoms are separated by a distance of 4.0363 (9) Å. The ligands coordinate in three different modes: chelating, bridging and a mixed chelating bridging mode. In the crystal structure, the binuclear complexes are linked by O-H⋯O and O-H⋯N hydrogen bonds, forming a three-dimensional network.

catena-Poly[silver(I)-µ-pyrazolato-κN:N'].

The title compound, [Ag(C(3)H(3)N(2))](n), has an infinite helical chain structure in which each pyrazolate group bridges two Ag(I) atoms related by a 2(1) axis with an intra-chain Ag⋯Ag separation of 3.3718 (7) Å. Each Ag(I) center is linearly coordinated by two N atoms [N-Ag-N angle = 169.98 (14)°]. The chains are held together by inter-chain Ag⋯Ag inter-actions [3.2547 (6) Å], forming a two-dimensional layer. The X-ray single-crystal diffraction result is consonant with that of the ab initio X-ray powder diffraction reported by Masciocchi, Moret, Cairati, Sironi, Ardizzoia & La Monica [J. Am. Chem. Soc. (1994). 116, 7668-7676], with only minor deviations of structural parameters.

Penta-aqua-(1H-benzimidazole-5,6-di-carboxyl-ato-κN)copper(II) penta-hydrate.

The title compound, [Cu(C(9)H(4)N(2)O(4))(H(2)O)(5)]·5H(2)O, contains one crystallographically independent Cu(II) atom and one 1H-benzimidazole-5,6-dicarboxyl-ate (bdc) ligand, along with five coordinated and five uncoordinated water mol-ecules. The Cu(II) atom is six-coordinated by one N atom from the bdc ligand and five O atoms from water mol-ecules, giving an octa-hedral coordination geometry. Hydrogen bonds link the mononuclear complex and uncoordinated water mol-ecules into a three-dimensional network.