High-yield synthesis of monodisperse gold nanorods with a tunable plasmon wavelength using 3-aminophenol as the reducing agent.

Facile synthesis of high quality gold nanorods (AuNRs) with a tunable size is of great value for applications of AuNRs in various fields and for the study of the growth mechanism of such anisotropic nanostructures. However, limitations usually exist in a specific synthetic protocol. In this work, using 3-aminophenol as the reducing agent, we present a AuNR synthetic strategy with an excellent comprehensive performance, which includes an exceptional monodispersity, a AuNR shape purity of around 99%, a conversion ratio of the gold precursor of about 91%, and an easily tuned longitudinal surface plasmon resonance wavelength ranging from 580 to ∼1050 nm. Studies on the impacts of the experimental parameters including silver ions, gold seeds, reducing agent, and cetyltrimethylammonium bromide (CTAB) revealed a profound recognition of the significant effect of the reductive atmosphere, in synergy with other parameters, in directing the growth and structural evolution of the gold seeds, thus deeply affecting the size, shape yield, monodispersity, and morphology of the final structure. These results could be immensely useful for the application and revelation of the growth mechanism of AuNRs.

Palladium-Catalyzed C-H Bond Functionalization Reactions Using Phosphate/Sulfonate Hypervalent Iodine Reagents.

A new and operationally simple approach for palladium-catalyzed C-H functionalization reactions utilizing an organophosphorus/sulfonate hypervalent iodine reagent as both an oxidant and the source of a functional group has been developed. Through this method, the oxidative phosphorylation-, sulfonation-, and hydroxylation of unactivated benzyl C(sp3)-H bonds, along with the hydroxylation and arylation of aryl C(sp2)-H bonds, are successfully realized under mild conditions and with excellent site-selectivity. The versatile C-OSO2R bond provides a platform for a wide array of subsequent diversification reactions.

The release of cytochrome c and the regulation of the programmed cell death progress in the endosperm of winter wheat (Triticum aestivum L.) under waterlogging.

It has been shown in mammalian systems that the mitochondria can play a key role in the regulation of apoptosis by releasing intermembrane proteins (such as cytochrome c) into the cytosol. Cytochrome c released from the mitochondria to the cytoplasm activates proteolytic enzyme cascades, leading to specific nuclear DNA degradation and cell death. This pathway is considered to be one of the important regulatory mechanisms of apoptosis. Previous studies have shown that endosperm cell development in wheat undergoes specialized programmed cell death (PCD) and that waterlogging stress accelerates the PCD process; however, little is known regarding the associated molecular mechanism. In this study, changes in mitochondrial structure, the release of cytochrome c, and gene expression were studied in the endosperm cells of the wheat (Triticum aestivum L.) cultivar "huamai 8" during PCD under different waterlogging durations. The results showed that waterlogging aggravated the degradation of mitochondrial structure, increased the mitochondrial permeability transition (MPT), and decreased mitochondrial transmembrane potential (ΔΨm), resulting in the advancement of the endosperm PCD process. In situ localization and western blotting of cytochrome c indicated that with the development of the endosperm cell, cytochrome c was gradually released from the mitochondria to the cytoplasm, and waterlogging stress led to an advancement and increase in the release of cytochrome c. In addition, waterlogging stress resulted in the increased expression of the voltage-dependent anion channel (VDAC) and adenine nucleotide translocator (ANT), suggesting that the mitochondrial permeability transition pore (MPTP) may be involved in endosperm PCD under waterlogging stress. The MPTP inhibitor cyclosporine A effectively suppressed cell death and cytochrome c release during wheat endosperm PCD. Our results indicate that the mitochondria play important roles in the PCD of endosperm cells and that the increase in mitochondrial damage and corresponding release of cytochrome c may be one of the major causes of endosperm PCD advancement under waterlogging.

Room-temperature Cu-catalyzed N-arylation of aliphatic amines in neat water.

A room-temperature and PTC-free copper-catalyzed N-arylation of aliphatic amines in neat water has been developed. Using a combination of CuI and 6,7-dihydroquinolin-8(5H)-one oxime as the catalyst and KOH as the base, a wide range of aliphatic amines are arylated with various aryl and heteroaryl halides to give the corresponding products in up to 95% yield.

Lead adsorption, anticoagulation and in vivo toxicity studies on the new magnetic nanomaterial Fe3O4@SiO2@DMSA as a hemoperfusion adsorbent.

This project aimed to develop and characterize a new nanoadsorbent for hemoperfusion. Fe3O4 nanoparticles synthesized by a facile solvothermal method were coated with SiO2 and further modified by DMSA. TEM, XRD, FTIR, XPS and SEM were performed before and after lead adsorption to reveal the general performance and adsorption mechanism. Rabbit lead poisoning models were established to study the adsorption rate; then, a pig hemoperfusion experiment was used for further validation. In addition, coagulation, liver, kidney and heart function, blood lipids, electrolytes and the immune inflammatory system were studied before and after hemoperfusion. The results indicated that the materials had a high adsorption rate and chemisorbed lead mainly in the plasma. No obvious coagulation-fibrinolysis, organ toxicity, electrolyte disturbances, inflammatory reactions or immunosuppression was observed. The excellent blood compatibility and high biosafety of this material demonstrate its potential as a new type of hemoperfusion adsorbent.

Sulfhydryl-Modified Fe3O4@SiO2 Core/Shell Nanocomposite: Synthesis and Toxicity Assessment in Vitro.

The objectives of this study are to prepare sulfhydryl-modified Fe3O4@SiO2 core/shell magnetic nanocomposites, assess their toxicity in vitro, and explore their potential application in the biomedical fields. Fe3O4 nanoparticles synthesized by facile solvothermal method were coated with SiO2 via the Stöber method and further modified by the meso-2,3-dimercaptosuccinic acid (DMSA) to prepare Fe3O4@SiO2@DMSA nanoparticles. The morphology, structure, functional groups, surface charge, and magnetic susceptibility of the nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, zeta potential analysis, dynamic laser scattering, and vibrating sample magnetometer. Cytotoxicity tests and hemolysis assay were also carried out. Experimental results show that the toxicity of sulfhydryl-modified Fe3O4@SiO2 core/shell nanoparticles in mouse fibroblast (L-929) cell lines is between grade 0 and grade 1, and the material lacks hemolytic activity, indicating good biocompatibility of this Fe3O4@SiO2@DMSA nanocomposite, which is suitable for further application in biochemical fields.

Purification, characterization and biological activities in vitro of polysaccharides extracted from tea seeds.

Three polysaccharide fractions (NTSPS, ATSPS1-1 and ATSPS2) were isolated and purified from the water extract of tea (Camellia sinensis) seeds with yields of 32.74%, 25.22%, and 11.09%, respectively. The average molecular weight of NTSPS, ATSPS1-1 and ATSPS2 was determined by HPGPC system, with an Mw of 4.588, 500 and 100 kDa, respectively. Monosaccharide analysis by ion chromatography revealed they differed from each other in monosaccharide kinds and molar ratio. Furthermore, ATSPS1-1 and ATSPS2 were heteropolysaccharide bounded with protein (2.83% and 2.12%) and 17 general amino acids were detected in them on an ion-chromatographic analyzer. The IR spectrum of ATSPS1-1 and ATSPS2 revealed the typical characteristics of polysaccharides and protein. In addition, the antitumor and immunological activity of the three polysaccharide fractions in vitro were also evaluated. It was found inhibition activity of NTSPS, ATSPS1-1 and ATSPS2 on K562 cells increased with increasing sample concentration and the inhibition ratios of them at 400 µg/mL were beyond 30.13 ± 3.54%, 36.61 ± 2.75% and 32.33 ± 2.53%, respectively. They also exhibited strong ability in promoting proliferation of mice splenic lymphocyte. Results of these studies indicated the three purified polysaccharides had a potential application as natural antitumor drugs.

Investigation of the toxic effect of a QDs heterojunction on the interactions between small molecules and plasma proteins by fluorescence and resonance light-scattering spectra.

The effect of a ZnO#ZnS QDs heterojunction (O#SQDs) on the binding affinities of flavonoid glycosides for bovine serum albumin (BSA) was investigated. The fluorescence intensities of BSA decreased remarkably with increasing concentration of O#SQDs. The magnitudes of the binding constants of flavonoid glycosides for BSA in the presence of O#SQDs were in the range of 10(5)-10(7) L mol(-1), and the number of binding sites per BSA (n) was determined as 1.24 ± 0.17. O#SQDs increased the affinities of flavonoid glycosides for BSA by about 2.96% to 114.68% depending on their structures. O#SQDs in blood will enhance the transportation of flavonoid glycosidegs in blood and improve their pharmacology effects. From this point, O#SQDs are a perfect candidate for flavonoid glycosides delivery applications.

Interaction of dietary polyphenols with bovine milk proteins: molecular structure-affinity relationship and influencing bioactivity aspects.

SCOPE: Dietary flavonoids and stilbenes are important polyphenols in foods, such as, e.g. fruits, vegetables, nuts, and tea as they are of great interest for their bioactivities, which are related to the anti-oxidative property. METHODS AND RESULTS: The relationship between the structural properties of dietary polyphenols and their affinities for milk proteins (MP) was investigated. Methylation and methoxylation of flavonoids decreased (or hardly affected) the affinities for MP. Hydroxylation on the rings A and B of flavones and flavonols enhanced the interaction slightly. The hydroxylation on the ring A of flavanones significantly improved the affinities. Glycosylation of flavonoids weakened the affinities by 1-2 orders of magnitude. The hydrogenation of the C2==C3 double bond of flavonoids decreased the binding affinities by 7.24-75.86-fold. Galloylation of catechins significantly improved the binding affinities by about 100-1000-fold. Glycosylation of resveratrol decreased its affinity for MP. Esterification of gallic acid increased its binding affinity. MP significantly weakened the DPPH radical scavenging activity of polyphenols. The decreasing DPPH scavenging percentages of polyphenols increased with increasing affinities of MP-polyphenol complexes. CONCLUSION: The binding affinities with MP were strongly influenced by the structural differences of dietary polyphenols. The MP-polyphenol interaction weakened with the DPPH free radical scavenging potential of polyphenols.

Composition and bioactivity of polysaccharides from tea seeds obtained by water extraction.

In this paper, the composition and biological activities of polysaccharides from tea seed (TSPS) obtained by water extraction were investigated. The properties and chemical compositions of TSPS were analyzed with HPGPC, IC, and IR methods. The results showed that TSPS consisted of three kinds of polysaccharides with the molecular weight of 500 kDa, 130 kDa, and 5 kDa. TSPS consisted of rhamnose, xylose, arabinose, glucose and galactose, GalA, GulA, with a molar ratio of 4.9:1.7:11.1:27.2:14.0:3.4:1, sugar backbone of TSPS might consist of glucose, but branched chain may consist of rhamnose, xylose, arabinose, and galactose. The IR spectrum of TSPS revealed the typical characteristics of polysaccharides and protein. TSPS significantly inhibited the growth of K562 cells, especially, at the concentration of 50 µg/ml; the inhibition activity of TSPS was the highest with an inhibition ratio beyond 38.44±2.22% (P<0.01). TSPS with high concentrations (100, 200 and 400 µg/ml) had higher proliferation effect on lymphocyte. Results of these studies demonstrated that the polysaccharide had a potential application as natural antitumor drugs.