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A systematic investigation into the photoluminescence and afterglow mechanisms of trivalent Dy ion doped CaAl2O4.

Multifunctional nanoclusters based on Fe3O4 nanoparticles for magnetic resonance imaging (MRI) and drug delivery are reported here. At first, oleic acid (OA)-coated Fe3O4 nanoparticles were prepared. Then block copolymer Pluronic F127 or folic acid (FA) conjugated-Pluronic F127 was used to modify the hydrophobic nanoparticles to become hydrophilic Fe3O4@F127 nanoclusters via facile ultrasonic treatment. During this process, drug molecules can also be introduced into the nanoclusters and therefore the targeted drug delivery system was formed. Next, we verified the feasibility of the nanoclusters as drug delivery vehicles and magnetic contrast agents. The nanoclusters have an average size of 200 nm and remained stable in water for long periods. Folic acid-modified nanoclusters showed an enhanced intracellular uptake into HepG2 cells by using both cellular iron amount analysis and flow cytometry analysis. Besides, Fe3O4@F127@FA nanoclusters showed good compatibility in the tested concentration range and good sensitivity in T2-weighted MRI. The magnetic nanoclusters combined with drug delivery properties have greatly increased the significance in the diagnosis and therapy of diseases, which are suitable for systematical administration of hydrophobic drugs and simultaneously MRI diagnosis.

An ultra-sensitive T2-weighted MR imaging contrast agent was prepared based on Fe3O4 nanoparticles and Gd3+ ions (Fe3O4@Gd). Amino modified Fe3O4 nanoparticles were conjugated to diethylenetriamine pentaacetic acid, and finally coordinated with Gd3+ ions. The nanoparticles had a uniform morphology with a size of 100 nm and a Gd/Fe mass ratio of 1/110. The r2 (transverse relaxivity) of the Fe3O4 nanoparticles increased from 131.89 mM−1 s−1 to 202.06 mM−1 s−1 after coordination with Gd3+ ions. MR measurements showed that the aqueous dispersion of Fe3O4@Gd nanoparticles had an obvious concentration-dependent negative contrast enhancement. Hepatoma cells were selected to test the cytotoxicity and MR imaging effect. The application of Fe3O4@Gd nanoparticles as contrast agents was also exploited in vivo for T2-weighted MR imaging of rat livers. All the results showed the effectiveness of the nanoparticles in MR diagnosis.

The TGF-β1/Smad signaling pathway has been linked to hepatic fibrosis. Previous studies have shown that yellow polysaccharide can prevent the development of hepatic fibrosis. However, it is unclear whether the polysaccharide affects the TGF-β1/Smad signaling pathway. In this experiment, 50 experimental rats were randomly divided into a normal control group, model group, low GFP dose group (50 mg kg−1), medium GFP dose group (100 mg kg−1), and high GFP dose group (200 mg kg−1). A cirrhotic portal hypertension rat model was established by a CCl4 compound method. After 12 weeks of intragastric administration, the liver index of the medium dose and high dose group was significantly lower than that of the model group. The hepatic fibrosis lesions of rats in each dose group were improved to different extents, and the effect was most significant in the high dose group. The contents of ALT, AST, TBIL and CIV, PCIII, LN and HA in serum were significantly decreased. The activity of SOD and GSH-Px in the liver tissue of GFP medium and high dose groups was significantly increased and the content of MDA was significantly decreased. The contents of TNF-α, IL-1β and IL-6 were significantly decreased. The western blot results showed that the expressions of p-Smad 2/3, Smad4, PAI-1, Imp7 and Imp8 in medium dose and high dose groups were significantly lower than those in the model group, while the expression of Smad7 was significantly higher than that of the model group. The GFP-treated group was able to reduce the expression level of mi R-154 in liver tissue and increase the expression level of miR-146a. GFP has a significant intervention effect on rat hepatic fibrosis, and its mechanism may inhibit the progression of hepatic fibrosis by inhibiting oxidative stress and inflammatory response and regulating TGF-β1/Smad signaling pathway and mi RNA expression.

A catalytic system using Pd2(dba)3·(C6H6)/PPh3/CuI for Sonogashira coupling was demonstrated to synthesize a selenophene-conjugated magnesium tetraethynylporphyrin Mg-TEP-(Se-DPP)4 (2a). The catalytic system enabled four-fold cross-coupling of the four terminal alkynes of magnesium tetraethynylporphyrin with bromoselenophene-tethered diketopyrrolopyrroles (DPPs) to produce the desired star-shaped 2a in 80% yield. This molecule shows higher solubility in organic solvents, more efficient visible and near-infrared region absorption, and a narrower band gap compared with reference thiophene-conjugated congeners. Two strategies, namely, selenium substitution and end-capping, were investigated to optimize bulk heterojunction structures in the active layers of organic solar cells. The optimized device based on 2a:PC61BM exhibited the highest PCE of 6.09% among the tested devices after solvent vapor annealing, owing to efficient exciton dissociation, balanced carrier mobility, and suppressed carrier recombination in the film's ordered morphology.

An ultra-sensitive

Alpha lipoic acid (LA) is a natural compound and coenzyme with sufficient safety information for serving as a promising anticancer agent. To further clarify the mechanism of action (MoA), two Ir(III) complexes with the functionalized α-lipoic acid (N∧N-LA, N∧N, 2,2-bipyridine derivative), namely Ir1 and Ir2, were synthesized, where Ir1 possessed a half-sandwich structure with the formula [Ir(Cp*)(N∧N-LA)Cl]PF6 (Cp* = 1,2,3,4,5-pentamethyl-cyclopentadiene) and Ir2 possessed the cyclometalated structure with the formula [Ir(C∧N)2(N∧N-LA)]PF6 (C∧N = 2-phenylpyridine). Even though both complexes were constructed based on the same N∧N-LA ligand, Ir1 showed no cytotoxicity (IC50 > 200 μM), which was due to its low lipophilicity for hard penetration into the cancer cells, easy hydrolysis, and reaction with GSH. Ir2 exhibited excellent cytotoxicity (IC50 = 3.43–6.74 μM) toward diverse cancer cell lines in vitro and a promising ability to overcome the cisplatin-resistance in A549R cells. The anticancer mechanism of Ir2 in A549 cells was investigated in detail, and it was found it could localize and accumulate in the lysosomes of A549 cells, induce ROS, arrest the cycle at G0/G1, and lead to cell death by autophagy. Comparison with Ir-NH2 ([Ir(C∧N)2(N∧N-NH2)]PF6) demonstrated that introduction of the LA ligand to Ir2 could highly enhance the cytotoxicity and help to overcome the cisplatin-resistance. This study of the half-sandwich and cyclometalated Ir(III)-based anticancer agents highlighted the different MoAs toward cancer cells and provided new insights for understanding their structure–property relationships.

Multifunctional nanoclusters based on Fe

The facile fabrication of multifunctional nanocomposites (Fe3O4/HBC@F127) consisting of superparamagnetic Fe3O4 nanoparticles and fluorescent organic hexa-peri-hexabenzocoronene (HBC) molecules incorporated in block copolymer diacylphospholipid–polyethyleneglycol F127 have been demonstrated for dual mode imaging (fluorescent/MR) and drug delivery. The obtained nanocomposites were water-dispersible, stable and biocompatible, as confirmed by dynamic light scattering (DLS) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Relativity measurements showed a T2 relaxivity (r2) of 214.61 mM−1 s−1, which may be used as T2-weighted MR imaging agents. In vitro imaging studies indicated that the nanocomposites had good MR and fluorescence imaging effects with low cytotoxicity. Besides, the developed nanocomposites could also be applied as drug delivery vehicles. Doxorubicin (DOX) loaded Fe3O4/HBC@F127 nanocomposites significantly inhibited the growth of human hepatoma cells (HepG2). These findings suggested that the facile synthesized multifunctional nanocomposites may be used as a platform for dual mode imaging (both MR and fluorescence) and drug delivery.

Early diagnosis is an important requirement for the early treatment of diseases and reliable detection methods for biomarkers are indispensable tools for early diagnosis. However, recent innovations in analytical technology are rarely employed widely due to multiple factors including the requirement of specialized equipment and infrastructures. Hence, much attention has been focused on exploring universal nanoprobes for routine practices. Here, we report a chemical redox modulated switch-on fluorescence strategy based on versatile carbon dots (CDs) for probing alkaline phosphatase (ALP) and human IgG (a model target). The fluorescence of the CDs is initially quenched by Fe(III) and then restored by ascorbic acid, which is generated from the hydrolysis of ascorbic acid 2-phosphate (AAP) by the catalysis of ALP. Based on that, a simple “switch-on” fluorescence assay for ALP was designed and leads to a sensitivity of as low as 0.8 U L−1. The proposed assay is applied in ALP sensing in human serum samples. Additionally, the application of the switch-on fluorescence strategy is successfully expanded to the immunoassay of human IgG in serum from healthy adults and patients with systemic lupus erythematosus. The developed sensing system could be devised for various target sensors and has promising potential in the field of biological analysis and clinical diagnostics.

International audience; An Astragalus residue was reutilized through solid-state fermentation by Paecilomyces sinensis, which is a member of Ophiocordyceps sinensis (Berk.) Sacc. In this research, the polysaccharide from the product of solid-state fermentation primarily was studied. First, HPLC, FT-IR, and GC were applied to study the preliminary characterization of a polysaccharide (APP-II) from the solid-state fermentation product Astragalus residue and Paecilomyces sinensis. Results indicated that APP-II is a-pyran polysaccharide with an average molecular weight of 670 kD that is composed of rhamnose, arabinose, xylose, mannose, glucose, and galactose with a molar ratio of 4.0 : 4.2 : 2.0 : 41.4 : 22.5 : 25.9. Second, an immunostimulatory activity of APP-I and APP-II was detected. Results suggested that APP-I and APP-II could promote RAW264.7 cell proliferation. APP-I was used to detect the immunostimulatory activity of APP-II in vivo. The results indicated that APP-I can promote growth of immune organs, stimulate splenocyte proliferation, and enhance NK activity; this indicated that APP-II had immunostimulatory activity in vivo. All the results indicated that APP-II is a novel polysaccharide with immunostimulatory activity.

Currently, developing single-phased white light phosphors based on a single-doped activator is an efficient approach to blends of bicolor/tricolor phosphors for realizing phosphor-converted white light emitting diodes (pc-WLEDs) with a high color rendering index (CRI) and low correlated color temperature (CCT). Here, we present high CRI (Ra = 93–95) and low CCT (3500–6000 K) white lights by cosubstituting [Ca2+–P5+] for [La3+–Si4+] in the solid solution Ca(8→2)La(2→8)(PO4)6−x(SiO4)xO2:Eu2+/Eu3+ (CLPSO_Eu). The results are attributed to the presence of multi Ca2+ sites due to possible mixing nanophases and the simultaneous occupancy of Ca2+ and La3+ sites by Eu, resulting in the mixing of blue (466 nm) and green emissions (540 nm) for Eu2+, and red emission (613 nm) for Eu3+, which were perfectly confirmed using X-ray Rietveld refinement, photoluminescence spectra and extended X-ray absorption fine structure. These findings not only imply that the as-prepared CLPSO_Eu are promising single-phased white light phosphor for near-UV based WLEDs but also offer a novel avenue to design high CRI white light phosphors based on a tunable Eu2+/Eu3+.

In this research, we developed a multianalyte fluorescence sensing system through a carbon dots (CDs)-based fluorescent probe that can specifically recognize Fe(III) by fluorescence quenching. The CDs prepared using black tea by a hydrothermal method show outstanding properties like low cytotoxicity, high photostability, excellent biocompatibility, and high sensitivity. It was found that the fluorescence of CDs can be quenched by micromolar concentrations of Fe(III) in both aqueous solutions as well as living cells. It is well known that glucose can be oxidized by glucose oxidase (GOx) to release H2O2, which, in turn, can oxidize Fe(II) to Fe(III). Based on this consideration, a multianalyte sensing system was established. Therefore the quantitative analysis of Fe(III), H2O2, and glucose with detection limits of 0.25 μM, 0.82 μM, and 1.71 μM, respectively, was achieved by the simple and cost-effective multianalyte CDs sensing system constructed. The sensing system showed high photostability and negligible cytotoxicity toward HeLa cells, which enables it to be applied in the visualization of Fe(III) or H2O2 in living cells. The system was further applied in the detection of Fe(III) or glucose in human serum, and satisfactory results were obtained.

A catalytic system using Pd

The TGF-β1/Smad signaling pathway has been linked to hepatic fibrosis. Previous studies have shown that yellow polysaccharide can prevent the development of hepatic fibrosis. However, it is unclear whether the polysaccharide affects the TGF-β1/Smad signaling pathway. In this experiment, 50 experimental rats were randomly divided into a normal control group, model group, low GFP dose group (50 mg kg

MWCNT/octadecylamine hybrids with interesting structures were prepared via a simple ultrasonication and drip-drying method. The morphologies of the hybrids vary from lamellae, balls, to rose-like nanoflowers, depending on the weight ratio of the two components, which could be attributed to the introduction of nanotubes into the long-chained amine with self-organization characteristics. The paper chip sensor based on MWCNT/octadecylamine hybrid shows rapid response, high sensitivity and excellent repeatability to some volatile organic compounds, especially chloroform gas. The proposed sensing mechanism of the hybrid is via the swelling of octadecylamine upon the adsorption of organic gas, thus enlarging the nanotube distance in the MWCNT/octadecylamine hybrid and leading to the conductivity decrease of the paper chip.

We report the in situ reduction and incorporation of gold nanoparticles into graphene oxide/polyethyleneimine composites with polyethyleneimine acting as the reducing and protecting agent for the gold nanoparticles. The resulting composites with porous structure are obtained through a simple freeze-drying method with the gold nanoparticles uniformly distributed on the graphene oxide sheets. The morphology and composition of the composite are characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and Raman spectroscopy. The catalytic test indicates that the as-prepared porous gold nanoparticle-embedded composite catalyst could efficiently activate the reduction of 4-nitrophenol to 4-aminophenol. The recycling measurement reveals that the activity of the recovered catalyst decreases a little, mainly due to the restacking of the graphene sheets. Moreover, the porous composites used as packing material in chromatography column and injection syringe exhibit good catalytic performances in the rapid reduction of 4-nitrophenol, implying the potential applications of such porous heterogeneous catalysts in continuous catalytic reaction.

The facile fabrication of multifunctional nanocomposites (Fe

The Wnt/β-catenin signaling pathway has been implicated in the development of dendritic spines, which are the structural basis for the induction of long-term potentiation. We have previously shown that exposure to Pb during development causes damage to the spines on hippocampal pyramidal neurons by decreasing the activity of the Wnt/β-catenin signaling pathway. Epigallocatechin-3-gallate (EGCG), the most abundant catechin in green tea, has been shown to recover impaired hippocampal-dependent long-term potentiation in rats exposed to Pb. We report here an investigation of whether this protective function of EGCG works by regulating the Wnt/β-catenin signaling pathway to refine the formation of spines in rats exposed to Pb during development. Sprague-Dawley rat pups were exposed to Pb from parturition to weaning and EGCG (10, 25 and 50 mg kg−1) was given intraperitoneally from postnatal day 14 to postnatal day 21. We found that exposure to Pb significantly decreased the density of dendritic spines and spine head size of pyramidal neurons in the hippocampal CA1 areas; EGCG (10 and 25 mg kg−1) reversed this Pb-induced spine damage. EGCG (10 and 25 mg kg−1) also recovered the expression of Wnt7a and β-catenin phosphorylation after exposure to Pb. However, 50 mg kg−1 of EGCG did not restore the spine morphology and the activity of the Wnt/β-catenin pathway on rats exposed to Pb. EGCG did not exert any protective effect on Pb2+-induced damage in cultured hippocampal neurons when Wnt7a shRNA applied. Our results show that EGCG (within a certain dose range) has a significant protective effect on spine formation and maturation through Wnt/β-catenin signaling in young rats exposed to Pb. This effect involves the up-regulation of Wnt7a expression and the attenuation of phospho-β-catenin expression. EGCG may be a potential complementary agent in the treatment of Pb poisoning.