Hierarchical antibiotic delivery system based on calcium phosphate cement/montmorillonite-gentamicin sulfate with drug release pathways.

Antibiotic-loaded calcium phosphate cement (CPC) has emerged as a promising biomaterial for drug delivery in orthopedics. However, there are problems such as the burst release of antibiotics, low cumulative release ratio, inappropriate release cycle, inferior mechanical strength, and poor anti-collapse properties. In this research, montmorillonite-gentamicin (MMT-GS) was fabricated by solution intercalation method and served as the drug release pathways in CPC to avoid burst release of GS, achieving promoted cumulative release ratios and a release cycle matched the time of inflammatory response. The results indicated that the highest cumulative release ratio and release concentration of GS in CPC/MMT-GS was 94.1 ± 2.8 % and 1183.05 µg/mL, and the release cycle was up to 504 h. In addition, the hierarchical GS delivery system was divided into three stages, and the kinetics followed the Korsmeyer-Peppas model, the zero-order model, and the diffusion-dissolution model, respectively. Meanwhile, the compressive strength of CPC/MMT-GS was up to 51.33 ± 3.62 MPa. Antibacterial results demonstrated that CPC/MMT-GS exhibited excellent in vitro long-lasting antibacterial properties to E. coli and S. aureus. Furthermore, CPC/MMT-GS promoted osteoblast proliferation and exhibited excellent in vivo histocompatibility. Therefore, CPC/MMT-GS has favorable application prospects in the treatment of bone defects with bacterial infections and inflammatory reactions.

Study on the poly(methyl methacrylate-acrylic acid)/calcium phosphate cement composite bound by chelation with enhanced water absorption and biomechanical properties.

Polymethylmethacrylate (PMMA) bone cement has been widely used as a critical material for fixing prostheses and filling bone defects. The shrinkage of PMMA bone cement was addressed by the additives, however, the uneven integral water absorption and expansion performance as well as the deteriorated mechanical properties of the modified bone cement after immersion in phosphate buffered saline (PBS) and simulation body fluid (SBF) affected the long-term stability after implantation. Calcium phosphate cement (CPC) is a biomaterial with promising applications in orthopedics, whose hydration reaction provides an important driving force for the transfer of water. Besides, the mechanical properties of CPC can be enhanced with the curing process. In this study, CPC was utilized to modify the poly(methyl methacrylate-acrylic acid) [P(MMA-AA)] bone cement. The results demonstrated the successful construction of interconnected CPC water delivery networks in the P(MMA-AA)/CPC composite, the water absorption ratio and expansion ratio of the composite were up to 131.18 ± 9.14% and 168.19 ± 5.44%, respectively. Meanwhile, the transformation of CPC water delivery networks into rigid mechanical support networks as well as the chelation interaction between organic-inorganic enhanced the mechanical properties of the composite after immersion, the compressive strength after immersion reached 62.97 ± 0.97 MPa, which was 27.65% higher than that before immersion. The degradation ratio of the composite was up to 13.76 ± 0.23% after 9 days of immersion, which was 16.4% higher than that of CPC. Furthermore, composites exhibited superior biocompatibility as the release of Ca2+. Therefore, P(MMA-AA)/CPC composite serves as a promising medical filling material for clinical use.

Construction of SrTiO3-BiOCl composite catalyst via facial microwave hydrothermal for highly efficient photocatalytic activity towards organic compounds degradation.

This work mainly focuses on the preparation and performance study of SrTiO3-BiOCl composite photocatalysis. The SrTiO3-BiOCl photocatalysts are prepared via the facial microwave hydrothermal method. XRD, UV-vis DRS, SEM, TEM, XPS, N2 adsorption and desorption isothermal experiment, FT-IR, and PL are applied to characterize the prepared samples. The spherical particles of SrTiO3 grow on the flaky BiOCl, and the crystal size is uniform and evenly disperses on the BiOCl. The catalytic performance of the samples was evaluated over the degradation rates of methylene blue(MB). Typically, the clearance rates of MB reached to 99.65% over SrTiO3-BiOCl-50% under visible light, which was much higher than that of SrTiO3 and BiOCl (55.86%, 79.79%, respectively). The active species capturing experiments and ESR showed that the holes (h+) and ·OH are playing the main roles in the degradation process.

MiR-513a-3p promotes radiation-induced apoptosis of human lung cells by inhibiting glutathione S-transferase P1.

Radiotherapy is a common treatment for lung cancer. However, radiation pneumonitis caused by radiotherapy can affect the quality of life and prognosis of lung cancer patients. miR-513a-3p has been found to sensitize human lung adenocarcinoma cells to chemotherapy by targeting glutathione S-transferase P1 (GSTP1). Here, we found that x-ray induced the apoptosis of BEAS-2B and miR-513a-3p expression in a dose- and time-dependent manner, and miR-513a-3p-mimic significantly increased x-ray induced apoptosis, while miR-513a-3p-inhibitor significantly decreased x-ray induced apoptosis. Dual luciferase gene reporter system showed that miR-513a-3p targeted to inhibit the expression of GSTP1 in BEAS-2B cells. Moreover, knockdown of GSTP1 significantly increased, while overexpression of GSTP1 decreased the apoptosis of BEAS-2B induced by x-ray. Importantly, overexpression of GSTP1 significantly reduced miR-513a-3p-mimic elevated x-ray -induced apoptosis in BEAS-2B cells. In conclusion, x-ray caused increased expression of miR-513a-3p, and miR-513a-3p promoted x-ray-induced apoptosis of human lung cells by inhibiting GSTP1.

Novel dual-sensitization electrochemiluminescence immunosensor using photopermeable Ru(bpy)3 2+ -doped chitosan/SiO2 nanoparticles as labels and chitosan-decorated Nafion/MWNTs composites as enhancer.

A novel dual-sensitization electrochemiluminescence (ECL) immunosensor for the detection of tumour protein prostate specific antigen (PSA) at trace level using Ru(bpy)3 2+ -doped chitosan/SiO2 nanoparticles (Ru(bpy)3 2+ /chitosan/SiO2 NPs) as the first signal enhancers was fabricated. Due to chitosan with excellent pore forming capacity, these nanoparticles possess porous structures and better photopermeability, and therefore have higher luminescence efficiencies compared with Ru(bpy)3 2+ /SiO2 NPs reported in previous publications. Conversely, chitosan with good biocompatibility and high hydrophilicity was electrochemically decorated onto a Nafion/multiwall carbon nanotubes (Nafion/MWNTs) modified electrode surface and used as the second sensitizing matrix to seize large amounts of prostate specific capture antibody (Ab1 ). The chitosan-decorated Nafion/MWNTs composites exhibited a 5.5-times higher ECL intensity than the unadorned Nafion/MWNTs films. Also, without additional reagents, such as (3-aminopropyl)triethoxysilane (APTS), the one-step functionalized Ru(bpy)3 2+ /chitosan/SiO2 NPs provided a large number of active arms to connect with PSA-detected antibodies (Ab2 ) through the amino groups in chitosan. After a sandwich immunoreaction, the PSA antigen and Ru(bpy)3 2+ /chitosan/SiO2 NPs-labelled Ab2 were sequentially captured onto the Ab1 /chitosan/Nafion/MWNTs-modified electrode surface. The ECL signal increases were linearly related to the PSA antigen concentrations and ranged from 0.01 pg·mLl-1 to 10.0 pg·mLl-1 . Under the optimized experimental conditions, the immunosensor displayed excellent sensitivity and selectivity. The detection limit was as low as 3.4 fg·mLl-1 , equivalent to, or better than, those of the reported ECL immunosensors for PSA.

p-Cu2O/n-ZnO heterojunction thin films with enhanced photoelectrochemical properties and photocatalytic activities for norfloxacin.

A two-step electrochemical deposition technique was applied to fabricate p-Cu2O/n-ZnO heterojunction thin films. The influence of the deposition potential upon photoelectric performance of the prepared samples was examined utilizing XRD, XPS, SEM, UV-Vis, and electrochemical tests. The results show that the deposition potential has a substantial influence on the properties of the prepared samples. When the deposition potential is -0.45 V, the peak intensity of the (111) crystal plane of the prepared heterojunction is the highest, the band gap increased, and the morphology changes obviously compared to those of Cu2O. The transient photocurrent value is three times that of pure Cu2O, and the charge transfer resistance significantly reduced. The p-Cu2O/n-ZnO heterojunction has a high carrier concentration. Photocatalytic degradation experiments show that degradation rate of norfloxacin increases by 14.4%-76.6%. The enhanced photocatalytic performance of Cu2O is mainly due to the formation of a high-quality heterojunction and the change in the energy band structure, which promotes the transfer rate of the carrier and the separation of photogenic electron hole pairs, thus effectively improving the catalytic efficiency of photocatalysts. Active species detection experiments reveal that positive hole and superoxide anion radical play leading roles in norfloxacin molecule decomposition. In addition, a possible mechanism for the photocatalytic performance of p-Cu2O enhanced by n-ZnO is proposed according to the analysis of the bandgap of p-Cu2O and n-ZnO, along with the built-in electric field formed in the p-n heterojunction. This study provides an effective and alternative method for removing norfloxacin residues in wastewater.

Comparative study on photocatalytic material activity of BiOBr flower microspheres and sheet structure.

BiOBr nanosheets and BiOBr flower-like microspheres were prepared by hydrothermal method and solvothermal method, respectively. On this basis, BiOBr nanosheets were modified by reducing agent reduction, preparing successfully Bi/BiOBr nanosheets. The XRD, SEM, UV-VisDRS, XPS and UV-vis spectrophotometry were used to characterize the morphological structures, physical properties and surface element composition of the photocatalysts. In addition, photocatalytic activity was analyzed by the ability to degrade the antibiotic norfloxacin. The results indicated that after irradiation of 500 W xenon lamp for 180 min, the degradation rates for norfloxacin of BiOBr nanosheets, BiOBr flower like microspheres, and Bi/BiOBr photocatalyst were 34.7%, 72.1%, and 97.2%, respectively. And the degradation of norfloxacin was in accordance with the first order kinetic model. Compared with BiOBr nanosheets, the other two samples have better visible light photocatalytic activity, of which the photocatalytic activity of Bi/BiOBr was the highest. And the half-life of norbofloxacin degraded by Bi/BiOBr was shortened to 25 min. In addition, The results of capture experiments indicated that the main active groups involved in the degradation reaction of norfloxacin by Bi/BiOBr photocatalysts under visible light conditions were ⋅O2- and h+. The reason why the activity of the Bi/BiOBr material photocatalyst increased is that the heterojunction formed by the wider bandgap BiOBr and the lower Fermi level Bi metal element effectively inhibits the recombination of holes and photogenerated electrons, which leads to the enhancement of oxidation capacity.

Preparation and analysis of photochromic behavior of carboxymethyl chitin derivatives containing spiropyran moieties.

1'-(2-Acryloxyethyl)-3,3'-dimethyl-6-nitrospiro[2 H-1-benzopyran-2,2'-indoline] (SPA) was synthesized and grafted onto a water-soluble carboxymethyl chitin (CMCH) macromolecule to prepare a photochromic copolymer (CMCH-g-SPA). The structure of CMCH-g-SPA was characterized by Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) analysis, X-ray diffraction (XRD) analysis, water-solubility evaluation, and UV-vis spectroscopy. XRD patterns of CMCH-g-SPA revealed that grafting copolymerization disrupts the CMCH semicrystalline structure, thus improving water solubility. UV-vis spectroscopy results supported the negative photochromic behavior of the merocyanine (MC) form of CMCH-g-SPA (CMCH-g-MCA) present in a water solution of the target copolymer. In addition to high solvent polarity, the intermolecular and intramolecular electrostatic attraction between the indolenine cation and the COO- anion were found to be influencing factors, which stabilize these MC form of spiropyran groups grafted onto CMCH. In a water solution, visible light bleaching was completed over a short period (8 minutes) under artificial visible light irradiation and the thermal coloration reaction, whose rate constant at 25 °C was 4.64 × 10-4 s-1, which fit the first-order reaction equation. After ten photochromic cycles in water solution, the relative absorption intensity of CMCH-g-MCA decreased by 7.92%.

The antioxidant compounds isolated from the fruits of chinese wild raspberry Rubus Chingii Hu.

Raspberry, the fruit of Rubus Chingji Hu, is a widely distributed economic staple food in China. It has long been used as a traditional medicine in mainland China to treat kidney enuresis, nocturnal emission and premature ejaculation in clinic. In this paper, six known compounds (1 - 6) were purified from the fruits of Rubus chingji. Their structures were elucidated as (16α)-16,17-dihydroxy-ent-kauran-2-one17-O-ß-D-glucopyranoside (1), (16R) -16,17-dihydroxy-ent-kaurane-2-one (2), 3,3'-di-O-methylellagic acid 4-(5''-acetyl)-α-L-arabinofuranoside (3), quercilicoside A (4), esculetine (5) and ethyl-ß-D-glucoside (6). All the compounds were isolated from Rubus Chingji Hu for the first time. Compounds 3 and 5 shown distinctive free radical scavenging activities in DPPH and FRAP assays. In addition, no cytotoxicity was observed for compounds 3 and 5 against different cancer cells, suggesting that they might be useful as potential antioxidant agents against various reactive oxygen species.[Formula: see text].

Morphology-controlled Fabrication of SnO2 /ZnO Nanocomposites with Enhanced Photocatalytic Performance.

In this work, a series of novel SnO2 /ZnO nanocomposites with different morphologies were fabricated via a facile hydrothermal technique followed by calcination in air. The morphological, structural and photocatalytic properties of the SnO2 /ZnO nanocomposites were studied using different methods. The results showed that the synthesized nanocomposites possessed crystal phases of wurtzite hexagonal phase ZnO and tetragonal rutile phase SnO2 . In addition, the morphologies of SnO2 /ZnO nanocomposites strongly depended on the molar ratios of Sn and Zn. Compared with ZnO and SnO2 , the SnO2 /ZnO nanocomposites exhibited considerably higher degradation efficiency for the photodegradation of methylene blue and quinolone antibiotics under mercury lamp irradiation. The SZ-2 nanospheres exhibited the highest degradation efficiency of 95.81%, which was about 2.63 times higher than that of ZnO nanoparticles. Moreover, the trapping experiments confirmed that ˙OH played the dominant role in MB degradation. Finally, the charge carriers potential transfer pathway and photocatalytic degradation mechanism were put forward. This study provides an economical way to prepare hybrid nanocomposites with controlled morphology for practical applications in the photocatalytic degradation of organic dyes and residual antibiotics.

Preparation and performance of Cu2O/TiO2 nanocomposite thin film and photocatalytic degradation of Rhodamine B.

A constant current electrodeposition approach was employed to prepare Cu2O/TiO2 nanocomposite thin film. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Raman, ultraviolet visible light spectrophotometer (UV-Vis), and photoluminescence (PL) measurements were used to characterize and analyze the thin film microstructure, surface morphology, and photoelectric properties. The effect of annealing treatment on the thin film properties is discussed. The response surface methodology (RSM) was employed to optimize the Rhodamine B (RhB) photocatalytic degradation by thin films, and the quadratic multinomial mathematical model was established. The photocatalytic degradation process of RhB was also studied. The results indicate that the prepared Cu2O thin film was of high purity, with a (111) crystal plane preferred orientation. The average particle diameter was approximately 100-200 nm, and the absorbing boundary was approximately 600 nm. After annealing treatment, the absorbing boundary and open-circuit voltage increased, and Cu2O thin film exhibited an obvious absorbance response in the visible-light range. The established model has better fitness and higher reliability, and the R2 value of established quadratic model is 0.9818. The optimal degradation conditions were obtained by RSM. Under optimum conditions, the RhB degradation rate could reach 98.4% in 3 h and the total organic carbon (TOC) removal rate was 48.2%. Recycling results reveal that RhB degradation rate can still reach 94.5% after eight cycles.

Preparation and characterization of Cu2O nano-particles and their photocatalytic degradation of fluroxypyr.

Cu2O nano-particles were prepared by the liquid-phase reduction method and the effect of the dispersant was studied. The microstructure, surface morphology and optical properties of Cu2O nano-particles were characterized by X-ray diffractometer, X-ray photoelectron spectroscopy, nitrogen static adsorption, scanning electron microscope, particle size analysis, ultraviolet visible light spectrophotometer and photoluminescence spectrometer. The photocatalytic degradation of fluroxypyr using Cu2O was studied by the response surface methodology, and the quadratic multinomial mathematical model was established. The results indicated that the Cu2O crystal particles prepared using the dispersant of polyvinylpyrrolidone were of high purity with the preferential orientation of (111). The average particle size was 605.4 ± 124.8 nm, the specific surface area was 22.641 m2/g, the band gap was approximately 2.04 eV and the absorption edge was about 650 nm. R2 of the established quadratic model was 0.9973 and had good fitness, indicating that the established model was reliable. The optimal degradation conditions were obtained as follows: the initial concentration of fluroxypyr was 11.17 mg/L, the pH of the solution was 12.0 and the H2O2 concentration was 15 mg/L. The degradation rate of fluroxypyr could reach 83.2% and the relative error was 1.20%. After nine times of recycling, more than 75% of fluroxypyr could be degraded.

Synthesis, characterization and evaluation cytotoxic activity of silver nanoparticles synthesized by Chinese herbal Cornus officinalis via environment friendly approach.

Cornus officinalis has been widely used as a precious herb and as the tonic food to improve kidney function in China. Its fruits have been used in many traditional Chinese medicine prescriptions to treat kidney diseases, diabetes, cancer and shock. In this study, a new eco-friendly approach for green synthesis of silver nanoparticles (AgNPs) by using the fruits of Cornus officinalis aqueous extract as a reducing and stabilizing agent. The so-synthesized AgNPs showed quasi-spherical in shape with uniform dispersal and an average mean size of 11.7nm. Water soluble biomolecules such as flavonoids and/or anthocyanins from the extract played important roles in the nanoparticles formation. The AgNPs displayed distinctive cytotoxicity activities against human prostate cancer (PC-3) and human liver cancer (HepG2) cell lines. The results provided a low cost, nontoxic and eco-friendly approach for synthesizing metal nanoparticles to explore alternative anticancer agents on the way fighting against cancer in future.

A novel bioconversion for value-added products from food waste using Musca domestica.

Food waste, as a major part of the municipal solid waste has been generated increasingly worldwide. Efficient and feasible utilization of this waste material for productivity process is significant for both economical and environmental reasons. In the present study, Musca domestica larva was used as the carrier to conduct a bioconversion with food waste to get the value-added maggot protein, oil and organic fertilizers. Methods of adult flies rearing, culture medium adjuvant selection, maggot culture conditions, stocking density and the valorization of the waste have been explored. From the experimental results, every 1000g culture mediums (700g food waste and 300g adjuvant) could be disposed by 1.5g M. domestica eggs under proper culture conditions after emergence in just 4days, 42.95±0.25% of which had been consumed and the culture medium residues could be used as good organic fertilizers, accompanying with the food waste consumption, ∼53.08g dried maggots that contained 57.06±2.19% protein and 15.07±2.03% oil had been produced. The maggot protein for its outstanding pharmacological activities is regarded as a good raw material in the field of medicine and animal feeding. Meanwhile, the maggot oil represents a potential alternative feedstock for biodiesel production. In our study, the maggot biodiesel was obtained after the procedure of transesterification reaction with methanol and the productivity was 87.71%.

Preparation and properties of visible light responsive Y3+ doped Bi5Nb3O15 photocatalysts for Ornidazole decomposition.

Nanoparticle of Bi(5)Nb(3)O(15) doped with Y(3+) was prepared for the first time by the sol-gel method combined with impregnation. The degradation of Ornidazole reacting with Y(3+)-Bi(5)Nb(3)O(15) was investigated to explore the feasibility of using Y(3+)-Bi(5)Nb(3)O(15) to treat antibiotics in wastewater. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, UV-vis diffuse reflectance spectrum and X-ray photoelectron spectroscopy. The results showed that the Y(3+)-Bi(5)Nb(3)O(15) exhibited single-crystalline orthorhombic structure with small particle size (20-100 nm); additionally, its UV-vis absorbance edges significantly shift to the visible-light region. The as-prepared nanoparticles exhibited a high photocatalytic activity in the decomposition of Ornidazole and several possible pathways of degradation of Ornidazole were proposed according to the results of ultra-performance liquid chromatography tandem mass spectrometry.

Diterpenoid alkaloids from a Tibetan medicinal plant Aconitum richardsonianum var. pseudosessiliflorum and their cytotoxic activity.

The chemical constituents from Aconitum richardsonianum var. pseudosessiliflorum were investigated. The roots of this plant were extracted three times with 90% EtOH at the room temperature. The ethanol extracts were combined and concentrated under reduced pressure to yield residue, which was suspended in water and successively partitioned with chloroform. The chloroform extraction was isolated and purified by silica gel and Sephadex LH-20 column chromatography. Six compounds were isolated and elucidated as delelatine (1), isodelpheline (2), 3-acetylaconitine (3), isoatisine (4), nordhagenine A (5) and yunaconitine (6). Compounds 1-5 were obtained from Aconitum Brunneum for the first time. Compound (1) showed significant cytotoxic activities (IC50= 4.36 µM) against the human tumor cell line P388.

[Determination of 88 pesticide residues in cranberry plant extract by gas chromatography-triple quadrupole tandem mass spectrometry].

A method by using a modified QuEChERS (quick, easy, cheap, effective, rugged and safe) and gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS) was established to analyze 88 pesticide residues in cranberry plant extract. The sample was extracted with acetone-hexane (1: 1, v/v) containing 1% acetic acid, then cleaned-up by ethylenediamine-N-propyl silyl (PSA) and graphite carbon (GCB). The extract was determined by GC-MS/MS in multi-reaction monitoring (MRM) mode, and external standard method was applied to quantified the pesticides. All the 88 pesticides showed good linearity in the range of 0. 001 - 0. 2 mg/L, and the limits of quantification (LOQs, S/N > or = 10) were all less than 31. 5 microg/kg. The average recoveries of all the pesticides were in the range of 71. 4% to 116. 6% at three spiked levels of 5, 25 and 50 microg/kg in cranberry plant extract, with the relative standard deviations (RSDs) of 2. 4% - 16. 9%. The results demonstrated that this method is simple, rapid and suitable for the determination of 88 pesticide residues in cranberry plant extract. The analytical sensitivity and accuracy can meet the requirements of multiple pesticide residue analysis.

Chemical constituents from Delphinium chrysotrichum and their biological activity.

A new diterpene alkaloid named delphatisine C (1) has been isolated from aerial parts of Delphinium chrysotrichum along with three known norditerpenoid alkaloids delpheline (2), delbrunine (3), and delectinine (4). Their structures were characterized on the basis of their spectral data. All of them were determined by SRB assay for their cytotoxicity, and compound (1) showed significant cytotoxic activities (IC(50)=2.36 µmol/L) against the A549 cell line.

[Transport kinetics of Pb(II) through bulk liquid membrane using PC-88A as carrier].

The effects of stirring speed, carrier concentration and reaction temperature on the transport of Pb(II) ion through bulk liquid membrane were studied with chloroform as membrane solvent and 2-ethylhexyl phosphonic acid-mono-2-ethylhexylester as carrier. The Pb(II) ions concentrations of feed phase and stripping phase were assayed by atomic absorption spectroscopy. The kinetic parameters, including apparent rate constants of Pb(II) ion extraction and re-extraction reactions, the maximum concentration of Pb(II) ion in the liquid membrane, the time of the maximum value of maximum concentration of Pb(II) ion in the liquid membrane and the maximum entry and exit fluxes of Pb(II) ion through the liquid membrane of the extraction and stripping reactions, were evaluated. The apparent activation energy value is 31.65 kJ x mol(-1) for extraction and 23.11 kJ mol(-1) for stripping. The results indicate that good agreement between experimental data and theoretical predictions could be achieved and the kinetics of Pb(II) transport could be evaluated by two consecutive irreversible pseudo-first order reactions. In this condition the chemical reaction is a procedure of controlled reaction rates.

A new norditerpenoid alkaloid from Aconitum taipaicum.

To investigate the chemical constituents of the roots of Aconitum taipaicum, silica gel column chromatography was used for the isolation and purification of compounds. A new norditerpenoid alkaloid, isodelelatine (1), along with five known alkaloids, atisine (2), delfissinol (3), liangshanine (4), hypaconitine (5) and delelatine (6) were isolated and identified. The structure of the new compound was elucidated on the basis of spectral data.