Abstract: The purpose of this paper is to prepare and evaluate a gene delivery system resulted from the intercalation of DNA with magnetic layered double hydroxide (MLDH). The structure and property of the MLDH/DNA hybrids were studied using XRD, FTIR and TG characterization. The cytotoxicity and protection effect of MLDH were evaluated by MTT assay and gel electrophoresis assay. MLDH exhibited lower cytotoxicity than other inorganic nanoparticles. Under physiological conditions, MLDH could protect DNA from enzymatic degradation. Our results confirmed that MLDH can be used safely and effectively as non-viral vectors for gene targeting therapy in form of MLDH/DNA composite.
Abstract: In this paper, we synthesized a CdHgTe type water-soluble quantum dots, combined in the next time with the drug delivery system "dextran - magnetic layered double hydroxide - fluorouracil" (DMF), built a new nanostructures platform QD@DMF for blending the fluorescent probe function of quantum dot together with the magnetic targeting curative effect of the DMF system. The Fluorescence spectrophotometer, Ultraviolet spectrophotometer, TEM and XRD were used to characterize the luminescent properties, particle morphology and phase characteristics of the QD@DMF samples. The experiments on cell imaging were carried out by laser con-focal scan microscopy technique. Results showed that the CdHgTe QDs could be successfully grafted onto the surface of the DMF system through electrostatic coupling, forming a special structure based on magnetic layered double hydroxide with a near-infrared emission wavelength in 575~780 nm. Compared with QDs, the QD@DMF composite could significantly improve the cell imaging effect, the label intensity increased with the magnetic field intensity and obeyed the linear relationship Dmean = 1.760+0.013B. The fluorescent magnetic nanoparticles maintained not only the super-paramagnetic of DMF but also the photoluminescence properties of the QDs, implicating that the QD@DMF composite may be an effective multifunction tool for optical bio-imaging and magnetic targeted therapy.
Abstract: High-throughput drug screening microfluidic chip has good biocompatibility and faveriable functional integration, which is the excellent platform for high-throughput screening. Importantly, FRET (Fluorescence Resonance Energy Transfer) technology is the most efficient detection means at present. In this paper, we introduce the development of drug screening microfluidic chip on cellular level and the application of FRET technology on cell detection. Further, we discusse the possibility of FRET applied in the field of microfluidic biochip.
Abstract: Porous Hyaluronan/β-tricalcium phosphate composite scaffolds were synthesized through lyophilizing and subsequent heterogeneous crosslinking method. The morphology of the composite scaffolds were investigated by scanning electron microscopy (SEM). The swelling behavior, mechanical property, degradation behavior and cell adhesion ability of samples were also studied. The results revealed that hyaluronan mainly contributed to the polymer matrix and water adsorption, whereas β-TCP acted as a reinforcement to strengthen the porous structure, while too much β-TCP would make the structure collapse. The pose size of obtained scaffolds ranges from100μm to 200μm and the porosity decreased with the increase of β-TCP content. The degradation behavior and cell adhesion test indicated that increasing hyaluronan concentration can effectively improve the degradability of scaffolds and the incorporation of β-TCP improved the cell adhesion performance. Thus a simple way to prepare hyaluronan-based composite scaffolds was provided, which could be potentially used as an tissue engineering material.
Abstract: Ta-xZr (x = 90, 80, 70, 60 at.%) alloys with good mechanical properties and high density were prepared by powder metallurgy method and vacuum sintering technology. The surface morphologies and mechanical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS). The results showed that lamellar Ta was observed with no second phase during the sintering process. The tensile strength and the Young's modulus increased with the Ta contents firstly and then decreased, and varied with the Ta contents in the range of 60.5 ± 5.03~163.0 ± 10.11 MPa and 4.5 ± 0.47~11.8 ± 1.16 GPa, respectively. In conclusion, The Ta-70Zr alloy is potentially useful in the hard tissue implants for its mechanical properties and biocompatibility.
Abstract: The anodic aluminum oxide template was prepared and used to fabricate polyacrylonitrile (PAN) nanowire arrays by mechanical hydraulic method, which provides a new idea for the preparation of polymer nanowires. By further carbonize the PAN nanowires at elevated temperatures, the porous nitrogen-rich carbon nanowires could be directly obtained and used as lithium-ion batteries anode material. The nitrogen-rich carbon nanowire based anode exhibited high initial capacities and maintained an outstanding reversible lithium storage capacity of 317.12 mAh g-1 after 50 cycles at a current density of 30 mA g-1, combined with an excellent rate capability of 317.17, 296.70, 265.02, 234.71, 177.02 mAh g-1 under the current density of 30, 50, 100, 200, 500 mA g-1 respectively. Further, this nitrogen-rich carbon nanowire material also has unique advantages in catalysis, supercapacitors and hydrogen storage application potential due to the porous carbon nanowire structure and the large amount of nitrogen doping.
Abstract: A facile method was developed to synthesize amorphous carbon coated nano-sized silicon and graphite by using glucose or pitch as organic carbon source, nano-sized silicon particles were uniformly coated onto the artificial graphite by combined ball milling and spray drying pyrolysis, and the effect of binder types, binder amounts on the precursor morphology, feed rate and spray pressure on the electrochemical performance were investigated in detail. The partial size, surface morphology and electrochemical performances of the as-synthesized powders were analyzed by particulate size description analyzer (PSDA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and constant current charge/discharge tools. It is found that, citric acid and binder are important for improving the free-aggregation of nano-sized silicon and the morphologyof combined silicon and graphite. Therefore, under the optimal experimental conditions, amorphous carbon from pitch coated nano-sized silicon and graphite composite anodes exhibits much higher electrochemical performance. It can deliver the first discharge specific capacity of 796.3mA·h/g at a current density of 100 mA/g, as well as 85% of initial coulombic efficiency. Additionally, the discharge specific capacity retains 724.9mA·h/g, and the discharge capacity retention of a half cell system is 91% after 50 cycles.
Abstract: Nano-silicon carbon coated and combined with different graphite matrixes was synthesized by ball milling，and spray dying-pyrolysis methods. The physical properties of Si/C composites were detected by X-ray diffraction（XRD），scanning electron microscopy（SEM），and all composites were completely coated by a carbon layer. Their electrochemical performances were studied by galvanostatic cycle and electrochemical impedance spectra. These analyses show that the discharge specific capacity of composited anode based on expanded graphite exhibits the best comprehensive electrochemical performance such as cycle stability and initial charge/discharge efficiency among various composites，owing to the co-effect of expanded graphite and amorphous carbon layer as the structural stabilizer and conductive additives to prevent the volume change and enhance the electronic conductivity of the composites. The discharge specific capacity is 700.9 mAhg-1 at a current density of 100mAg-1，initial charge/discharge efficiency is 77.4%. After 30 cycles，the capacity retention rate can reach 87.7%.
Abstract: To understand the phase composition and improve the magnetic performances of Ce2Fe14B-type alloys, the ribbons of Ce16Fe95-xCoxB8 (x=0-4.0) were prepared by melt-spinning at a quench wheel velocity of 40 m/s. The phase composition and magnetic properties of Ce16Fe95-xCoxB8 (x=0-4.0) alloys were investigated. XRD results indicated that the main phase existed in the as-spun ribbons is Ce2Fe14B. The amorphous formation ability and thermal stability of as-spun ribbons were enhanced by trace cobalt addition. Co-doped samples had higher Curie temperature compared with bare Ce2Fe14B, which signified that Co atoms could substitute for Fe directly into Ce2Fe14B phase. The corrosion potential of alloys from-1089mV (vs. SCE) to-1077mV (vs. SCE) which indicated that the Co-doped provided better corrosion protection properties for the Ce-Fe-B magnet compared with bare substrate.