可作为疫苗佐剂的云芝多糖磷酸钙纳米粒的制备与表征

我们设想通过磷酸钙药物载体与多糖的结合制备新型的疫苗佐剂,以提高疫苗传递效率,增强免疫应答。首先对云芝粗多糖进行提纯处理,随后利用高碘酸钠(Na IO4)氧化云芝多糖(PSK)得到多醛基产物,再以帕米膦酸二钠(PA)修饰,得到PSK-PA,利用红外光谱法对其产物进行鉴定。采用共沉淀法,制备功能化磷酸钙(PSK-CAP)纳米粒,利用动态光散射(DLS)粒度仪对纳米粒性能进行对比分析选取最优结果,并通过扫描电子显微镜(SEM)观察最优条件下纳米粒的形貌。随后利用载有鸡卵清蛋白(OVA)为模型抗原的纳米粒(PSKCAP-OVA)验证对细胞活性影响,同时观察RAW264.7细胞对其吞噬能力。通过一系列的表征发现,纳米粒平均粒径为100 nm左右,且分散性良好,PSK-CAP-OVA纳米粒毒性较小,并且RAW264.7细胞更倾向于吞噬装载OVA的纳米粒,可以提高胞内OVA的浓度。总之,PSK-CAP纳米粒可为后续研究佐剂类型提供参考。

Rapid Preparation Process of Silver Nanoparticles by Bioreduction and Their Characterizations

Bioreduction as a novel nanoparticle synthesizing technology attracts increasing attention. Dried cells of the bacterium Aeromonas sp. SH10 rapidly reduced [Ag（NH3）2]^＋ to Ago in the solution into which some amount of OH^- was introduced. The surface plasmon resonance centered at 425 nm on the UV-vis spectra and five broad Bragg reflections on the XRD pattern showed that stable silver nanoparticles were formed during the bioreduction process. TEM and SEM observations suggested that the silver nanoparticles were uniform in size and well dispersed on the cells and in the solution. Therefore, silver nanoparticles could be prepared rapidly by this bioreduction technology.

Preparation and characterization of poly(amic acid)-stabilized silver nanoparticles

Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy.Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5,demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth,accompanied by soft impingement effect.XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles.The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.

Low temperature synthesis and thermal properties of Ag-Cu alloy nanoparticles

Ag-Cu alloy nanoparticles were synthesized by simple low temperature chemical reduction method using metal salts（acetate/sulphates） in aqueous solution with sodium borohydride as reducing agent.The chemical reduction was carried out in the presence of nitrogen gas in order to prevent the oxidation of copper during the reaction process.The alloy nanoparticles were characterized by XRD,UV-Vis,particle size analysis,EDS,TG-DTA and SEM analysis.From the XRD analysis,the crystallite sizes of the prepared samples were calculated using Scherrer formula and the values were found to be in the range of 15 nm.UV-Vis studies conform the formation of alloy nanoparticles.EDS analysis shows the presence of silver and copper in the samples.The SEM observation reveals that the samples consist of grains with average grain size up to 40 nm,and the particle size dependant melting point was studied by TG-DTA.

Reverse Microemulsion Synthesis and Characterization of Pd-Ag Bimetallic Alloy Catalysts Supported on Al_2O_3 for Acetylene Hydrogenation

Pd-Ag bimetallic alloy nanoparticles were synthesized by the reverse microemulsion method, and then deposited on A1203 to form the supported catalyst. The nanoparticles of Pd-Ag and Pd-Ag/AI203 samples were characterized by UV/ Vis, HRTEM, EDX, XRD, and XPS. The test results indicated that Pd-Ag bimetallic alloy nanoparticles with a size of about 2 nm and a face-centered cubic （fcc） structure were formed in the measured area of microemulsion. The growth of nanopar- ticles was effectively limited within the droplet of micoremulsion. TEM image exhibited that the Pd-Ag alloy nanoparticles were well-dispersed on the A1203 support. The catalytic performance of various catalysts for selective hydrogenation of acetylene showed that a higher acetylene conversion and selectivity to ethylene upon acetylene hydrogenation was achieved on a nano-sized Pd-Ag bimetallic catalyst with a Pd/Ag alloy supported molar ratio of 1：1.5.

Activity and stability of bacterial cellulase immobilized on magnetic nanoparticles

Magnetic nanoparticles（Fe3O4） were synthesized by co-precipitating Fe^2＋ and Fe^3＋ ions in an ammonia solution and treating under hydrothermal conditions.Cellulase was immobilized onto Fe3O4 magnetic nanoparticles via glutaraldehyde activation.Using response surface methodology and Box-Behnken design,the variables such as magnetic nanoparticle concentration,glutaraldehyde concentration,enzyme concentration,and cross linking time were optimized.The Box-Behnken design analysis showed a reasonable adjustment of the quadratic model with the experimental data.Statistical contour plots were generated to evaluate the changes in the response surface and to understand the relationship between the nanoparticles and the enzyme activity.Scanning electron microscopy,X-ray diffraction analysis,and Fourier transform infrared spectroscopy were studied to characterize size,structure,morphology,and binding of enzyme onto the nanoparticles.The stability and activity of the bound cellulase was analyzed using various parameters including pH,temperature,reusability,and storage stability.The immobilized cellulase was compared with free cellulase and it shows enhanced stability and activity.

Synthesis and Characterization of MgSb2O6 Trirutile-Type in Low Presence Concentrations of Ethylenediamine

The nanoparticles MgSb206 with trirutile-type structure were prepared by colloidal method using ethylanediamine （0.5 and 0.75 mL）, following a calcination at 800 ℃. After, those powders were analyzed by x-ray obtaining a tetragonal structure with cell parameters, a = 4.64 A and c = 9.25 A and special group P42/mnm. Using a scanning electron microscopy were analyzed the powders calcined at 800 ℃, showing the formation of micro-plates, micro-rods, nanoparticles and morphology as rice grains. Employing a transmission electron microscopy, were found nanostructures hexagonal shaped with sizes of- 33.6 nm （0.5 mL） and 28.6 nm （0.75 mL）.

Construction and Characterization of Gal-Chitosan Graft Methoxy Poly(Ethylene Glycol)(Gal-CS-mPEG) Nanoparticles as Efficient Gene Carrier

In the present study, galactosylated chitosan(Gal-CS) was conjugated with methoxy poly(ethylene glycol)(m PEG) as a hydrophilic group. The structure of Gal-CS-m PEG polymer was characterized and the nanoparticles(NPs) were prepared using ironic gelation method. The study was designed to investigate the characteristics and functions of Gal-CS-m PEG NPs. The morphology of Gal-CS-m PEG NPs was observed by SEM and it was a compact and spherical shape. The size of the NPs was approximately 200 nm in diameter under the ideal process parameters. The interaction between Gal-CS-m PEG NPs and p DNA, and the protection of p DNA against DNase I and serum degradation by Gal-CS-m PEG NPs were evaluated. Agarose gel electrophoresis results showed that Gal-CS-m PEG NPs had strong interaction with p DNA at the weight ratio of 12:1, 4:1 and 2:1 and could protect p DNA from DNase I and serum degradation. Gal-CS-m PEG NPs exhibited high loading efficiency and sustainable in vitro release. The blood compatibility studies demonstrated that Gal-CS-m PEG NPs had superior compatibility with erythrocytes in terms of aggregation degree and hemolysis level. Gal-CS-m PEG NPs showed no cytotoxicity on L929 cells, which is a normal mouse connective tissue fibroblast, but showed inhibitory effects on the proliferation of Bel-7402 cells, which is a liver cancer cell line. In conclusion, Gal-CS-m PEG NP is a bio-safe and efficient gene carrier with potential application in gene delivery.

Preparation and characterization of oleanolic acid-loaded solid lipid nanoparticles for oral administration

Oleanolic acid-loaded solid lipid nanoparticles（OA-SLNs）were prepared by using an improved emulsion-solvent evaporation method.The size,zeta potential,encapsulation efficiency,and loading efficiency of OA-SLNs were（104.5±11.7）nm, （-25.5±1.8）mV,（94.2±3.9）%,and（4.71±0.15）%,respectively.The morphology was illustrated by TEM as sphere stuffed particles.The XRD and DSC spectra confirmed that the OA molecules were dispersed uniformly into SLN matrixes.The results of in vitro release test suggested that OA was released slowly at a rate of 4.88%per hour from SLN preparation,which was consistent with the Zero-order Released Model.In addition,OA-SLNs were stable in artificial gastric juice and artificial intestinal juice.Together,our results provided new data for the potential application of OA-SLNs in oral administration.

In-situ characterization of metal nanoparticles and their organic coatings using laser-vaporization aerosol mass spectrometry

The development of methods to produce nanoparticles with unique properties via the aerosol route is progressing rapidly. Typical characterization techniques extract particles from the synthesis process for subsequent offiine analysis, which may alter the particle characteristics. In this work, we use laser-vaporization aerosol mass spectrometry （LV-AMS） with 70-eV electron ionization for real-time, in-situ nanoparticle characterization. The particle characteristics are examined for various aerosol synthesis methods, degrees of sintering, and for controlled condensation of organic material to simulate surface coating/functionalization. The LV-AMS is used to characterize several types of metal nanoparticles （Ag, Au, Pd, PdAg, Fe, Ni, and Cu）. The degree of oxidation of the Fe and Ni nanoparticles is found to increase with increased sintering temperature, while the surface organic-impurity content of the metal particles decreases with increased sintering temperature. For aggregate metal particles, the organic-impurity content is found to be similar to that of a monolayer. By comparing different equivalent-diameter measurements, we demonstrate that the LV-AMS can be used in tandem with a differential mobility analyzer to determine the compactness of synthesized metal particles, both during sintering and during material addition for surface functionalization. Further, materials supplied to the particle production line downstream of the particle generators are found to reach the generators as contaminants. The capacity for such in-situ observations is important, as it facilitates rapid response to undesired behavior within the particle production process. This study demonstrates the utility of real-time, in-situ aerosol mass spectrometric measurements to characterize metal nanoparticles obtained directly from the synthesis process line, including their chemical composition, shape, and contamination, providing the potential for effective optimization of process operating parameters.

Electrochemical Characterization of a Porous Pt Nanoparticle ＂Nanocube-Mosaic＂ Prepared by a Modified Polyol Method with HCI Addition

Porous and single crystalline platinum （Pt） nanoparticles （NPs） have been successfully synthesized by reduction of H2PtC16.6H20 and then investigated by optical spectroscopy and transmission electron microscopy. H2PtCI6-6H20 was reduced using ethylene glycol in the presence of polyvinylpyrrolidone under highly acidic conditions （pH 〈 1） to form single crystalline Pt particles about 5 nm in size. These particles were then stacked via {100} facets, forming 50-nm length porous nanocubes with a mosaic structure. The porous Pt NPs exhibited excellent catalytic properties for methanol oxidation. In particular, the electrochemical surface area was -63 m2/g, five times higher than that for non-porous Pt NPs prepared using a conventional method. We suggest that the high catalytic activity of porous Pt NPs is due to a combination of the crystalline structure having exposed {100} facets and a porous morphology.

Occurrence, Structure and Mineral Phases of Nanoparticles in an Anthrosol

Soils contain various kinds of crystalline to amorphous solid particles with at least one dimension in the nanoscale （〈 100 nm）. These nanoparticles contribute greatly to dynamic soil processes such as soil genesis, trace element cycling, contaminant transport, and chemical reaction. The nano-sized fraction of an Anthrosol was obtained to determine the occurrence, chemical composition, structure, and mineral phases of nanoparticles using high-resolution transmission electron microscopy （HRTEM） equipped with an energy-dispersive X-ray spectroscopy. Selected area electron diffraction or the fast Fourier transform of high-resolution images was used in structural characterization of the nanoparticles with HRTEM. Two nanoscale mineral types, i.e., mineral nanoparticles and nanomi- nerals, were observed in the Anthrosol. Mineral nanoparticles in soil included well crystalline aluminumsilicate nanosheets, nanorods, and nanoparticles. Nanosheets with a length of 120-150 nm and a width of about 10-20 nm were identified as chlorite/vermiculite series. The presence of clear lattice fringe spacing in HRTEM image of nanoparticles indicated that mineral nanoparticles had a relatively good crystallinity. The nanomineral ferrihydrite also existed in the Anthrosol. The HRTEM images and the particle size distribution histogram suggested that these ferrihydrite nanoparticles were quite homogeneous, and had a narrow size distribution range （1-7 nm） with a mean diameter of 3.6 4- 1.6 nm. Our HRTEM observation indicated that mineral nanoparticles and nanominerals were common and widely distributed in Anthrosols. HRTEM and selected area diffraction or lattice fringe spacing characterization provided further proofs to the structure of nanoparticles formed in soil.