Development and in vitro Evaluation of Antigen‐Loaded Poly(amidoamine) Nanoparticles for Respiratory Epithelium Applications

A poly(amidoamine) with disulfide linkages in the main chain and 4‐hydroxybutyl and ω‐carboxy‐PEG groups (9:1 ratio) as side chains was prepared by Michael addition polymerization of cystamine bisacrylamide with 4‐hydroxybutylamine and ω‐carboxy‐PEG‐amine. To develop therapeutic protein formulations for improved delivery of antigen via the intranasal route, nanoparticles were prepared from this polymer by self‐assembly with p24 or ovalbumin as the model proteins and CpG as the adjuvant. The nanoparticles incorporated the antigens and adjuvant from the feed solution with high efficiency (～90 %) and have sizes of 112 and 169 nm, respectively, with low positive surface charge (～+2 mV). Formulations of the nanoparticles were shown to be nontoxic and stable for at least 10 days at room temperature. Their capacity to pass through epithelial and endothelial cell layers was evaluated in vitro by using a respiratory mucosa‐like barrier model in which monolayers of NCI H441 respiratory epithelial cells and ISO‐HAS‐1 endothelial cells were co‐cultured on both sides of a transwell filter membrane. It was shown that p24 incorporated in the nanoparticles was transported with >140 % greater efficiency through the two contact‐inhibited layers than p24 in its free form, whereas incorporation of ovalbumin in the nanoparticles leads to a 40 % decrease in transport efficiency relative to the free antigen.     

On-Line Characterization of Morphology and Water Adsorption on Fumed Silica Nanoparticles

The first wetting layer on solid nanoparticles has direct implications on the roles these particles play in industrial processes and technological applications as well as in the atmosphere. We present a technique for online measurements of the adsorption of the first few water layers onto insoluble aerosol nanoparticles. Atomized fumed silica nanoparticles were dispersed from aqueous suspension and their hygroscopic growth factors (HGF) and number of the adsorbed water layers at subsaturated conditions were measured using a nanometer hygroscopic tandem differential mobility analyzer (HTDMA). Particle morphology was characterized by electron microscopy and particle density was determined by mobility analysis. The HGFs of the size-selected particles at mobility diameters from 10 to 50 nm at 90% relative humidity (RH) varied from 1.05 to 1.24, corresponding to 2–6 layers of adsorbed water. The morphology of the generated fumed silica nanoparticles varied from spheres at 8–10 nm to agglomerates at larger diameters with effective density from 1.7 to 0.8 g/cm³ and fractal dimension of 2.6. The smallest spheres and agglomerates had the highest HGFs. The smallest particles with diameters of 8 and 10 nm adsorbed two to three water layers in subsaturated conditions, which agreed well with the Frenkel, Halsey, and Hill (FHH) isotherm fitting. In comparison to the small spheres or large agglomerates, the compact agglomerate structure containing a few primary particles increased the number of adsorbed water layers by a factor of ～1.5. This was probably caused by the capillary effect on the small cavities between the primary particles in the agglomerate.     

Polypropylene in the melt state as a medium for in situ synthesis of copper nanoparticles

Copper nanoparticles were in situ synthesized into a polypropylene matrix in the melt state. Three different routes were studied depending on the method used for the addition of a copper salt: (1) directly as powder; (2) dissolved in water; and (3) dissolved in water with a reducing agent. The first route produced microcrystal, whereas the second route allowed the synthesis of nanoparticles (～20 nm) homogeneously dispersed in the polymer matrix. By changing the concentration of the reducing agent in the copper solution (third route), a control of the copper structure in the polymer was possible and salt‐based or metal/oxide nanoparticles could be obtained. All these composites were able to release copper ions depending on the characteristic of the nanoparticles present in the polymer. Noteworthy, the resulting polymer/copper composites displayed strong antimicrobial behavior against Escherichia coli. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3406–3411, 2014     

6,6'-二甲基-2,2'-联吡啶固相萃取光度法测定水中铜的研究

根据试剂6,6' 二甲基 2,2' 联吡啶与铜(Ⅰ)的显色反应及WatersPorapakR○　Sep Park固相萃取小柱对显色配合物的固相萃取,建立了一种测定水样中μg/L级铜的新方法,在pH=4.5HAc NaAc缓冲介质中,6,6' 二甲基 2,2' 联吡啶与铜(Ⅰ)反应生成2∶1稳定配合物,该配合物可用WatersPorapakR○　Sep Park固相萃取小柱富集,小柱上富集的配合物用乙醇(内含1%醋酸)洗脱后用光度法测定,可测定水样中μg/L级的铜。该方法用于几种水样中铜含量的测定,结果令人满意。     

The monolayer behavior and transfer characteristics of phospholipids at the air/water interface

The monolayer behavior of phospholipids at the air/water interface and their transfer characteristics on the: solid substrates have been investigated with a constant-perimeter type Langmuir trough. From the surface pressure-area (Π-A) isotherm, evaluated were the cross-sectional area of an oriented molecule, phase transition, and the miscibility of mixed monolayers. The monolayer state depends on the chain length and its mobility, and by adding proper salts, the monolayers were stabilized. The miscibility of mixed monolayers was also discussed with collapse pressure and excess area. The monolayers of all lipids were transferred into only one layer on hydrophobic substrates, and up to two layers on hydrophobic substrates. The multilayer formation of dipalmitoylphosphatidic acid (I)PPA) was significantly affected by the subphase pH and the addition of multivalent salts. As a transfer promoter. DPPA or octadecylamine (ODA) was used as a component in a mixture with lipid materials, and their mixed monolayers resulted in good transfer characteristics. The transferred mass and film thickness of DPPA, determined by using a quartz crystal microbalance (QCM) and by an ellipsometry respectively, were proportional to the number of transfer. The lattice spacing of DPPA was 20.3 Å per layer by ellipsometry, and 22.78 Å per layer by X-ray diffraction. These indicated that the transferred multilayers had well-defined layered structures of Y-type.     

离子凝胶法制备壳聚糖纳米微粒

采用离子凝胶法,以不同浓度壳聚糖溶液与多聚磷酸盐(TPP)溶液配比反应制备壳聚糖纳米微粒,观察了壳聚糖、多聚磷酸盐浓度、壳聚糖与多聚磷酸盐的质量比和反应体系pH值对纳米微粒制备的影响。在壳聚糖与多聚磷酸盐溶液浓度分别为0.6~3.0 mg/mL与0.5~1.5 mg/mL时,保持质量比在3∶1~6∶1之间,可稳定得到壳聚糖纳米微粒;当pH值为5.0~6.0时壳聚糖纳米微粒保持稳定,当pH>7.0则出现沉淀。     

The investigation of the passive behaviour of copper in weakly acid and alkaline solutions and the examination of the passive film by esca and ISS

The passive behaviour of copper is examined in weakly acid and alkaline solutions. The current peaks of the potentiodynamic polarization curves are related to the formation and reduction of passivating oxide layers. These layers have been examined by ESCA and ISS. A duplex structure of the oxide is found with copper I oxide at the metal surface covered by copper II hydroxide for sufficiently positive potentials. The thickness of the anodically formed oxide is deduced from the charges of cathodic reduction in phosphate buffer pH = 7.0 and 8.0 and borax buffer pH = 9.2. 10 to 14 Å of Cu₂O are found for the three buffer solutions not changing decisively with the potential of passivation. The thickness of the covering Cu(OH)₂ is increasing with the potential in the range of 0.30 V_H to 1.20 V_H up to 33, 23, and 19Å in the buffer solutions pH = 7.0, 8.0, and 9.2, respectively. From the increase of the thickness of the Cu(OH)₂ layer with the potential an electrical field strength of ～ 5<d10⁶ V cm^?1 is deduced for the outer part of the passive layer.     

表面活性剂(PVA)浓度对电子束制备纳米铜的影响

在水溶液中,常温常压下使用聚乙烯醇(PVA)为表面活性剂,用电子束辐照方法可以成功制备纳米铜粉。利用紫外可见分光光度计(UV)和激光粒度衍射仪(LSPSDA)考察了表面活性剂浓度对纳米铜粒径分布和团聚的影响。在一定范围内随着PVA浓度的增大纳米铜的粒径减小到13nm。X射线衍射(XRD)和透射电子显微镜(TEM)结果表明PVA浓度为0.88g/100mL,pH值在5~9之间时,能得到纯的纳米铜,其粒径分布为15~40nm。     

铜含量测定方法研究

建立二乙基二硫代氨基甲酸钠(DDTC或铜试剂)光度法测定铜含量的方法。实验结果表明,在pH值4～5的条件下,Cu-DDTC配合物的最大吸收波长为460 nm,摩尔吸光系数为1.0×104L/(mol.cm),线性范围为0～2.4μg/mL,加标回收率为94.9%～104.1%,RSD为3.1%～5.7%。该方法可用于样品中常量铜的测定,并且大量的银存在时也不干扰铜的测定。经用于银包铜粉样品中铜含量的测定,结果符合要求。     

The effect of CuO coatings on the electrokinetic properties of stone wool fibres determined by streaming potential measurements

Commercial stone wool fibres were modified with copper(II) oxide coatings. This oxide is widely used in processes of surface modification for filter materials to improve its bacterial retention. The microorganisms are already susceptible to low concentrations of copper in contrast to humans for which copper is an inert material in the concentration range. Additionally, the coatings changed the electrokinetic properties of the fibres. As a result, the isoelectric point (IEP) of the untreated fibres was shifted from acidic towards a more basic pH range. A positive or no charge on the surface of the fibres allows them to be a substrate for the positively charged adsorbents of negatively charged waterborne contaminants with the use of electrostatic adsorption. The coatings were prepared by dip coating with the use of two different coating precursors: the aqueous suspension of CuO nanoparticles and aqueous solutions of copper(II) nitrate trihydrate or copper(II) acetate or a mixture of thereof. The zeta potential of the modified fibres was determined by a streaming potential method. The adhesion of the coatings was tested by flushing and ultrasonication of the modified fibres. The isoelectric point of the fibres was shifted towards a more basic pH range for all precursors with the largest impact of the copper(II) nitrate trihydrate precursor. This coating changed the IEP of the fibres from 4.1 to 8.3 pH value. The highest calculated coverage of the coatings was in the range of 54% and was obtained by using copper(II) nitrate trihydrate/CuO nanoparticles precursor. Although, we do not predict such modified fibres to act as a standalone water filter, we believe they have the potential to be an excellent support material for active adsorbents.     

Room-Temperature Electrochemical Assembly of Copper/Cuprous Oxide Nanocomposites

Nanocomposite films of copper metal and cuprous oxide, Cu₂O, are electrodeposited at room temperature from alkaline solutions of copper(II) lactate. The electrode potential oscillates spontaneously if the films are deposited galvanostatically. The oscillation period is a function of pH, varying from 69 seconds at pH 8.7 to 11 seconds at pH 9.7. No oscillations are observed if the pH is below 8.5 or above 10. The phase composition of films deposited at 0.5 mA/cm² is a function of pH. The composition varies from nearly pure copper (93 mole%) at pH 8, to 42 mole% copper at pH 9.5, to pure cuprous oxide when the pH exceeds 10. The observation of quasi-periodic potential oscillations suggests that the nanocomposites are layered. The calculated faradaic thickness of cuprous oxide is 5–8 nm, and the thickness of the copper layer is 1–11 nm. The thickness of each of the layers increases as the pH is lowered.     

Studies into the swelling of gelatine films using a scanning fluid dynamic gauge

Fluid dynamic gauging (FDG) has been developed to measure both the thickness and strength (cohesive or adhesive) of a range of fouling deposits, in situ and in real time. We report the development of a scanning FDG device (sFDG) with fully automated movement and deposit thickness measurement. Thickness-time profiles can be collected for several points on the surface over the course of a single experiment. sFDG is employed here to study the cleaning kinetics of model gelatine fouling layers when contacted with aqueous solutions at different pHs and temperatures, and with a commercial dishwasher formulation containing enzymes.Solution pH is an important parameter: above ～pH 10.6 the gelatine layers swell markedly, due to protonation of the amino acids proline and hydroxyproline, and subsequent charge repulsion within the gel. An unusual behaviour (discontinuity) is reported during swelling in the commercial formulation. It is proposed that hydration of the deposit and an extent of swelling (ratio of the final to the initial deposit thickness) of ～12 is necessary before the enzymes can promote deposit removal.     

Effect of thermal treatment on the electrothermographic and electrical properties of poly(acrylonitrile butadiene styrene)

Studies on the electrothermographic and conductivity behaviour of poly(acrylonitrile butadiene styrene) (ABS) films of different thermal pretreatments were carried out. The resistivity in ABS layers stored at 50°C was found to be low (～ 10¹⁵ Ω · cm). The charge acceptance and its retention also is poor. The reason for that is the adsorption of water molecules. The layers, when thermally treated at 100°C or more for 5 h, show an enhanced resistivity (～ 10¹⁷ Ω · cm at 50°C) and hence an improvement in charge acceptance as well as in charge retention. Environmental and storage conditions as well as thermal treatment during layer preparations have no effect on the temperature dependence of the resistivity beyond 110°C.     

乐果微污染原水的碱解-活性炭处理研究

在去除模拟污染源水中乐果的实验室和中试试验中,考察了pH、粉末活性炭投加量对去除效果的影响.结果表明,当原水中乐果的质量浓度为0.095～0.286 mg·L~(-1)、pH为9.5～10时,乐果的去除率都随着粉末活性炭投加量的增加而提高,平均去除率为35.4%～68.3%;采用石灰碱解+粉末炭吸附预处理乐果超标1倍(质量浓度0.2 mg·L~(-1))左右的原水,在混凝沉淀工艺之前调节pH至9.5左右,常规出水的乐果含量可达到GB 5749-2006的要求.     

带羧基乳胶颗粒的制备、聚集以及与重氮树脂的自组装

从苯乙烯、丙烯酸丁酯和丙烯酸制备了表面带COOH的不同粒径的乳胶颗粒 (～ 10 0～40 0nm)。研究了因水分挥发由毛细管力引起的乳胶颗粒的聚集 ,以及这些乳胶颗粒和含N2 + 的高分子 (重氮树脂 ,Mn～ 2 5 0 0g/mol)的自组装 ,结合紫外光照 ,制备了高分子与乳胶粒交替的三明治 (sandwich)结构的超薄膜 ,结果表明 ,层与层间的光反应是高分子与乳胶粒成功组装的关键。由于光照中 ,层与层间的离子键已转变为共价键 ,这种超薄膜对极性溶剂和盐水溶液非常稳定 ,在DMF、c(NaCl) =0 1mol/L的水溶液中 ,室温下 (～ 2 0℃ )分别浸泡 2 4h ,组装膜仍完好无损。     

High-quality reduced graphene oxide-nanocrystalline platinum hybrid materials prepared by simultaneous co-reduction of graphene oxide and chloroplatinic acid

Reduced graphene oxide-nanocrystalline platinum (RGO-Pt) hybrid materials were synthesized by simultaneous co-reduction of graphene oxide (GO) and chloroplatinic acid with sodium citrate in water at 80°C, of pH 7 and 10. The resultant RGO-Pt hybrid materials were characterized using transmission electron microscopy (TEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy, and thermogravimetric analysis. Platinum (Pt) nanoparticles were anchored randomly onto the reduced GO (RGO) sheets with average mean diameters of 1.76 (pH 7) and 1.93 nm (pH 10). The significant Pt diffraction peaks and the decreased intensity of (002) peak in the XRD patterns of RGO-Pt hybrid materials confirmed that the Pt nanoparticles were anchored onto the RGO sheets and intercalated into the stacked RGO layers at these two pH values. The Pt loadings for the hybrid materials were determined as 36.83 (pH 7) and 49.18% (pH 10) by mass using XPS analysis. With the assistance of oleylamine, the resultant RGO-Pt hybrid materials were soluble in the nonpolar organic solvents, and the dispersion could remain stable for several months.     

Modification of TiAlV Alloys with Hybrid Layers Containing Metallic Nanoparticles Obtained by the Sol–Gel Method: Surface and Structural Properties

The aim of the work was to obtain hybrid coatings containing silver, copper, and zinc nanoparticles on the TiAlV medical alloy via a sol–gel process. The developed layers were designed to bring about a bactericidal and fungicidal effect, as well as for protection against surgical scratches during the implantation of implants used in veterinary medicine. In this work, the authors focused on evaluating the microstructure (SEM + EDS); the structure (XRD, FTIR); and the surface properties, such as wettability, free surface energy, and roughness of layers with various concentrations of metallic nanoparticles (2 and 5 mol %). Our results confirmed that the sol–gel method enables the easy manufacturing of hybrid layers endowed with different porosity values as well as various shapes and sizes of metallic nanoparticles. A higher concentration of nanoparticles was observed on the surface containing 5 mol % of metallic salts. The highest degree of homogeneity was obtained for the layers containing silver nanoparticles. In addition, the silver nanoparticles were round and had the smallest dimensions, even below 20 nm. The FTIR and XRD structural studies confirmed the presence of an organosilicon matrix containing all three types of the metallic particles. We conclude that the higher concentration of nanoparticles influenced the alloy surface parameters.     

Influence of subphase on the orientation of helical peptides at interface

Boc-(l-Leu-Aib)_n-OBzl (n=8, 12, 16; OBzl represents benzyl ester) was spread on water or a mixture of water and methanol (1/1 v/v) and the orientation of the helical peptides on subphase was investigated by FTIR-reflection-absorption spectroscopy. When the peptides were spread at a liquid phase on subphase, the peptides took a vertical orientation, which was not attainable by compression of peptide monolayers initially spread at a gas phase on subphase. However, the peptide monolayers on water could not be transferred on gold with keeping the vertical orientation. On the other hand, when the peptides were spread on a mixture of water and methanol, the orientation of helical peptides was closer to vertical than that on water and the monolayers were transferred repeatedly on gold to form multilayers with a vertical orientation. The suppression of orientation change upon transfer of the peptide monolayer is considered to be due to reduction of electrostatic interaction between the peptide and the image dipole when the peptide is spread on a mixture of water and methanol.     

Electrochemical behaviour and physical properties of Cu/Co multilayers

Cobalt/copper multilayer formation was analysed over different substrates in order to control the bilayer thickness and quality of coatings. Using a sulphate-citrate bath, at pH 4.7, electrodeposition conditions were optimised to prepare good alternate Cu/Co layers with high efficiency, by minimising the oxidation of cobalt layers during copper deposition. For multilayers with cobalt and copper layers of several nanometers, direct observation by scanning electron microscopy (SEM) or tapping mode-atomic force microscopy (TMAFM) gives layer thickness in agreement with the value calculated from deposition charges. Therefore, this calculation has been used to estimate the thickness of the thinner layers for which direct observation was difficult or impossible. A relation between the response of different characterisation methods was found. When the thickness of each layer in Cu/Co multilayers is >1.8-2 nm, potentiodynamic stripping experiments show separate peaks related to cobalt and copper oxidation. In these conditions, magnetoresistance of the coating is low. For thinner layers, the stripping response shows overlapping peaks or even a single oxidation peak. In these conditions the magnetoresistance begin to increase.     

细菌纤维素的静态发酵及物理性质研究

以木醋杆菌为生产菌,在静态培养条件下,通过改变碳源及初始pH值等条件,初步研究了发酵过程中pH值、残糖以及纤维素产量的变化,并初步测定了纤维素的性质。结果发现在葡萄糖、麦芽糖、蔗糖、甘露醇四种碳源中,甘露醇获得的纤维素产量最高;菌体在初始pH值4～6范围内生长较好,pH值为4.5时产量最高;扫描电镜观察菌体长度大约为2μm,宽度为0.8μm左右,纤维直径分布在10～80nm之间,其中80%主要分布在20～50nm,在30～40nm之间最多;红外光谱显示了细菌纤维素葡聚糖的特征吸收;热重分析表明,细菌纤维素最大失重速率温度为342.9℃,在622.2℃,失重率达到72.26%;每克湿纤维素膜含水130～210g,含水率超过99%,而每克干纤维素膜能吸水3.1～5.0g。