紫锥菊多酚-纳米银复合物的绿色制备及表征

紫锥菊多酚(Echinacea polyphenol)为菊科植物紫锥菊的茎叶、根提取物,主要作为免疫调节剂及免疫刺激素,具有抗病毒、抗真菌、抗肿瘤及杀虫、消炎的药理作用。试验通过单因素试验优化紫锥菊多酚-纳米银复合物的制备工艺,最终得到合成过程中的最佳体积比为3∶7,硝酸银浓度为0.02 mol/L,反应时间为120 min和反应温度为100℃,并对最佳合成工艺制得的纳米银复合物进行了表征考察。结果表明,紫锥菊多酚-纳米银复合物呈现不规则的球形,大部分纳米银直径位于100 nm以下,分布系数小,粒径分布均匀;电位为-8.05 mV,纳米银复合物比较稳定;体外释放率试验表明,紫锥菊多酚-纳米银复合物有良好的缓释性能。稳定性试验表明,在4℃条件下,纳米银复合物稳定性较好。说明通过绿色合成法制备的紫锥菊多酚-纳米银复合物,有利于减少投药量,提高药物疗效,为紫锥菊多酚在临床兽医上的使用提供了新的方法。

Long-term Antibacterial Properties and Bond Strength of Experimental Nano Silver-containing Orthodontic Cements

The purpose of this study was to evaluate the long time antibacterial properties and shear bond strength of experimental nano silver-containing cements （NSC）. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at five different weight ratios to obtain a series of nano silver-containing cements, then the antibacterial properties of three orthodontic cement products and five NSC samples were evaluated by the direct contact test （DCT） and the agar diffusion test （ADT）. The DCT, which was based on turbidness determination of bacterial growth in 96-well microtiter plates, was performed in both fresh and aged for 1 day, 1 week, 2 weeks, 3 weeks, 4 weeks, 6 weeks, and 8 weeks tested materials. The shear bond strengthes of three orthodontic cement products and five NSC samples were examined using a universal testing machine. The ADT results indicated that there were no significant differences between NSCs and ORTHO LC fresh specimens. In the DCT experiment, all fresh silver nanoparticles-containing tested samples presented powerful antibacterial properties, but they gradually lost the effective antimicrobial agents with the extension of aging time. Finally, none of the tested materials maintained its antibacterial property after aging for 8 weeks. A gradually decreasing trend of bond strength presented with the increasing incorporation of nano silver base inorganic antibacterial powder into the glass ionomer cement, even though all the tested material specimens reached the ideal bond strength range. We may conclude that NSCs can contribute to decrease the demineralization rate around brackets without compromising bond strength.

Synthesis of morphology-controlled silver nanostructures by electrodeposition

Nanostructured silver was obtained by potentiostatic electrolysis.The effects of ionized surfactant(sodium dodecanesulphonate)and the substrate(Cu and Ti)on the morphology of depositions were investigated.It is found that morphologies of silver nanostructures can be simply controlled via change of the substrate.Spherical Ag nanoparticles with narrow size distribution were obtained by electrodeposition in Ag NO3-SDS aqueous solution on copper substrate.In the case of titanium substrate,silver dendrite structures were obtained.Despite of different morphologies,XRD and TEM results showed that the as-prepared samples belong to face-centered cubic silver structure with good crystallinity.The formation mechanism of different silver nanostructures was discussed.

Antibacterial and Preservation Effects of Silver-doped TiO_2 Nanoparticles on Nanfeng Citrus

[Objective] This study aimed to investigate the antibacterial and preservation effects of silver-doped nano-TiO2 on Nanfeng citrus. [Method] Silverdoped nano-TiO2 preservative film was prepared, to investigate its preservation effects on Nanfeng citrus ripe fruits under novel preservation conditions and detect the influences of nano-composite coating on physiological quality indicators of Nanfeng citrus ripe fruits. [ Result ] Compared with the control, applying nano-compesite coating preservation technology could prevent fruit corruption and water loss and delay the rapid reductioh in contents of citric acid and Vc, without adverse influences on fruit quality. [ Conclusion] Silver-doped nano-TiO2 composite coating can be promoted and applied in frozen storage and preservation practices of Nanfeng citrus.

Antibacterial Properties of Nano Silver-containing Orthodontic Cements in the Rat Caries Disease Model

The purpose of this study was to evaluate the antibacterial properties of experimental nano silver-containing cements（NSCs） using rat caries disease model. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at three different weight ratios to obtain a series of nano silver-containing cements, then two orthodontic cement products and three NSC samples were implanted into rat caries disease model, and their antibacterial properties were evaluated by the scanning electron microscope（SEM）. Moreover, the rat caries disease model were established by inoculating cariogenic bacteria S mutans into antibiotics treated rat mouths and feeding with cariogenic diet. The tested materials were bonded on the surface of the buccal half crowns of the upper fi rst premolar, and then fi xed under the rats＇ front teeth lingual side to acquire enough retention. The SEM results indicated that the growth of streptococcus mutans was very active in group of Transbond XT. One month later, S mutans scattered on the GC Fuji ORTHO LC surface, and then the number signifi cantly increased and arranged in chains after three months. In groups of NSC2, NSC3 and NSC4, the number of S mutans presented the downward trend and tended to disperse individually with the increase of silver nanoparticle content. We may conclude that the incorporation of silver nanoparticle enhanced GC Fuji ORTHO LC the adhesion restrain and killing effect to S mutans.

Decoration of activated carbon nanotubes by assembling nano-silver

A facile solution processed strategy of synthesizing nano silver assembled on carbon nanotubes （CNTs） at room temperature was put forward. Activated carbon nanotubes were used as precursors for preparing silver-decorated nanotubes. The nature of the decorated nanotubes was studied using transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, and energy-dispersive X-ray spectroscopy （EDX）. The inert surfaces of carbon nanotubes were activated by introducing catalytic nuclei via an oxidation-sensitization-activation approach. Activated carbon nanotubes catalyzed the metal deposition specifically onto their surfaces upon immersion in electroless plating baths. The method produced nanotubes decorated with silver. The extent of silver decoration was found to be dependent on fabrication conditions. Dense nano silver assembled on nanotube surfaces could be obtained by keeping a low reaction rate in the solution phase. The results here show that this method is an efficient and simple means of achieving carbon nanotubes being assembled by nano metal.

纳米银和 1-MCP 处理对月季切花的保鲜作用

研究了纳米银和1-MCP处理对月季切花‘卡罗拉’瓶插寿命和花径、相对鲜重(RFW)和瓶插液吸收(VSU)、相对叶绿素含量和丙二醛(MDA)含量、相对电导率以及抗氧化能力的调节作用。结果表明:与对照相比,纳米银和1-MCP单独处理与组合处理均能显著提高花瓣还原力,提升抗坏血酸过氧化物酶(APX)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,降低花瓣中丙二醛(MDA)含量和叶片中相对电导率,并抑制叶绿素含量的下降。与纳米银和1-MCP单独处理相比,纳米银和1-MCP组合处理对延长月季切花瓶插寿命、增大切花花径、促进切花吸水、维持切花的质膜稳定性和提升切花的抗氧化能力更为有效。总之,纳米银和1-MCP组合处理可通过维持切花的水分平衡和质膜稳定性、提高切花的抗氧化能力、降低切花的膜脂质过氧化水平来延长月季切花的瓶插寿命。

Electrical properties of nano-silver/polyacrylamide/ethylene vinyl acetate composite

Nano-Ag particles/polyacrylamide （PAM） composites were synthesized by γ irradiation method and then blended with ethylene vinyl acetate （EVA）. Dielectric behaviors of the Ag/PAM/EVA composites are investigated as a function of both the concentration and size of Ag particles. When concentration of the Ag fillers is rarely low, dielectric anomalies were first observed in contrast to the traditional percolation theory. As concentration of Ag increases, volume resistivity and breakdown field strength are enhanced, loss tangent （tan δ） reduced and dielectric constant kept invariable. In addition, the above variation became larger when the diameter of the Ag nano-particles is smaller. Such dielectric anomalies may be understood by considering the unique ＂Coulomb Blockade Effect＂ of the nano-sized Ag particles.

Preparation of UV-curable Nano-silver Antimicrobial Agent and Its Application in Non-woven Fabric

Nano-silver and waterborne polyurethane(WPU)composite emulsion was synthesized.The average diameter of silver nanoparticles(SNPs)was about 20 nm,and the average diameter of WPU was 101.32 nm.The anti-bacteria finishing of a polypropylene non-woven fabric(NWF)was carried out by ultraviolet finishing technology and the double dipping twin-roll method.The standard AATCC100 was used to test the antimicrobial activity of the samples.The results showed that the antimicrobial rates of Klebsiella pneumoniae(K.pneumoniae)and Staphylococcus aureus(S.aureus)were above 90%,which indicated that the NWF finishing had good antimicrobial activity.In addition,the thermal stability,mechanical properties,whiteness and contact angle of antimicrobial finishing nonwovens were characterized.The results showed that the performance of antimicrobial nonwovens was stable at 300℃.The breaking strength was better than that of untreated nonwovens,and the contact angle reached 119.1°.

Trace Level Gas Sensing Characteristics of Nano-Crystalline Silver Decamolybdate

A soft-chemical method has been developed for the synthesis of nano-crystalline powders of silver decamolybdate. Gas sensing characteristics of this composition both in porous pellet and thin film configurations were investigated. The compound Ag6Mo10O33 was found to sense selectively ammonia at 503 K. Above 503 K it has significant cross sensitivity to petroleum gas (PG). Spin coated thin films exhibited selective sensing towards PG.

Temperature Dependent Surface Resistivity Measures of Commercial, Multiwall Carbon Nanotubes (MWCNT), and Silver Nano-Particle Doped Polyvinyl Alcohol (PVA) Films

Pure and doped Polyvinylidene difluoride (PVDF) films, for the detection of infrared radiation, have been well documented using the mechanism of pyroelectricity. Alternatively, the electrical properties of films made from Polyvinyl Alcohol (PVA) have received considerable attention in recent years. The investigation of surface resistivities of both such films, to this point, has received far less consideration in comparison to pyroelectric effects. In this research, we report temperature dependent surface resistivity measurements of commercial, and of multiwall carbon nanotubes (MWCNT), or Ag-nanoparticle doped PVA films. Without any variation in the temperature range from 22°C to 40°C with controlled humidity, we found that the surface resistivity decreases initially, reaches a minimum, but rises steadily as the temperature continues to increase. This research was conducted with the combined instrumentation of the Keithley Model 6517 Electrometer and Keithley Model 8009 resistivity test fixture using both commercial and in-house produced organic thin films. With the objective to quantify the suitability of PVDF and PVA films as IR detector materials, when using the surface resistivity phenomenon, instead of or in addition to the pyroelectricity, surface resistivity measurements are reported when considering bolometry. We found that the surface resistivity measurements on PVA films were readily implemented.

Simulation and analysis of phase-sensitive surface plasmon resonance sensor based on enhanced optical transmission through arrays of nanoholes in silver films

A high spatial resolution, phase-sensitive Surface Plasmon Resonance(SPR) sensor based on Extraordinary Optical Transmission(EOT) is proposed to monitor the binding of organic and biological molecules to the silver surface. The 2D nanohole-array configuration is well suited for dense integration in a sensor chip. The optical geometry is collinear, which simplifies the alignment with respect to the traditional Kretschmann arrangement for SPR sensing. Various design parameters of the device have been studied by simulation. The heterodyne technique is used to improve the sensitivity. The optimization results indicate that the sensor has the advantages of achieving high resolution and a wide dynamic range simultaneously.

Silver Slate展示Nano-tex织物收藏品

最近，Silver State贸易公司展示了由Silver State fabrics首次收藏的Nano—tex织物。

Sin-QuEChERS Nano净化柱结合气相色谱-串联质谱法快速筛查石斛中84种农药残留

利用Sin-QuEChERS Nano净化柱结合气相色谱-串联质谱(GC-MS/MS)分析,建立了石斛基质中84种不同极性农药残留的快速筛查方法。比较了采用不同的提取溶剂(1%乙酸乙腈、丙酮)和不同的提取方式(加水浸泡和不加水浸泡)下目标物的提取效率。利用金钗石斛样品系统比较了Sin-QuEChERS Nano法与经典的基质固相分散法(dSPE)、固相萃取法(SPE)、QuEChERS法的净化效果及提取回收率,以及净化效果较好的Sin-QuEChERS Nano法与dSPE法基质效应的差异。目标物经DB-1701MS石英毛细管色谱柱(30 m×0.25 mm×0.25μm)程序升温分离,GC-MS/MS多反应监测(MRM)模式检测,基质匹配溶液外标法定量。通过GC-MS/MS检测方法对金钗石斛和铁皮石斛中的84种代表性农药进行了方法学验证。结果表明:各目标物在不同范围内呈良好的线性相关,相关系数(r^(2))均>0.990,方法的检出限(LOD,S/N=3)为1.5~5.8μg/kg,方法的定量限(LOQ,S/N=10)为5.0~15.0μg/kg。在两个水平下,目标农药的加标回收率为68.7%~116.2%,相对标准偏差(RSD,n=6)均低于15%。与其他经典的前处理方法相比,Sin-QuEChERS Nano法在净化效果方面表现更好,该法不仅可以有效去除色素、有机酸、碱性干扰物等物质,还可以节省样品制备时间,避免溶剂转移造成的损失,无需进一步涡旋或离心,是一种简单而有效的提取物纯化程序。该方法灵敏、快速、简便、可靠,有效地提高了石斛中农药快速筛查时的检测效率,具有较强的实际应用价值。此外,所开发的方法可以进一步扩展目标农药的类型,并可以用于检测其他更多食品及中药材中的农药残留。

Simple-QuEChERS Nano结合GC-MS/MS同时检测全血中的97种农药

建立了Simple-QuEChERS Nano结合气相色谱-串联质谱(GC-MS/MS)同时检测血液中97种农药的方法,并对基质条件、提取溶剂以及净化材料进行了优化。0.5 mL血液样品经3倍水稀释混匀,使用2.0 mL乙酸乙酯提取后振荡、离心,过Simple-QuEChERS Nano净化柱及0.22μm有机微孔滤膜后,采用多反应监测模式(MRM)进行分析。结果显示,97种农药在一定质量浓度范围内线性关系良好(r2≥0.9873),除丙烯菊酯(检出限和定量下限分别为11.03、36.76 ng/mL)外,其余农药的检出限为0.06~4.27 ng/mL,定量下限为0.18~14.24 ng/mL。采用空白全血进行加标回收实验,97种农药在100、200、400 ng/mL 3个加标水平下的回收率为32.2%~120%,日内精密度为1.9%~11%,日间精密度为3.6%~13%。该方法由传统QuEChERS方法改进,绿色环保、操作简单、快速高效,可用于血液中多种农药的同时检测,用于实际案件血液样品中农药的筛查与定性定量检验,获得了良好的结果。

基于Ag@Cu-MOF/GCE传感器检测VC的研究

合成制备具有多变体结构的银@铜有机骨架纳米复合材料(Silver@copper organic skeleton nanocomposites,Ag@Cu-MOF)并用玻碳电极(Glassy carbon electrode,GCE)构建Ag@Cu-MOF/GCE以对VC进行快速检测分析。通过对Ag@Cu-MOF和磷酸盐缓冲溶液(Phosphate buffer solution,PBS)的优化确定Ag@Cu-MOF/GCE的最佳工作条件。结果显示Ag@Cu-MOF具有良好的导电性和电催化作用,可有效提高Ag@Cu-MOF/GCE的灵敏度。VC浓度与其对应的氧化峰电流在0.5~1500μmol/L呈线性关系,R2=0.9987,检出限(S/N=3)为0.1942μmol/L,明显优于其它传感器,且Ag@Cu-MOF/GCE对常见共存物葡萄糖、蔗糖、果糖、Ca^(2+)、Mg^(2+)、Zn^(2+)、Fe3+以及多巴胺等有很好的抗干扰能力,加标回收率在96.12%~98.25%之间,可信度较高。Ag@Cu-MOF/GCE操作简单、成本低廉、灵敏度高,在果蔬中VC的快速分析方面潜力巨大。

g-C_(3)N_(4)/壳聚糖复合微球对银离子的吸附性能及其拉曼应用研究

利用壳聚糖的吸附性能和石墨相氮化碳的光催化特性制备了g-C_(3)N_(4)/壳聚糖复合微球,并对银离子进行吸附还原,将所得产物应用于表面增强拉曼(SERS)基底来检测孔雀石绿(MG)。结果表明,制备的复合微球对银离子有较好的吸附容量,可达到152.17 mg/g,吸附银离子后的微球对孔雀石绿的吸附能力降至2%。SERS图谱的特征峰较易分辨,对MG的检测范围为1×10^(-7)~1×10^(-3)mol/L,但复合微球对孔雀石绿的降解能力会影响其长时间的拉曼检测。扫描电镜与能谱分析结果表明,复合微球表面较粗糙,有纳米银生成,分布较为均匀。XPS分析结果表明,复合微球表面主要为单质银。红外光谱分析表明,复合微球没有改变g-C_(3)N_(4)与壳聚糖原有的结构。

NANO碳净化-超高效液相色谱-串联质谱法测定东北黑土壤中多农残含量

本文使用NANO碳净化柱对土壤中的31种农药进行净化,并且通过超高效液相色谱-串联质谱法(UPLC-MS/MS)进行测定。土壤样品经过NANO碳净化柱,净化效果良好。31种农药的检出限为0.001~0.01mg/kg,定量限为0.003~0.033mg/kg,添加回收率在70%~120%之间,相对标准偏差(RSD)在0%~10%之间。结果表明,该方法简单、快捷、灵敏度高,线性范围、回收率和精密度均适合土壤中的31种农药残留检测,在土壤农药残留筛查中具有较好的应用前景。

Preparation of Nano Silver/Silk Fibroin Composite Films

In this study, the outstanding biocompatibility of silk fibroin （SF） and the highly efficient anti-bacterial effect of nano silver （NS） were utilized to prepare SF/NS composite film with anti- bacterial property. The structure and property of the film were characterized. The results showed that the structure of SF in the film was mainly silk I. SF in the film was almost insoluble in water. The tensile strength of film with NS was significantly lower than that of films without NS. When the addition of NS was within the range of 0%-0.6%, the elongation at break had no significant difference. The antibacterial rate of the film on staphylococcus aurens and escherichia coil increased with the amount of NS. The minimum amount of NS in the fdm was O. 1% and the maximum amount was 0.5%.

Preparation of silver nanoparticle via active template under ultrasonic

A novel method was described for the production of silver nanoparticle by using nano-carbon as active template.Special ultrasonic condition was used to assure the active effect of the template and achieve an even and stable micro-reactor system,therefore yield uniform silver nanoparticle without obvious agglomeration.By laser granularity instrument measurement,the silver nanoparticles show a mean diameter of 20.4 nm and narrow distribution between 18.7 nm and 23.0 nm according to the optimum technology.Regular spherical morphology can be observed by transmission electron microscopy(TEM).X-ray diffraction analysis indicates that Ag+ is deoxidized to form metal Ag during producing precursor,subsequent calcinations promote phase transformation from nonholonomic crystal to complete cubic crystal,which is consistent with the standard JCPDS card of silver.The results reveal that the nano-carbon in active template system not only exerts micro-reactor and steric stabilization effect,but also acts as reducing agent during the reaction.