利用产黄青霉培养液的上清液生物合成纳米银影响因素的研究

[目的]对利用产黄青霉培养液的上清液生物合成纳米银的影响因素进行研究。[方法]利用紫外-可见光谱和投射电镜研究硝酸银起始浓度、pH值、光照和微波辐照等条件对合成反应速率及合成纳米银粒径的影响。[结果]硝酸银的最佳起始浓度为2 mmol/L;随着反应体系pH值的升高,反应速率随之加快,合成纳米银粒子的粒径变小;光照和微波辐照均能有效促进纳米银的合成。[结论]该研究为实现纳米银的可控合成提供了试验基础。     

芒果皮提取物合成纳米银及抑菌性研究

以芒果皮提取物作为还原剂,采用生物法合成纳米银粒子。研究了合成过程中pH值、芒果皮提取物添加量和硝酸银浓度对合成粒径和形貌的影响,研究结果通过紫外可见分光光度法、X射线衍射和透射电镜进行了表征。通过表征,分析得到合成的纳米银的粒径介于7～27nm之间,其结晶为立体对称晶体,pH值为11,芒果皮提取物的添加量为0.1mL,硝酸银溶液浓度为0.5mM,反应条件为80℃,水浴15min时,合成的纳米银粒径最小。试验结果表明,生物合成的纳米银粒子的抗菌性良好。     

纳米银灭菌机制及应用研究进展

纳米银作为一种新型材料,在国际上被广泛应用在医学、食品、化工和通讯等领域。纳米银具有其他材料所不具备的优点,其中广谱的抗菌性和病菌对其无耐药性的影响尤为显著。纳米银破坏细菌的细胞壁和细胞膜,进入细菌细胞质后又通过一系列作用来影响细菌代谢和DNA的复制等,最终达到灭菌的效果。对纳米银的灭菌机制和应用进行了综述,阐述纳米银在灭菌过程中的一些作用机制,并对纳米银的抗菌性研究前景进行了展望。     

微生物合成纳米银粒子及抑菌增效作用研究

微生物合成法具有绿色环保、成本低廉、反应条件温和等优点,本研究选用多粘类芽孢杆菌Jaas cd的无细胞滤液胞外合成纳米银粒子,经紫外/可见光分光光度计全波长扫描(UV-vis)、透射电子显微镜扫描(TEM)、X射线粉末衍射分析(XRD)、傅里叶变换红外光谱分析(FT-IR)等方法验证所合成的纳米银粒子粒度在20~50 nm,形态均一,分散性较好。采用菌丝生长速率法研究纳米银与不同杀菌剂复配抑菌效果。结果表明,纳米银与不同杀菌剂复配,对抑制西瓜枯萎病菌GY-16的菌丝生长有显著增效作用。     

纳米银对秸秆腐解过程中元素和成分含量的影响

试验以玉米秸秆为材料,采用静态培养方法,对添加过不同浓度纳米银溶液的玉米秸秆腐解过程中元素和物质成分含量的变化进行了分析,研究纳米银对秸秆腐烂的影响。结果表明,与对照相比,添加纳米银溶液的处理碳元素和木质纤维素含量降低的速率明显减缓,氮元素含量升高速率显著降低,说明纳米银对环境中的微生物具有明显的抑制作用,纳米银在防止秸秆腐烂方面具有重要作用。     

纳米银抗菌剂性能评价和应用现状综述

纳米银是一种新型抗菌剂,具有强大的抑菌和杀菌效果,且抗菌谱广,不会产生耐药性,安全性高,因而将其添加到抗菌塑料制品中形成纳米银塑料,受到越来越广泛的关注。介绍了纳米银抗菌剂的抗菌机理、抗菌优越性和制备方法,阐述了纳米银抗菌剂的性能评价及应用现状,并对纳米银抗菌剂的发展趋势进行了预测,以便为新型塑料制品的研制提供帮助。     

以壳聚糖分子为稳定剂的银纳米颗粒的水热法合成研究

[目的]研究一种以壳聚糖作为还原剂及稳定剂、通过一步水热合成法制备纳米银颗粒的新方法.[方法]用水热法合成以壳聚糖为稳定剂的银纳米颗粒,利用水热法产生的较高温度和较高压力的条件来制备稳定的银纳米颗粒,并考察颗粒的稳定性.[结果]制备的纳米银溶胶具有较好的稳定性,可在室温下长期保存.通过改变反应初始pH值,可调控其大小和形貌.在酸性条件下,测得纳米银颗粒带正电,这非常有利于将其应用在抗菌研究中.[结论]该方法具有环保、简便、产量高等特点,有望应用到以壳聚糖分子为稳定剂的其他金属纳米材料的合成研究中.     

壳寡糖纳米银溶液对烟草花叶病的防治效果及对其化学品质的影响

为了开发一种新型、高效、绿色的烟草花叶病毒抑制剂,利用合成的壳寡糖纳米银溶液进行田间抗烟草花叶病的药效研究,结果表明,壳寡糖纳米银溶液对田间烟草花叶病的预防和治疗的效果最高分别可达67.74%,43.63%;壳寡糖纳米银溶液不仅有效地提高烟叶中性致香成分的含量,还可使烟叶常规化学成分处于较适宜的范围,从而使烟叶的品质得到改善。因此,壳寡糖纳米银溶液对田间感染烟草花叶病的烟株有一定的防治作用。     

纳米银抗菌机理及应用研究进展

纳米银作为一类新型的抗菌材料,具有抗菌高效、广谱和不易产生耐药性等优点,如今已经广泛地运用于各行各业,但纳米银的抗菌机理尚不明确。归纳总结近年来国内外对纳米银抗菌机理的研究进展,分析阐述其应用情况,最后提出需要关注使用纳米银带来的负面环境效应,以利于其更好应用。     

纳米银对烟草病毒的体外抑制作用

为弄清纳米银对烟草病毒病是否具有抑制作用,采用半叶接种法,研究了纳米银对烟草病毒的体外防抑作用.结果表明:微波纳米银对TMV、CMV和PVY 3种单一病毒的体外抑制效果显著,电解纳米银对CMV和PVY的单一病毒的体外抑制效果显著.在3种病毒的复合侵染试验中,微波纳米银对TMV-CMV体外复合侵染的抑制效果显著,电解纳米...     

可视化研究银纳米颗粒与柑橘类农药杀扑磷的相互作用

为检测柑橘类农药杀扑磷,选择具有独特局域表面等离子体共振吸收和散射特性的银纳米。用合成70 nm大小的银纳米颗粒结合Britton-Robinson缓冲溶液研究银纳米与杀扑磷农药的相互作用,发现银纳米颗粒与杀扑磷农药反应形成Ag-S键,检测限达0.2×10~(-6) mol/L,表明用银纳米检测杀扑磷农药是一种成本低、简捷、易操作的好办法,以期为杀扑磷农药的检测提供新的思路和基础。     

Array-based electrical detection of DNA with nanoparticle probes

A DNA array detection method is reported in which the binding of oligonucleotides functionalized with gold nanoparticles leads to conductivity changes associated with target-probe binding events. The binding events localize gold nanoparticles in an electrode gap; silver deposition facilitated by these nanoparticles bridges the gap and leads to readily measurable conductivity changes. An unusual salt concentration-dependent hybridization behavior associated with these nanoparticle probes was exploited to achieve selectivity without a thermal-stringency wash. Using this method, we have detected target DNA at concentrations as low as 500 femtomolar with a point mutation selectivity factor of approximately 100,000:1.     

纳米银对原代培养海马神经细胞凋亡的研究

[目的]探讨纳米银对原代培养海马神经细胞的影响。[方法]用吖啶橙染色观察细胞形态及染色质的变化,用Fluo3荧光染料检测细胞内游离Ca2+浓度变化,并利用ELLSA试剂盒检测Caspase-3凋亡酶活性。[结果]与正常对照组相比,经50μg/ml纳米银处理36h后,海马神经细胞的凋亡率达到最高((48.3±0.33)%),凋亡酶活性增强,并且细胞内游离的Ca2+荧光强度达到41.70±18.78。结论50μg/ml纳米银作用36 h可导致海马神经元凋亡。     

Shape-controlled synthesis of gold and silver nanoparticles

Monodisperse samples of silver nanocubes were synthesized in large quantities by reducing silver nitrate with ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP). These cubes were single crystals and were characterized by a slightly truncated shape bounded by [100], [110], and [111] facets. The presence of PVP and its molar ratio (in terms of repeating unit) relative to silver nitrate both played important roles in determining the geometric shape and size of the product. The silver cubes could serve as sacrificial templates to generate single-crystalline nanoboxes of gold: hollow polyhedra bounded by six [100] and eight [111] facets. Controlling the size, shape, and structure of metal nanoparticles is technologically important because of the strong correlation between these parameters and optical, electrical, and catalytic properties.     

Stepwise evolution of spherical seeds into 20-fold twinned icosahedra

Understanding the factors that influence the growth and final shape of noble metal nanostructures is important for controlling their properties. However, relative to their single-crystalline counterparts, the growth of nanoparticles that contain twin defects can be difficult to control because multiple competitive growth pathways can yield such structures. We used spherical, cubic, and octahedral single-crystalline gold nanoparticles as dual electron microscopy labels and plasmonic seeds to track the growth of multiply twinned silver nanostructures. As the bimetallic nanostructures grew, they successively developed twin planes to ultimately form multiply twinned nanoparticles from single-crystalline seeds. Collectively, these data demonstrate how a series of nanoparticles of different shapes and internal crystal structures are interrelated and develop from one another.     

The effect of silver nanoparticle on Fenugreek seed germination under salinity levels

A study was conducted to evaluate the effect s of silver nanoparticles for ameliorating negative effects of salinity on germination and growth of Fenugreek seeds. In order to investigate salinity stress on Fenugreek germination indices, an experiment was carried out in Iran from October 2014 to November 2014 at Ferdowsi University of Mashhad, in the biotechnology Laboratory, to create salinity stress, sodium chloride (NaCl) at the levels of 0 (as control), 5, 10, 15 and 20 dS/m and Five levels of silver nanoparticles (0, 10, 20, 30 and 40 μg mL^–1) on Fenugreek seed (Trigonella foenum-graecum); were tested Germination characteristics such as total germination (GT), Germination Speed Index (GSI), Shoot and Root of seedling long, Fresh Mass and Dry Mass were measured. Results showed the great effects of silver nanoparticles to improve salinity stress on Fenugreek seed germination. Results showed a significant reduction in germination percent and seedling growth due to the salinity stress while significantly increased with silicon nano-particles application. In without silver nanoparticle low level of salinity (0 dS/m) increased seed germination percentage, while the high levels (5, 10, 15 and 20 dS/m) inhibited the seed germination significantly. The results showed that the effect of AgNPs was significant on germination percentage in P ≤ 0.05. Overall, application of AgNPs was beneficial in improving salinity tolerance in the Fenugreek seedling and its application may stimulate the differences defense mechanisms of plants against salt toxicity.     

Ag修饰Bi2MoO6纳米材料的合成表征及光催化性能研究

以Sn（Ⅱ）为介质,采用原位还原法将Ag纳米粒子负载在Bi2MoO6微球上,通过改变Ag（NH3）2OH原料溶液的体积调控Ag的负载量．结果表明：Ag纳米粒子均匀的分散在Bi2MoO6纳米片表面,未发生明显团聚．该方法制备的Bi2MoO6/Ag纳米异质结催化剂在可见光下具有优异的可见光光催化活性,其原因主要是Ag纳米粒子作为良好的电子受体,可大大降低Bi2MoO6的光生电子空穴的复合概率．