儿茶素-银纳米复合材料的制备及其应用

探索了以植物活性成分儿茶素作为还原剂和保护剂一步水热法合成儿茶素-银纳米复合材料,并进一步测试了纳米复合材料的抑菌活性。 紫外可见吸收光谱(UV-Vis)和红外光谱(FTIR)测定证明制备得到了儿茶素包裹的银纳米粒子。 透射电子显微镜(TEM)和X射线衍射(XRD)结果显示银纳米粒子的平均粒径为22.7 nm,并具有面心立方晶体结构。 抑菌活性实验结果表明,儿茶素-银纳米复合粒子对大肠杆菌、金黄色葡萄球菌以及白色念球菌都有很强抑制作用,尤其对白色念球菌的抑制作用最强,其最低抑制浓度(MIC)和最低杀菌浓度(MBC)分别为19.63和39.26 μg/mL。 儿茶素-银纳米粒子强抑菌活性可归因于其表面银离子的持续释放,有望应用于长效抑菌制剂产品。     

银纳米晶体的制备与表征

在聚乙烯吡咯烷酮存在的条件下,用水合肼还原硝酸银,通过控制反应条件成功制备出了粒径均一、有良好分散性的银纳米微粒,并以此为种子,利用种子诱导生长,在十六烷基三甲基溴化铵的棒状胶束环境中制备出了银纳米棒和纳米线.并用X射线衍射、透射电子显微镜、傅立叶红外光谱和紫外-可见光谱等手段对产品的形貌、结构进行了表征.     

乳液聚合法制备纳米金/聚苯乙烯复合粒子

以氯金酸为前驱体,十二烷基硫醇和硼氢化钠分别作为稳定剂和还原剂,采用相转移法制备了单分散的金纳米粒子.将金纳米粒子通过乳液聚合的方法制备了纳米金/聚苯乙烯复合粒子.通过紫外-可见吸收光谱(UV-Vis)研究了纳米金和纳米金/聚苯乙烯复合粒子的光吸收特性,使用傅立叶变换红外光谱(FT-IR)、X射线衍射(XRD)、透射电子显微镜(TEM)和动态光散射(DLS)对产物的组成、晶体结构、形貌、以及粒径进行了表征.结果表明,复合粒子为粒径分布较窄的球形,其中的金纳米粒子为面心立方结构.热失重分析(TGA)说明制备的纳米金/聚苯乙烯复合粒子具有很好的热稳定性.     

盐酸羟胺络合法制备银溶胶及表面增强拉曼基底

报道了一种制备银溶胶的新方法.用紫外-可见光谱和透射电镜研究了银纳米粒子的形成过程、粒子形状及粒径分布.紫外光谱结果表明,在还原剂中加入碘化银溶胶后立即形成银纳米粒子,开始时粒子的粒径较小,很快聚集成较大的粒子.随着反应的进行,较大的粒子又逐渐碎裂为较小的粒子.同时,粒子的粒径分布逐渐变窄,说明银纳米粒子的形成过程也是粒子粒径均化的过程.透射电镜的研究结果表明,银纳米粒子为形状均一的球形,平均粒径约35nm.将这种银纳米粒子转移到固体基片上可得到活性较高的表面增强拉曼(SERS)基底.     

利用还原性多糖合成银纳米粒子

利用还原性多糖为稳定剂、AgNO₃为前驱物, 通过一条绿色途径合成银纳米粒子, 并探讨了纳米粒子的形成机理. 对多糖高浓度时制得的复合物在空气与氮气气氛下进行了热处理, 分别得到了银的大孔海绵体与银纳米粒子/碳的复合材料. 对产物进行了X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外-可见分光光度(UV-vis)以及BET吸附表征.     

ZnO/Ag复合纳米粒子的制备与表征

以乙酸锌为前驱物,乙醇为溶剂,油酸钠为表面修饰剂,采用溶液化学法,在乙醇体系中制得纳米Zn O。然后缓慢加入一定量的硝酸银乙醇溶液,在乙醇的还原作用下将Ag+还原为Ag纳米粒子,制得Zn O/Ag复合纳米粒子。通过紫外-可见吸收光谱(UV-Vis)、荧光光谱(FL)、透射电子显微镜(TEM)和X射线衍射(XRD)等方法对所制备的氧化锌-银复合纳米粒子样品进行表征。结果表明,所合成的Zn O/Ag复合纳米粒子为球形,尺寸为20-30nm且粒径分布较窄。Ag纳米粒子附着于Zn O纳米粒子表面,并起到良好的表面修饰作用。对制备Zn O/Ag复合纳米粒子的机理进行了初步探究。     

氨水共沉淀法制备Nd∶Y2O3透明陶瓷纳米粉体

以Y2O3粗粉、Nd2O3、硝酸和氨水为原料,通过共沉淀法制备了Nd∶Y2O3透明陶瓷纳米粉体,利用热重/差热分析（TG/DTA）、红外光谱（FTIR）、粉末X射线衍射（XRD）、透射电镜（TEM）以及能谱分析（EDS）等方法对合成的Nd∶Y2O3纳米粉体进行了表征。结果表明,在前驱物中添加适量SO4^2-离子能减轻煅烧得到的Nd∶Y2O3纳米粉体粒子的团聚,使Nd∶Y2O3纳米粒子的粒度均匀并呈球形分布。在600～1000℃煅烧3 h所得粉体粒子的粒径在20～40 nm之间,具有较好的分散性。     

超小金纳米簇用于荧光及CT双模态成像的研究

基于金纳米簇强烈的量子限制效应（strong quantum confinement effect,SQCE）,采用一步合成法,制备了同时具有高效近红外荧光与CT双模态成像能力的超小金纳米簇.实验表明,通过优化合成比例以及合成条件,所合成的超小金纳米簇具有很大的斯托克斯（Stokes）位移、较高的荧光强度和X射线吸收效率.除此之外,该超小金纳米簇具有良好的单分散性、稳定性和生物相容性.4T1肿瘤细胞荧光成像实验结果表明,该纳米粒子可被肿瘤细胞快速、高效地摄取.     

银纳米粒子-介孔菱沸石-无纺布复合材料的构建及其止血和抗菌性能分析

以无纺布(NW)为基质,采用原位生长法制备了介孔菱沸石-无纺布(mCHA-NW),再以其为载体,复合银纳米粒子(AgNPs),最终得到银纳米粒子-介孔菱沸石-无纺布(AgNPs-mCHA-NW)复合材料.利用X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)、X射线光电子能谱仪(XPS)、全自动物理吸附仪(BE...     

同轴静电纺丝法在纳米中空TiO2纤维中填充Ag的应用

以聚乙烯吡咯烷酮（PVP）溶胶/钛酸四正丁酯和PVP溶胶/银颗粒为前驱体,以共轴静电纺丝法制备了银填充的TiO2中空纳米纤维.将双组分纤维在200℃下热处理去除乙醇与表面吸附水后,继而在空气气氛中焙烧至600℃,可以得到在内表面上沉积银颗粒的TiO2纳米管,银颗粒的直径为5-40nm,TiO2纳米管的外径150-300nm,管臂厚10-20nm.用红外吸收光谱（IR）、X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）等测试手段对超细纤维进行了表征.中空纤维的直径和管壁可以通过改变电纺参数来调节.与Ag-TiO2纳米纤维、TiO2纳米中空纤维、TiO2纳米纤维及TiO2纳米粉体相比较,Ag颗粒填充的TiO2纳米中空纤维在光分解亚甲基蓝上表现出了更好的光催化性能.     

An Evaluation of Antimicrobial,Anticancer, Anti-Inflammatory and Antioxidant Activities of Silver Nanoparticles Synthesized from Leaf Extract of Madhuca longifolia Utilizing Quantitative and Qualitative Methods

In the current decade, nanoparticles are synthesized using solvents that are environmentally friendly. A number of nanoparticles have been synthesized at room temperature using water as a solvent, such as gold (Au) and silver (Ag) nanoparticles. As part of nanotechnology, nanoparticles are synthesized through biological processes. Biological methods are the preferred method for the synthesis of inorganic nanoparticles (AgNPs) as a result of their simple and non-hazardous nature. Nanoparticles of silver are used in a variety of applications, including catalysts, spectrally selective coatings for solar absorption, optical objectives, pharmaceutical constituents, and chemical and biological sensing. Antimicrobial agents are among the top uses of silver nanoparticles. In the current study, silver nanoparticles were biologically manufactured through Madhuca longifolia, and their antibacterial activity against pathogenic microorganisms, anticancer, anti-inflammatory, and antioxidant activities were assessed. UV-Vis spectroscopy, XRD (X-ray diffraction), transmission electron microscopy, Zeta Potential, and FTIR were used to characterize silver nanoparticles. The current work describes a cheap and environmentally friendly method to synthesize silver nanoparticles from silver nitrate solution by using plant crude extract as a reducing agent.     

Facile Biogenic Synthesis and Characterization of Seven Metal-Based Nanoparticles Conjugated with Phytochemical Bioactives Using Fragaria ananassa Leaf Extract

In this investigation, for the first time, we used Fragaria ananassa (strawberry) leaf extract as a source of natural reducing, capping or stabilizing agents to develop an eco-friendly, cost-effective and safe process for the biosynthesis of metal-based nanoparticles including silver, copper, iron, zinc and magnesium oxide. Calcinated and non-calcinated zinc oxide nanoparticles also synthesized during a method different from our previous study. To confirm the successful formation of nanoparticles, different characterization techniques applied. UV-Vis spectroscopy, X-ray Diffraction (XRD) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS), Photon Cross-Correlation Spectroscopy (PCCS) and Fourier Transformed Infrared Spectroscopy (FT-IR) were used to study the unique structure and properties of biosynthesized nanoparticles. The results show the successful formation of metal-based particles in the range of nanometer, confirmed by different characterization techniques. Finally, the presented approach has been demonstrated to be effective in the biosynthesis of metal and metal oxide nanoparticles.     

SPEEK/PVA-AgNPs复合膜的制备与表征

首先,以磺化聚醚醚酮(SPEEK)为光敏自由基载体,以聚乙烯醇(PVA)为分散稳定剂,制备了具有光生自由基功能的SPEEK/PVA高分子膜;然后,通过在SPEEK/PVA膜上紫外光诱导Ag+还原生成纳米银颗粒(AgNPs),从而得到SPEEK/PVA-AgNPs复合膜。采用紫外可见分光光度计(UV-Vis)、扫描电镜(SEM)、能谱仪(EDS)、X射线光电子能谱分析(XPS)及傅里叶变换红外光谱(FT-IR)等手段对SPEEK/PVA-AgNPs材料进行了表征。结果显示:生成的银颗粒为纳米级,较均匀地分布在SPEEK/PVA高分子膜表面,SPEEK/PVA-AgNPs复合膜整体呈现棕色;形成的银纳米颗粒具有较完整的晶型,且价态分析显示其为单质。     

Phyto-Extract-Mediated Synthesis of Silver Nanoparticles Using Aqueous Extract of Sanvitalia procumbens,and Characterization,Optimization and Photocatalytic Degradation of Azo Dyes Orange G and Direct Blue-15

Green synthesis of silver nanoparticles (AgNPs) employing an aqueous plant extract has emerged as a viable eco-friendly method. The aim of the study was to synthesize AgNPs by using plant extract of Sanvitalia procumbens (creeping zinnia) in which the phytochemicals present in plant extract act as a stabilizing and reducing agent. For the stability of the synthesized AgNPs, different parameters like AgNO₃ concentration, volume ratios of AgNO₃, temperature, pH, and contact time were studied. Further, AgNPs were characterized by UV–visible spectroscopy, FT-IR (Fourier Transform Infrared Spectroscopy), XRD (X-ray Diffraction), SEM (Scanning Electron Microscopy), and EDX (Energy Dispersive X-ray Spectrometer) analysis. FT-IR analysis showed that the plant extract contained essential functional groups like O–H stretching of carboxylic acid, N–H stretching of secondary amides, and C–N stretching of aromatic amines, and C–O indicates the vibration of alcohol, ester, and carboxylic acid that facilitated in the green synthesis of AgNPs. The crystalline nature of synthesized AgNPs was confirmed by XRD, while the elemental composition of AgNPs was detected by energy dispersive X-ray analysis (EDX). SEM studies showed the mean particle diameter of silver nanoparticles. The synthesized AgNPs were used for photocatalytic degradation of Orange G and Direct blue-15 (OG and DB-15), which were analyzed by UV-visible spectroscopy. Maximum degradation percentage of OG and DB-15 azo dyes was observed, without any significant silver leaching, thereby signifying notable photocatalytic properties of AgNPs.     

Microwave-Assisted Green Synthesis of Non-Cytotoxic Silver Nanoparticles Using the Aqueous Extract of Rosa santana (rose) Petals and Their Antimicrobial Activity

Green methods using biological extracts, in particular plant-based solutions, have shown great potential for silver nanoparticle synthesis. A microwave-assisted single-step phytosynthesis of silver nanoparticles is described in the present study. The aqueous extract obtained from the Rosa santana (rose) petals was used for the first time in the synthesis. The synthesized nanoparticles obtained after optimized microwave conditions for time and temperature were analyzed by ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Zeta-size analysis. The results obtained from the characterization studies showed that the synthesized nanoparticles were nearly spherical in shape with sizes from 6.52?nm to 25.24?nm with an average particle size of 14.48?nm with a face-centered cubic structure. The antibacterial activities of the synthesized nanoparticles were evaluated and revealed that the silver nanoparticles displayed good inhibition against both Gram-negative and Gram-positive bacteria. Also, the cytotoxic effect of the silver nanoparticles on a mouse fibroblast cell line (L929) was studied by a cell viability assay. The results showed that phytosynthesized silver nanoparticles were nontoxic to the healthy normal cell line at all tested concentrations.     

Biosynthesis of silver nanoparticles using Onosma sericeum Willd. and evaluation of their catalytic properties and antibacterial and cytotoxic activity

In this study, silver nanoparticle (AgNP) synthesis was carried out using Onosma sericeum Willd. aqueous extract for the first time, with a simple, economical, and green method without the need for any other organic solvent or external reducing or stabilizing agent. A variety of AgNPs, all of different particle sizes, were synthesized by controlling the silver ion concentration, extract volume, temperature, and pH. It was determined that the optimum conditions for AgNP synthesis were 1 mM AgNO3, pH 8, 25 °C, 20 g/200 mL extract, silver nitrate, and extract ratio 5:1 (v/v). The AgNPs were defined using UV-Vis spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The particle size distribution and zeta potential measurements of the AgNPs were measured using the dynamic light scattering (DLS) technique. It was determined that the AgNPs with a particle size of less than 10 nm showed a higher catalytic effect in the reduction of 2-nitrobenzenamine. It was also found that these nanoparticles had a cytotoxic effect on the MCF-7 breast cancer cell line depending on dosage and time. The resulting IC50 values were between 76.63 µg/mL and 169.77 µg/mL. Furthermore, the biosynthesized AgNPs showed effective antibacterial activity against the Acinetobacter baumannii bacteria. The results of the study showed that synthesized AgNPs can have a promising role in biomedical and nanobiotechnology applications.     

In Situ Formation of a Uniform Distribution of Silver Nanoparticles in PVDF: Kinetics of Formation and Resulting Properties

Hybrid organic/silver nanoparticle thermoplastic films have been prepared using a single step process where the silver nanoparticles were formed during a cure cycle applied to the film. Figure 1 is a TEM demonstrating the ability of our technique to produce silver nanoparticles in the semi-crystalline polymer Poly(vinylidene fluoride) (PVDF). The current laboratory focus is on characterizing kinetics and particularly the diameter growth and inter-particle distance as a function of time and temperature using the techniques of small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). Using the Beaucage model, the SAXS data demonstrates that the particle size reaches equilibrium after approximately 70 minutes of curing at 240 °C. This result is also observed in the XRD results where the half width of the diffraction peaks becomes smaller quickly during the initial hour. In a parallel experiment using DSC, the exothermic heat flow increases rapidly during the first hour but does not reach completion until almost 150 minutes.     

可控纳米银胶体的稳定性

纳米银胶体(AgNPs)长期储存不稳定性问题是本研究的中心,着重考察了不同前驱体对纳米银胶体的稳定性影响。分别以银氨([Ag(NH3)2]OH)溶液和Ag NO3溶液为前驱体制备了多份纳米银胶体样品并通过UV-Vis、FE-SEM、EDS、ZETA电位仪等现代分析测试手段研究了纳米银胶的形貌、粒径大小以及稳定性。对比分析发现,以[Ag(NH3)2]OH溶液为前驱体,制备的纳米银胶体具有粒径可控,尺寸均一,分散性良好等特点;而且经过一个月的常温储存,表现出比用Ag NO3溶液为前驱体制备的纳米银胶体具有更高的储存稳定性。     

可控纳米银胶体的稳定性研究

纳米银胶体(AgNPs)长期储存不稳定性问题是本研究的中心,着重考察了不同前驱体对纳米银胶体的稳定性影响.分别以银氨([Ag(NH₃)₂]OH)溶液和AgNO₃溶液为前驱体制备了多份纳米银胶体样品并通过UV-Vis、FE-SEM、EDS、ZETA电位仪等现代分析测试手段研究了纳米银胶的形貌、粒径大小以及稳定性.对比分析发现,以[Ag(NH₃)₂]OH溶液为前驱体,制备的纳米银胶体具有粒径可控,尺寸均一,分散性良好等特点;而且经过一个月的常温储存,表现出比用AgNO₃溶液为前驱体制备的纳米银胶体具有更高的储存稳定性.     

Phyto-Functionalized Silver Nanoparticles Derived from Conifer Bark Extracts and Evaluation of Their Antimicrobial and Cytogenotoxic Effects

Silver nanoparticles synthesized using plant extracts as reducing and capping agents showed various biological activities. In the present study, colloidal silver nanoparticle solutions were produced from the aqueous extracts of Picea abies and Pinus nigra bark. The phenolic profile of bark extracts was analyzed by liquid chromatography coupled to mass spectrometry. The synthesis of silver nanoparticles was monitored using UV-Vis spectroscopy by measuring the Surface Plasmon Resonance band. Silver nanoparticles were characterized by attenuated total reflection Fourier transform infrared spectroscopy, Raman spectroscopy, dynamic light scattering, scanning electron microscopy, energy dispersive X-ray and transmission electron microscopy analyses. The antimicrobial and cytogenotoxic effects of silver nanoparticles were evaluated by disk diffusion and Allium cepa assays, respectively. Picea abies and Pinus nigra bark extract derived silver nanoparticles were spherical (mean hydrodynamic diameters of 78.48 and 77.66 nm, respectively) and well dispersed, having a narrow particle size distribution (polydispersity index values of 0.334 and 0.224, respectively) and good stability (zeta potential values of −10.8 and −14.6 mV, respectively). Silver nanoparticles showed stronger antibacterial, antifungal, and antimitotic effects than the bark extracts used for their synthesis. Silver nanoparticles obtained in the present study are promising candidates for the development of novel formulations with various therapeutic applications.