纳米银/P(AAEM-St)复合材料的原位超声合成与表征

超声原位引发乙酰乙酸基甲基丙烯酸乙酯(AAEM)与苯乙烯(St)聚合,制备纳米银/P(AAEM-St)复合粒子。UV-Vis和XRD结果证明了纳米银粒子且其具有面心立方结构。TEM结果表明纳米银粒径在10～30 nm,且较均匀的分散在聚合物基体中。     

基于植物质还原的银纳米颗粒的制备及在织物抗菌整理上的应用

纳米银是以纳米技术为基础研制而成的新型抗菌产品,由于量子效应和尺寸效应具有普通银系抗菌剂无法比拟的抗菌效果。本研究以黄芩、丁香、洋浦桃、芳樟4种植物质提取液制备银纳米颗粒,并借助于UV-Vis、TEM以及XRD对产物进行表征,结果表明增加植物质提取液浓度或增大NaOH加入量,均有利于制得粒径较小的银纳米颗粒。SEM图片表明采用浸渍法可将所得纳米银颗粒负载于纯棉织物上,通过考察浸渍时间、温度、浴比对织物上载银量的影响,确定较优的浸渍条件为时间30 h,温度55℃,浴比为1:25。分别考察了银纳米颗粒粒径和植物质种类对所得载银织物抗菌性能的影响,发现负载到织物上的纳米银粒径越小,织物抑菌效果越好;利用本身具有抑菌效果的黄芩、丁香来制备银纳米颗粒,有利于增强所得载银织物的整体抗菌性能;4种植物质中以黄芩制得的载银织物抗菌效果最优,对金黄色葡萄球菌、大肠杆菌等实验菌株均有强烈的抑制作用。     

载银硅藻土/PNAC复合凝胶制备及性能

以N,N-二甲基甲酰胺(DMF)为还原剂,聚乙烯吡咯烷酮(PVP)为分散剂制备纳米银,并将其负载于改性硅藻土;以N-异丙基丙烯酰胺、丙烯酸为单体,N,N-亚甲基双丙烯酰胺为交联剂,通过自由基聚合法与载银硅藻土合成载银硅藻土/PNAC复合凝胶。利用紫外可见分光光度计、傅里叶变换红外光谱(FTIR)和扫描电镜(SEM)分别对纳米银、复合凝胶和载银硅藻土进行表征,并对复合凝胶的pH值、温度响应性和抗菌性进行测定。扫描电镜结果表明合成的纳米银粒径为(75±10) nm,且纳米银负载于改性硅藻土表面孔洞中; FTIR表明复合凝胶制备成功;抑菌实验表明,复合凝胶能够持续缓释纳米银产生抑菌效果,对大肠杆菌的抑菌性优于金黄色葡萄球菌。     

化学还原法合成Cu纳米粒子分析

通过在室温下化学还原以简单的途径合成了铜纳米粒子,分别用硼氢化钠和聚乙烯吡咯烷酮还原并稳定了Cu~(2+)离子。评估了还原剂/前体盐(RA/PS)比的变化对CuNPs尺寸和形态的影响。合成材料通过紫外可见(UV-Vis)光谱,X射线衍射(XRD),扫描电子显微镜(SEM)和透射电子显微镜(TEM)。UV-Vis光谱显示在569nm处有一个CuNPs等离子体激元峰,在485nm处有另一个Cu_2O峰。XRD分析表明,fcc-Cu相含有少量的fcc-Cu_2O化合物。SEM和TEM研究表明,当RA/PS比值是2.6的时候,获得的粒径大概是7nm半球形CuNPs,得到较大粒径多面体形Cu_2O颗粒,最大的粒径为150nm。除此以外,于RA/PS比是1.66的时候,获得在其尖端具备量子限域效应的星形Cu_2O粒子。     

聚多巴胺功能化纳米银粒子制备及抗菌性能研究

采用一步法,以聚多巴胺(PDA)为还原剂和保护剂,制备PDA功能化的纳米银粒子(PDA-nanoAg)。提出PDA-nanoAg合成机理,并考察其在水相中的分散稳定性。通过紫外-可见吸收分光光度计(UV-Vis)、透射电子显微镜(TEM)、傅里叶变换红外光谱仪(FTIR)对产物形貌和结构进行表征。采用肉汤稀释法测试PDAnanoAg的抗菌性能。结果表明,所制备的PDA-nanoAg平均粒径为50 nm,具有良好的稳定分散性;对埃希氏大肠杆菌(E.coli)、金黄色葡萄球菌(S.aureus)的最小抑菌浓度(MIC)为7.56 mg/L,最小杀菌浓度(MBC)为30.24mg/L。     

聚多巴胺功能化纳米银粒子制备及抗菌性能

采用一步法,以聚多巴胺(PDA)为还原剂和保护剂,制备PDA功能化的纳米银粒子(PDA-nanoAg)。提出PDA-nanoAg合成机理,并考察其在水相中的分散稳定性。通过紫外-可见吸收分光光度计(UV-Vis)、透射电子显微镜(TEM)、傅里叶变换红外光谱仪(FTIR)对产物形貌和结构进行表征。采用肉汤稀释法测试PDAnanoAg的抗菌性能。结果表明,所制备的PDA-nanoAg平均粒径为50 nm,具有良好的稳定分散性;对埃希氏大肠杆菌(E.coli)、金黄色葡萄球菌(S.aureus)的最小抑菌浓度(MIC)为7.56 mg/L,最小杀菌浓度(MBC)为30.24mg/L。     

等离子体法制备碳纳米管负载银粒子及抑菌性研究

通过温和的等离子体法制备出碳纳米管负载纳米银粒子,并研究了其对大肠杆菌的抑制作用。首先用氧等离子体处理碳纳米管,再将银离子负载在碳纳米管表面上,接着用氢等离子体将负载的银离子还原成纳米银粒子。用TEM和XRD对制备出的银粒子进行表征,研究表明,平均粒径为5nm左右的银粒子负载在碳纳米管表面。对大肠杆菌的抑菌实验表明,Ag-CNTs浓度大于1μg/mL时,对大肠杆菌生长抑制效果明显。     

液相化学还原法制备单分散的纳米银粒子

以月桂酸为修饰剂,水合肼为还原剂,银氨溶液为银源,在水相中利用液相化学还原法制备了单分散的粒径分布均匀的纳米银粒子。利用透射电子显微镜(TEM)、X射线衍射(XRD)对样品的形貌和结构进行了分析,研究表明,修饰剂与硝酸银的质量比、反应温度对纳米银形貌及粒径有很大影响。当修饰剂与硝酸银的质量比为1.2∶1、反应温度为室温时,能够制备平均粒径为8 nm、粒径均匀、单分散的纳米银粒子。另外,UV光谱也证实,所制的溶胶为粒径均匀的纳米银溶胶。     

反相微乳液制备AgCl/PMMA复合胶乳及其抗菌性能

以聚乙二醇辛基苯基醚(OP)为表面活性剂,甲基丙烯酸甲酯(MMA)为油相构筑的反相微乳液合成纳米Ag Cl粒子,然后通过微乳液聚合制备Ag Cl/PMMA复合胶乳。利用紫外-可见吸收光谱(UV-vis)和透射电镜(TEM)研究微乳液中表面活性剂浓度(cop)、水相中盐浓度(csalt)对纳米Ag Cl粒子的形成及形貌影响,结果发现合成的Ag Cl粒子近似球状,粒径在5 nm左右;在反相微乳液中随cop、csalt的增加,形成的纳米Ag Cl粒子数增多、平均粒径有所减小。Ag Cl/PMMA复合胶乳对大肠杆菌表现出明显的抗菌活性。通过反相微乳液及其聚合技术制备包含有纳米Ag Cl的复合胶乳,方法简便、易于放大,所制备的Ag Cl/PMMA复合胶乳作为抗菌剂具有良好的应用前景。     

COS-g-PEI修饰纳米银粒子的制备及其抗菌性

首先以离子液体1-丁基-3-甲基咪唑氯盐([BMIM]Cl)为反应介质和催化剂,羰基二咪唑为偶联剂,均相合成了壳寡糖接枝聚乙烯亚胺共聚物(COS-g-PEI);其次,以COS-g-PEI为稳定剂,硝酸银为前驱体,硼氢化钠为还原剂,采用原位还原法制备了COS-g-PEI修饰纳米银复合粒子(Ag NPs@-COS-g-PEI)。采用IR、~1HNMR对聚合物结构进行表征,结果证实成功合成了COS-g-PEI接枝共聚物;UV-Vis、TEM结果表明,成功制备了稳定的Ag NPs@-COS-g-PEI复合粒子。通过滤纸片法和牛津杯法测试了COS-g-PEI及Ag NPs@-COS-g-PEI对金黄色葡萄球菌和大肠杆菌的抗菌性能,Ag NPs@-COS-g-PEI的抑菌圈直径均比COS-g-PEI大,结果表明,Ag NPs与COS-gPEI有机结合大大提高了抗菌性能。     

Mangrove-mediated synthesis of silver nanoparticles using native Avicennia marina plant extract from southern Iran

The development of eco-friendly and nontoxic processes for the synthesis of nanoparticles is one of the most important discussed issues in nanotechnology science. This study reports the green synthesis of silver nanoparticles (AgNPs) using aqueous extract of leaf, stem, and root of Avicennia marina, the native and dominant mangrove plant in southern Iran. Among the different plant parts, the extract of leaves yielded the maximum synthesis of AgNPs. Synthesized AgNPs were investigated using UV–visible spectrophotometry, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and Fourier transform infrared (FTIR) spectroscopy. Absorption spectrum in 420?nm confirmed the synthesis of AgNPs. TEM images revealed that the synthesized AgNPs had the same spherical morphology with a size range between 0 and 75?nm. The distribution size histogram indicated that the most frequent particles were in the range of 10–15?nm and the mean size of nanoparticles was 17.30?nm. The results of SEM image showed nanoparticles with a size range between 15 and 43?nm. XRD pattern indicated the crystalline nature of synthesized nanoparticles. EDS results confirmed the presence of elements like silver, carbon, chlorine, nitrogen, and oxygen in the nanoparticles produced from leaf extract. Silver had the maximum percentage of formation, 51.6%. FTIR indicated the presence of different functional groups such as amines, alcohol, alkanes, phenol, alkyl halides, and aromatic loops in the synthesis process. Green biosynthesis of AgNPs using aqueous extract of native A. marina appears rapid, reliable, nontoxic, and eco-friendly.     

Ag NPs改性鱼鳞明胶-琼脂复合膜的制备及性能表征

利用鱼鳞明胶作为还原剂和稳定剂制备银纳米颗粒（silver nanoparticles, Ag NPs），研究Ag NPs添加量（0.04wt%-0.2wt%）对鱼鳞明胶-琼脂复合膜的理化性能和抗菌性能的影响。通过透射电子显微镜和X射线粉末衍射对合成的Ag NPs进行表征，结果表明制得Ag NPs为球形形貌，平均粒径为9.3 ?1.8 nm。随着Ag NPs添加量的增加，鱼鳞明胶-琼脂复合膜的色泽变黄渐深，透明度下降，对紫外和可见光的吸收增强，同时，复合膜的断裂延展性、水蒸气阻隔性能和耐水性能显著增强，而厚度和抗拉强度却无明显变化。FTIR和热重分析结果表明，Ag NPs与膜基质间存在化学相互作用，并在一定程度上改善了复合膜的热稳定性。抑菌环实验结果显示，复合膜可以在0.04wt%-0.2wt%较低的银浓度下实现良好的抗菌效果。研究结果将为鱼鳞明胶可降解抗菌包装材料的开发提供新思路。     

中草药还原法制备银纳米颗粒及其抗菌性能表征

分别以中草药丁香、山茱萸、地榆和乌梅的提取液为还原剂和保护剂合成银纳米颗粒,利用紫外-可见吸收光谱(UV-vis)、透射电镜(TEM)以及X射线粉末衍射(XRD)对产物进行了表征。结果表明,所得银纳米颗粒呈近球形,提高提取液的pH有利于获得粒径较小、分散性好、稳定性高的银纳米颗粒。进一步考察制得的银纳米颗粒的抗菌性能,结果表明,其对大肠杆菌和金黄色葡萄球菌有很强的抑制作用,最小抑菌质量浓度(M IC)分别可达1.69和3.38 mg/L。     

Study on antibacterial activity of silver nanoparticles synthesized by gamma irradiation method using different stabilizers

Colloidal solutions of silver nanoparticles (AgNPs) were synthesized by gamma Co-60 irradiation using different stabilizers, namely polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin. The particle size measured from TEM images was 4.3, 6.1, 7.6, and 10.2 nm for AgNPs/PVP, AgNPs/PVA, AgNPs/alginate, and AgNPs/sericin, respectively. The influence of different stabilizers on the antibacterial activity of AgNPs was investigated. Results showed that AgNPs/alginate exhibited the highest antibacterial activity against Escherichia coli (E. coli) among the as-synthesized AgNPs. Handwash solution has been prepared using Na lauryl sulfate as surfactant, hydroxyethyl cellulose as binder, and 15 mg/L of AgNPs/alginate as antimicrobial agent. The obtained results on the antibacterial test of handwash for the dilution to 3 mg AgNPs/L showed that the antibacterial efficiency against E. coli was of 74.6%, 89.8%, and 99.0% for the contacted time of 1, 3, and 5 min, respectively. Thus, due to the biocompatibility of alginate extracted from seaweed and highly antimicrobial activity of AgNPs synthesized by gamma Co-60 irradiation, AgNPs/alginate is promising to use as an antimicrobial agent in biomedicine, cosmetic, and in other fields.     

Antibacterial activity of silver nanoparticles prepared by a chemical reduction method

Silver nanoparticles were obtained by chemical reduction of silver nitrate in water with sodium borohydride (NaBH₄) in the presence of SDS (sodium dodecyl sulfate) as a stabilizer. The synthesized silver nanoparticles were characterized by UV-vis spectroscopy (UV-vis) and transmission electron microscopy (TEM). The formation of silver nanoparticles was confirmed from the appearance of surface plasmon absorption maxima at 400 nm by UV-vis. TEM showed the spherical nanoparticles with size in 10–20 nm. The antibacterial activity of silver nanoparticles was tested by using Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coil (E. coli). The silver nanoparticles, whose bacterial activity was dependent on the aggregation degree between particles, exhibited bacterial activity against S. aureus and E. coli.     

Rapid biological synthesis of silver nanoparticles using Kalopanax pictus plant extract and their antimicrobial activity

Silver nanoparticles (AgNPs) have promising potential in biomedicine, energy science, optics, and health care applications. We synthesized AgNPs using plant, Kalopanax pictus leaf extract. UV-visible spectrophotometric study showed the characteristic peak for AgNPs at wavelength 430 nm. The optical density at 430 nm increased after addition of plant leaf extract, indicating increase in formation of nanoparticles. Comparative time course analyses for AgNP synthesis carried out at different reaction temperatures (20, 60, and 90 °C) revealed higher reaction rate for K. pictus than Magnolia kobus plant leaf extract, which showed highest AgNP synthesis rate in the previous report. Electron microscopy analyses confirmed the presence of well dispersed AgNPs, predominantly with spherical shapes. In transmission electron microscopy, the particle size decreased with increase in temperature. Electron dispersive X-ray spectroscopy analyses indicated that Ag content increased with increase in reaction temperature. Fourier transform-infrared spectroscopy studies revealed capping of bioorganics from plant to the synthesized AgNPs. The antimicrobial activity of the synthesized AgNPs against Escherichia coli increased with increase in reaction temperature. The observations in this study will prove beneficial in approaching rapid synthesis of AgNPs and their antimicrobial application.     

Plant mediated green synthesis and antibacterial activity of silver nanoparticles using Crataegus douglasii fruit extract

In this study, silver nanoparticles were synthesized using the Crataegus douglasii fruit extract as a reducing agent. The reaction process was monitored by UV–vis spectroscopy. Further characterization was carried out using scanning electron microscopy (SEM). To optimize the biosynthesis of silver nanoparticles, the effect of process variables such as extract concentrations, mixing ratio of the reactants, time and pH were also investigated. The SEM images showed silver nanoparticles with 29.28 nm size and nearly spherical shape at 24 h interaction time. The antibacterial activity of the synthesized silver nanoparticles was confirmed against Staphylococcus aureus and Escherichia coli.     

Systemic Evaluation of Mechanism of Cytotoxicity in Human Colon Cancer HCT-116 Cells of Silver Nanoparticles Synthesized Using Marine Algae Ulva lactuca Extract

In the current study, biogenic silver nanoparticles (U-AgNPs) were synthesized using marine green macro-algal Ulva lactuca extract, and evaluated mechanism behind its anticancer activity against the Human colon cancer (HCT-116). The biogenic U-AgNPs were characterized using various physiochemical techniques. The TEM micrographs confirmed the spherical morphology of synthesized U-AgNPs, with a mean size of 8–14 nm. EDX spectrum as well as ICP-OES confirmed that AgNPs was nearly 90% purity for silver. FTIR Spectra analysis of U-AgNPs confirmed U. lactuca extract bioactive molecules presence over U-AgNPs surface as a stabilizing agent, thereby improving biocompatibility. The cytotoxicity study revealed the dose dependent cell death in colon cancer cells with no loss of viability in normal human colon epithelial cells. Furthermore, the fluorescence micrographs of nucleus staining assay revealed the DNA fragmentation and nucleus condensation of cancer cells treated with U-AgNPs, indicating an apoptosis-mediated cell death. The western bolt and RT-PCR analysis of U-AgNPs treated cancer cells showed the rise in proapoptotic markers (P53, Bax, and P21) and decline in anti-apoptotic markers (Bcl-2), thus confirming the p53-dependent apoptosis mediated cell death in HCT-116. Overall, our study concluded that novel biogenic U-AgNPs nanoparticles, synthesized using marine green macro-algal U. lactuca extract showed efficient anticancer activity against HCT-116 cell line and hence could work as potential therapeutic agent for targeted anti-cancer therapy.