纳米银标记物的制备及其在生物分析中的应用

纳米银是一种具有良好生物兼容性并有独特的光学及催化特性的纳米材料,且适合于多种检测方法,是一种极有潜力的生物探针的材料。本文主要综述了用于生物标记的纳米银的合成方法、表征手段及其表面的修饰、并介绍了其作为生物分子标记物的应用状况。     

石墨烯负载纳米银的制备及其对H2O2的电化学检测

采用改进的Hummers法制备了氧化石墨烯（GO）,然后以水合肼作为还原剂,并控制反应的pH=10来制备还原氧化石墨烯（RGO）。采用化学还原法,以石墨烯为载体,以乙酰丙酮银为前体,以硼氢化锂四氢呋喃溶液为还原剂将银离子还原,制备了石墨烯负载纳米银复合材料。通过X 射线粉末衍射（XRD）、傅里叶变换红外光谱（FTIR）和透射电子显微镜（TEM）等表征方法证明了石墨烯上负载的银纳米颗粒结晶良好、尺寸均一、分布均匀,其中银纳米颗粒直径约为8nm。通过循环伏安和计时电流技术对石墨烯负载纳米银复合材料进行电化学测试,结果表明,石墨烯负载纳米银复合材料对过氧化氢的还原具有良好的电催化活性。以此复合纳米结构构建的过氧化氢传感器测试过氧化氢浓度的线性范围为0.1～62.3mmol/L（R=0.990）,检出限为0.017mmol/L（S/N=3）,响应时间小于2s。     

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。     

单分散胶体颗粒的有序组装及其应用研究进展

本文综述了近1～2年来课题组在单分散胶体微球有序组装及其应用方面的研究进展.其中包括250～1300 nm宽尺寸范围单分散二氧化硅胶体微球的重力沉降自组织;旨在提高光子晶体折射率反差的TiO2/SiO2复合胶体微球的有序组装;硬模板与催化材料一步复合的二元胶体体系颗粒的有序自组装;一种高效的聚苯乙烯胶体颗粒的批量组装技术;低体积分数聚苯乙烯胶体晶体的制备;以及聚苯乙烯胶粒晶体作为可调谐三维非线性光子晶体在高开关对比的光子晶体光开关方面的应用,和作为制备有序大孔材料硬模板在大分子催化方面的应用等.     

纳米银胶体颗粒制备新方法及其荧光增强效应研究

在纳米银胶体颗粒的制备中引入固相分散基体——天然纤维素,利用其表面丰富的羟基、醚基等含氧基团,均匀吸附银离子后,浸入低浓度硼氢化钠,经历脱附、还原过程生成银纳米颗粒的胶体溶液.与经典制备方法相比,反应过程温和且无需添加任何稳定剂,所制得的银纳米颗粒细小、均一、稳定性高.荧光增强实验表明,由于消除了大分子稳定剂的阻碍,胶体溶液在较低浓度下即可获得很好的荧光增强作用.     

化学法制备纳米银及其应用

采用液相化学还原法,以硝酸银作银源研究反应物的浓度、表面活性剂用量、温度等因素对纳米银形貌和粒径的影响。在常温,较高Ag NO3质量浓度(30 g/L)下,使用1.2 g的PVP制备出平均粒径在80 nm的纳米银胶,并探讨了其热性能与导电性能。结果表明,随着银胶质量浓度的增大,其导电性有所增加。所制备的纳米银胶不残留各种无机物,经浓缩后可直接获得导电油墨,避免了传统制备导电油墨过程的离心分散造成的产量损失与二次改性问题。     

纳米银材料绿色制备及其在水处理中的应用进展

针对纳米银粒子最常用的制备方法化学还原法中化学试剂的大量使用及其对环境的污染,结合近几年国内外的研究成果,介绍了纳米银的绿色制备方法,包括二糖法、多糖法、微生物合成法、植物提取物法等。同时介绍了纳米银离子在净水处理和废水处理方面的应用进展。分析认为,糖类作为还原剂可生成具有良好催化及杀菌性能的纳米银粒子。纳米银的形貌可控制备以及生物合成法中微生物及植物的选择技术等是今后纳米银绿色制备的发展方向。     

纳米银材料绿色制备及其在水处理中的应用进展

针对纳米银粒子最常用的制备方法化学还原法中化学试剂的大量使用及其对环境的污染,结合近几年国内外的研究成果,介绍了纳米银的绿色制备方法,包括二糖法、多糖法、微生物合成法、植物提取物法等。同时介绍了纳米银离子在净水处理和废水处理方面的应用进展。分析认为,糖类作为还原剂可生成具有良好催化及杀菌性能的纳米银粒子。纳米银的形貌可控制备以及生物合成法中微生物及植物的选择技术等是今后纳米银绿色制备的发展方向。     

纳米银的制备及其应用研究进展

介绍了不同形貌、大小纳米银的制备方法及纳米银在化工催化、光学、电子工业、生物医药等方面的应用,展望了纳米银的研究方向和应用前景。     

以SiO2为载体的纳米银粒子的制备及其在塑料中的应用

以硝酸银、无水乙醇、正硅酸乙酯(TEOS)、氨水、硼氢化钠为原料,通过溶胶凝胶法制备了载有纳米银的二氧化硅粒子,并将其与尼龙6共混,得到了抗静电的尼龙/(Ag/Si02)复合材料。以扫描电子显微镜(SEM)、X射线衍射(XRD)等手段对载银二氧化硅粒子进行了表征。测定了所制备的载银二氧化硅粒子和尼龙形成的复合材料的力学性能和电学性能,结果表明复合材料有较好的抗静电性能。     

石墨烯-纳米银修饰电极检测过氧化氢

以氧化石墨烯(GO)和硝酸银为原料,通过共合成法,制备了还原氧化石墨烯负载纳米银颗粒(AgNPs-rGO)复合物,并将AgNPs-rGO复合物修饰在碳糊电极(CPE)上,制得AgNPs-rGO/CPE电极。通过XRD、SEM和EDS技术对AgNPs-rGO的结构进行了表征与测试。结果表明,AgNPs很好地负载在了rGO上,且银元素的质量分数高达50.57%。当硝酸银浓度为0.02 mol/L时,AgNPs-rGO/CPE电极表现出最佳的电化学性能。在pH=5.5的磷酸盐缓冲溶液中,对过氧化氢在AgNPs-rGO/CPE电极上的电化学行为进行了考察。结果表明,AgNPs-rGO/CPE对过氧化氢的电化学检测表现出良好的稳定性,相对标准偏差仅为3.7%。当过氧化氢的浓度在1.0×10~(-8)~1.0×10~(-6)mol/L范围内时,过氧化氢的响应电流值ΔI与其浓度对数lgc呈现良好的线性关系,线性相关系数R~2高达0.993 4。将其应用于自来水样品中的过氧化氢检测,得到的加标回收率达到97.1%,多次重复检测的相对标准偏差仅为4.7%,表明制备的AgNPs-rGO/CPE对过氧化氢的电化学检测具有良好的重现性和稳定性。     

CdS纳米粒子的室温固相反应制备及其光催化活性研究

以牛血清白蛋白为稳定剂,采用CdSO4.8H2O、硫脲和NaOH之间的室温固相反应制备了高分散立方晶相粒径为4~5 nm的CdS纳米颗粒。用X射线洐射(XRD)、透射电镜(TEM)和原子力显微镜(AFM)对CdS纳米颗粒的相组成,形貌和粒径等进行了表征。以甲基橙降解脱色为探针反应,研究了自然光照条件下,CdS纳米颗粒的光催化活性,即光催化剂用量,试液的pH值,光照及时间等与甲基橙脱色率的关系。在最佳光催化剂用量为0.2 g,最佳pH值为1时,太阳光照射1 min,甲基橙降解率可达99%以上,表明由室温固相反应制备的CdS纳米颗粒,具有优异的光催化活性。     

氢氧直接合成法制过氧化氢技术进展

氢气和氧气直接合成过氧化氢是典型的原子经济性反应，因过程简单、产品清洁、生产成本低而成为催化领域研究开发的一个热点。总结了该法近年来在催化剂活性组分的选取及载体方面的进展；详细介绍了溶剂的选取和反应机理；讨论了各种反应器的安全性。指出今后的研究重点是提高氢气利用率、开发新型的反应器、提高过程的安全性。     

普鲁士蓝类纳米粒子的合成及其在双氧水检测中的应用

普鲁士蓝及其衍生物在具有优良的电化学性能、高稳定性等特点,在电化学领域发挥着重要的作用。文章用微乳法制备了Co-Fe普鲁士蓝类纳米粒子,并对其进行红外、电镜表征,发现其粒径均匀、呈立方状。同时,以此纳米粒子制备的修饰电极,对双氧水进行了检测,结果表明其电流的变化量与双氧水浓度的对数在0.48～5.74μmol·L-1范围内有线性响应。     

氢氧直接合成过氧化氢催化剂研究进展

从性组分和载体两方面,总结了近年来氢氧直接合成过氧化氢催化剂的研究进展,重点介绍了Au-Pd、Pt-Pd双金属催化剂在氢氧直接合成过氧化氢中的应用研究。指出负载型纳米双金属催化剂将是氢氧直接合成过氧化氢催化剂研究的发展方向。摘要：从活性组分和载体两方面，总结了近年来氢氧直接合成过氧化氢催化剂的研究进展，重点介绍了Au—Pd、Pt—Pd双金属催化剂在氢氧直接合成过氧化氢中的应用研究。指出负载型纳米双金属催化剂将是氢氧直接合成过氧化氢催化剂研究的发展方向。     

Superior Peroxidase-Like Activity of Gold Nanorattles in Ultrasensitive H2O2 Sensing and Antioxidant Screening

Nanozymes are artificial enzyme systems which are easy to produce, highly stable and cost-effective in comparison to natural enzymes. Herein, we evaluated the peroxidase-like activity of gold nanorattles (Au NRTs) having a solid gold octahedron core and thin, porous cubic gold shell. We also prepared solid gold nanocubes and nanospheres of similar sizes and surface charge as that of Au NRTs and compared their activity with standard horse radish peroxidase (HRP). All the prepared nanostructures followed Michaelis-Menten kinetics as observed from their substrate concentration vs. initial reaction velocity plot using 3,3’,5,5’-tetramethylbenzidine (TMB) as a substrate. The kinetic parameters and the catalytic efficiency for the peroxidase-like activity of the nanostructures and HRP were calculated, and it was observed that Au NRTs possess the best nanozymatic activity with lowest K_M and highest catalytic efficiency (k_cat/K_M). The better activity of Au NRTs compared with other nanostructures and HRP could be attributed to the hollow porous structure with a solid core where different surfaces are available for reaction. Au NRTs, being the best amongst the tested nanozymes were further used for the sensing of hydrogen peroxide (H₂O₂) and were found to sense H₂O₂ down to 0.5 μM. Further, two naturally occurring antioxidants, tannic acid and ascorbic acid showed inhibitory effect on the peroxidase-like activity of Au NRTs in a concentration dependent manner which can be further used for screening of antioxidants or for determining the antioxidant potential.     

Synthesis of Silver Nanoparticles and Detection of Glucose via Chemical Reduction with Nanocellulose as Carrier and Stabilizer

The application of silver nanoparticles (AgNPs) in antibacterial materials, glucose detection, etc., is of broad interest for researchers around the world. Nanocellulose with many excellent properties can be used as a carrier and stabilizer to assist in the synthesis of AgNPs. In this study, cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs) were used to assist in the synthesis of AgNPs under the reduction of glucose and detection of glucose concentration under different conditions. Transmission electron microscopy (TEM) analysis showed that the AgNPs in the nanocellulose-AgNPs (NC-AgNPs) system were roughly spherical and randomly distributed on the nanocellulose. In the whole reaction system, when the concentration of nanocellulose is 0.11 mg/mL, the concentration of silver ammonia solution is 0.6 mM, and the mixing time is 2.5 h, according to the UV-Vis analysis, the absorbance of CNF-AgNPs at 425 nm exhibited a good linear relationship (R² = 0.9945) with the glucose concentration range (5–50 μM), while the absorbance of CNC-AgNPs at 420 nm showed a good linear relationship (R² = 0.9956) with the glucose concentration range (5–35 μM). The synthesis of NC-AgNPs can be further developed into a sensor with higher sensitivity and higher stability for detecting glucose concentration and a material with antibacterial effects.     

Improvement of a-Si:H Thin-film Solar Cells by Employing Large Ag Nanoparticles

Silver (Ag) nanoparticles were formed on fluorine-doped tin oxide (FTO) coated glass substrate, and then hydrogenated amorphous silicon (a-Si:H) thin-film solar cells were sequentially fabricated. Ag nanoparticles located in the interface between the FTO and the p-layer leads to a light-trapping effect because of the strong light-material interaction in Ag nanoparticles and enhancement of the optical path length. A higher haze ratio appeared for Ag nanoparticles with larger diameters and heights, compared with the conventional type. The device with the Ag nanoparticles showed a short-circuit current density of 12.66 mA cm⁻², which was 2.2 mA cm⁻² higher than the device without Ag nanoparticles. Conversion efficiency increased from 4.9 % to 5.9 % by employing Ag nanoparticles with a roughness of 71 nm. The simple process makes our design useful for low-cost, high conversion efficiency thin-film solar cells.     

Co3O4 Nanoparticles Uniformly Dispersed in Rational Porous Carbon Nano-Boxes for Significantly Enhanced Electrocatalytic Detection of H2O2 Released from Living Cells

A facile and ingenious method to chemical etching-coordinating a metal-organic framework (MOF) followed by an annealing treatment was proposed to prepare Co₃O₄ nanoparticles uniformly dispersed in rational porous carbon nano-boxes (Co₃O₄@CNBs), which was further used to detect H₂O₂ released from living cells. The Co₃O₄@CNBs H₂O₂ sensor delivers much higher sensitivity than non-etching/coordinating Co₃O₄, offering a limit of detection of 2.32 nM. The wide working range covers 10 nM-359 μM H₂O₂, while possessing good selectivity and excellent reproducibility. Moreover, this biosensor was used to successfully real-time detect H₂O₂ released from living cells, including both healthy and tumor cells. The excellent performance holds great promise for Co₃O₄@CNBs’s applications in electrochemical biomimetic sensing, particularly real-time monitor H₂O₂ released from living cells.