银纳米粒子制备方法的研究进展

纳米粒子因具有比表面积大、小尺寸和宏观等优点,表现出许多一般材料不具有的特性,所以近年来对纳米材料的研究已成为人们关注的热点。纳米材料的物理、化学性质与其尺寸、大小、结构存在密切的关系,而液相还原法能够有效控制合成具有特定大小、形状、结构的纳米金属材料,是制备金属纳米材料最为普遍的一种方法。

蛋清生物模拟矿化合成荧光银纳簇和氰化物荧光探针

发展了一种合成荧光银纳簇的新方法。采用易得的生物蛋白材料蛋清,无需其他还原剂,调节pH值后,通过最简便的一锅孵化法制备了荧光银纳簇。这种合成方法类似于自然界的生物矿化现象:生物分子捕获无机离子,在功能性分子作用下进行矿化过程。高分辨透射电镜分析表明纳簇的粒径小于2 nm。该合成方法环保经济。紫外-可见吸收光谱和荧光发射光谱分析表明这种银纳簇能快速响应氰离子,导致吸光度减弱,并伴随荧光猝灭。基于此原理建立了一种检测氰离子的荧光传感新方法,此分析方法显示良好的线性范围和选择性,较高的灵敏度。检测限为1.2μmol.L-1,低于世界卫生组织推荐的饮用水标准(氰化物浓度不高于2.7μmol.L-1)。

Ni~Ⅱ-NTA修饰的银纳米粒/多孔硅芯片在线分离组氨酸标记蛋白和MALDI-TOF质谱检测(英文)

本文通过沉积在多孔硅表面的银纳米粒吸附对氨基苯硫酚和氨基的化学转化得到终端为NiII-Nα,Nα-二(羧甲基)-L-赖氨酸水合物-即NiⅡ-NTA体系的芯片。NiⅡ-NTA修饰的芯片被用于从高浓度的盐和助溶剂的缓冲体系中亲和捕获组氨酸标记的融合蛋白:thioredoxin-urodilatin和SUMO-hu-aprotinin,并进行在线的MALDI-TOF质谱检测,克服了MALDI-TOF质谱中直接点样污染物妨碍样品与基质共结晶的问题,避免了繁琐的离线样品预处理。芯片在线分离、纯化和MALDI-TOF质谱分析体系有望在复杂或原始体液的溶液中分析目标分子。

DNA稳定的银纳簇传感器对葡萄糖的定量检测

构建了一种新型的基于DNA银纳簇检测葡萄糖的生物传感器,酶催化底物产生的过氧化氢能够有效的猝灭DNA银纳簇,通过响应信号的变化能够用于葡萄糖的测定,检测线性范围为5.0×10-6～3×10-4M,检测限为2.4×10-6M。该方法简单、方便、灵敏度高。

Synthesis,characterization and antibacterial property of Ag/mesoporous CeO_2 nanocomposite material

Mesoporous CeO2 with high specific surface area was synthesized using a modified evaporation-induced self-assembly （EISA） method, and a series of different amounts of Ag were loaded to this mesoporous CeO2 by a modified ethylene glycol reduction route. The samples were characterized by powder X-ray diffraction （XRD）, transmission electron microscopy （TEM）, energy-dispersive spectrometry （EDS）, nitrogen adsorption-desorption, Brunauer-Emmett-Teller （BET） and Barrett-Joyner- Halenda （BJH） methods. The mesoporous CeO2 structure with different proportions of silver nanoparticles and its antibacterial activity were adequately studied, confinnin~ that obtained novel materials show a good antibacterial effect.

Hydrothermal synthesis of silver nanoparticles in Arabic gum aqueous solutions

Finely divided silver nanoparticles were synthesized via the hydrothermal method. Arabic gum （AG） was used as both the reductant and steric stabilizer without any other surfactant. By adjusting the reaction temperature, mass ratio of AG to AgNO3, and reaction time, silver nanoparticles with different morphological characteristics could be obtained. The products were characterized by UV-Vis, FTIR, TEM, SEM, and XRD measurements. It was found that temperature and AG played an important role in the synthesis of mono-disperse silver nanoparticles. Well dispersed and quasispherical silver nanoparticles were obtained under the optimal synthesis conditions of 10 mmol/L AgNO3, m（AG）/m（AgN03）= l：1, 160 ℃ and 3 h.

Preparation and Fluorescence Properties of Co-doped Nanocomposite Film Based on Supra Molecular Structure

A novel materials design procedure based on the co-doping of metal nanoparticle and azo dye compound （MNPADC） is developed to improve the properties of functional molecules. The synthesized materials were characterized by transmission electron micrograph （TEM）, ultraviolet-visible absorption spectra （UV-Vis） and fluorescence spectra （FS）. It was found that the fluorescence intensity of methyl orange （MO） was enhanced by 5 times in the aqueous composite system doped with silver nanoparticles whereas it was reduced by 15% and 20% in composite films with co-mixing and coating structures, respectively. The results indicate that the properties of functional molecules can be greatly improved in composite film with supra molecular structure and that the procedure presented here is effective.

Improvement of hybridization signals of gold label silver stain gene detection

The factors that influence the colorimetric gene detection of gold label silver stain and improve the detection signals were studied. The influence of amino DNA probes and thiol DNA modified gold nanoparticles was investigated based on a sandwich hybridization system. An increase in amino probe concentration brought about an increase in hybridization signal which reached a threshold corresponding to the saturated concentration of amino probes bounded onto a glass slide surface. Since the steric hindrance effect of nanoparticles was dominant over the influence of a surface area, the bigger gold nanoparticles led to weaker hybridization signals. The hybridization efficiency enhanced significantly with the increase of the thiol DNA modified nanoparticle concentrations. Experimental results showed that 125 μmol/L of the amino DNA probe concentration, 15 nm of the gold nanoparticle diameter, and 4.07 nmol/L of the thiol DNA modified gold nanoparticle concentration were optimal for the detection system. The hybridization signals can be improved remarkably by choosing optimal hybridization conditions.

Synthesis of Cu2O/Ag Composite with Visible Light Photocatalytic Degradation Activity for in situ SERS Analysis

A multifunctional Cu2O/Ag micro-nanocomposite, which has the characteristics of high cat- alytic activities under the visible light and high surface-enhanced Raman scattering （SERS） activity, was fabricated via a facile method and employed for the in situ SERS monitoring of the photocatalytic degradation reaction of crystal violet. Through the variation of the AgNO3 concentration, Ag content on the Cu2O template can be controllably tuned, which has great influence on the SERS effect. The results indicate that Ag nanopartieles form on the Cu2O nanoframes to obtain the Cu2O/Ag nanoeomposite, which can act as an excellent bifunetional platform for in situ monitoring of photocatalytic degradation of organic pollutions by SERS.

Enhancement effect of terbium complex luminescence by binding to silver nanoparticles in the solution

The luminescent properties of terbium complex (terbium citrate) by binding to silver nanopartilces in the solution have been reported in this paper.The enhanced luminescence of the complex containing silver nanoparticles was observed at a limited particle concentration region.The nanoparticle concentration dependence of the luminescent intensity was regarded as the result of a delicate balance between an enhancing and a quenching effect of the silver nanoparticles.Furthermore,silver nanoparticles also affected the asymmetric ratio (AS) value of terbium luminescence.We discuss the luminescent properties of the terbium complex in terms of the local electromagnetic field,refractive index,and the ligand field around terbium ion.

Electrochemical Behavior and Specific Capacitance of Polyaniline/Silver Nanoparticle/Multi-walled Carbon Nanotube Composites

In this work, we fabricated the polyaniline/silver nanoparticle/multi-walled carbon nanotube （PANI/Ag/MWCNT） composites by in situ polymerization of aniline on the wall of Ag/MWCNTs with different aniline to Ag/MWCNT mass ratios. The chemical structure of the ternary composites was characterized by Fourier transform infrared spectroscopy, Xray diffraction, and X-ray photoelectron spectroscopy. Scanning electron microscope and high-resolution transmission electron microscopy were used to observe the morphology of the ternary composites. The results showed that the polyaniline PANI layer was prepared successfully and it covered Ag/MWCNTs completely. In addition, Ag nanoparticles between the MWCNT core and the PANI layer existed in the form of elemental crystal, which could contribute to the electrochemical performance of the composites. Then we prepared the composite electrodes and studied their electrochemical behaviors in 1 mol/L KOH. It was found that these composite electrodes had very low impedance, and exhibited lower resistance, higher electrochemical activity, and better cyclic stability compared with pure PANI electrode. Particularly, when the mass ratio of aniline to Ag/MWCNTs was 5：5, the composite electrode displayed a small equivalent series resistance （0.23 Ω） and low interfacial charge transfer resistance （〈0.25 Ω）, as well as 160 F/g of the maximum specific capacitance at a current density of 0.25 A/g in KOH solution. We could conclude that the composite material had potential applications as cathode materials for lithium batteries and supercapacitors.

Ultrasonic-Assisted Synthesis of Monodisperse Ag Nanoparticles and Their Applications in Surface Enhanced Raman Scattering and Fluorescence Enhancement

Monodisperse Ag nanoparticles with diameters of about 3.4 nm were synthesized by a facile ultrasonic synthetic route at room temperature with the reduction of borane-tert-butylamine in the presence of oleylamine （OAm） and oleic acid （OA）. The reaction parameters of time, the molar ratios of OAm to OA were studied, and it was found that these parameters played important roles in the morphology and size of the products. Meanwhile, surface enhanced Raman spectrum （SERS） property suggested the Ag nanoparticles exhibited high SERS effect on the model molecule Rhodamine 6G. And also, two-photon fluorescence images showed that the silver nanoparticles had high performances in fluorescence enhancement.

Antimicrobial Expanded Polytetrafluoroethylene Film Prepared by 3-ray Radiation Induced Grafting of Poly（acrylic acid）

The simultaneous γ-ray-radiation-induced grafting polymerization of acrylic acid on ex- panded polytetrafluoroethylene （ePTFE） film was investigated. It was found that the degree of grafting （DG） of poly（acrylic acid） （PAA） can be controlled by the monomer concentration, absorbed dose, and dose rate under an optimal inhibitor concentration of [Fe2＋]=18 mmol/L. SEM observation showed that the macroporous structure in ePTFE films would be covered gradually with the increase of the DG of PAA. The prepared ePTFE-g-PAA film was im- mersed in a neutral silver nitrate solution to fabricate an ePTFE-g-PAA/Ag hybrid film after the addition of NaBH4 as a reduction agent of Ag＋ to Ag atom. SEM, XRD, and XPS results proved that Ag nanoparticles with a size of several tens of nanometers to 100 nanometers were in situ immobilized on ePTFE film. The loading capacity of Ag nanoparticles could be tuned by the DG of PAA, and determined by thermal gravimetric analysis. The quart- titative antibacterial activity of the obtained ePTFE-g-PAA/Ag hybrid films was measured using counting plate method. It can kill all the Escherichia coli in the suspension in 1 h. Moreover, this excellent antibacterial activity can last at least for 4 h. This work provides a facile and practical way to make ePTFE meet the demanding antimicrobial requirement in more and more practical application areas.

Controllable Electrochemical Synthesis of Silver Dendritic Nanostructures and Their SERS Properties

Ag dendritic nanostructures were synthesized on fluorine-doped tin oxide covered glass sub- strates by the electrodeposition method. Results demonstrate that the size, diameter, crys- tallinity, and branch density of the Ag dendrites can be controlled by the applied potential, the surfactants and the concentration of AgNO3. Three kinds of typical silver dendrites were applied as substrates of the surface enhanced Raman scattering （SERS） and one of them was able to clearly detect rhodamine 6G concentrations up to 0.1 nmol/L. The differences of the SERS spectra at these Ag dendrites confirmed that the shapes and interparticle spacings have great effect on Raman enhancement, especially the interparticle spacings.

Capping effect of reducing agents and surfactants in synthesizing silver nanoplates

The effect of reducing agents and surfactants on controlling the silver nanoplates was studied. Two reducing agents, trisodium citrate dehydrate (TSC) and potassium tartrate, were used to reduce the AgNO3 solution. In this redox system, polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS) and arabic gum were served as surfactants. The results showed that reducing agents and surfactants both act as the capping agent adhering to the certain facets of silver seeds to block this surface to grow. The relative intensity of reducing agents also takes an active part in influencing the growth rate and direction of silver seeds. It was also found that halides can accelerate the speed of Ostwald ripening by adding Cl?, Br? and I?into the aqueous and have some effects on the morphology of the nanoplates.

Cathode made of compacted silver nanoparticles for electrocatalytic carboxylation of 1-phenethyl bromide with CO_2

Silver nanoparticles prepared by the direct reduction of AgNO3 in aqueous solution were compacted into coins and used as the cathode for the electrocatalytic carboxylation of 1-phenethyl bromide with CO2. The influences of the working electrode, charge, current density and temperature were investigated. Under optimized conditions, 98% yield of 2-phenylpropionic acid was obtained. The reaction was performed under very mild conditions and no added catalyst was required in the electrolyte. Yields that varied from moderate to excellent were also achieved with other benzyl bromides. This electrode has good stability and reusability, and the yield and selectivity of 2-phenylpropionic acid could be maintained during reuse for 10 times.

Light-induced ZnO/Ag/rGO bactericidal photocatalyst with synergistic effect of sustained release of silver ions and enhanced reactive oxygen species

Silver nanoparticles (Ag NPs) can effectively address the issue of antibiotic-resistant bacterial infections to reduce the potential toxicity of Ag NPs. Although challenging, it is, therefore, necessary to achieve the sustainable release of Ag+ ions from a finite amount of Ag NPs. This study aims at designing an efficient and benign antimicrobial silver-based ternary composite composed of photocatalysis zinc oxide (ZnO) and reduced graphene oxide (rGO) as a carrier, in which the reactive oxygen species (ROS) excited from ZnO and Ag+ ions released from the Ag NPs cooperate to realize an effective antibacterial activity against E. coli and S. aureus. The constant effective bacterial performance of the ternary photocatalyst with minimum Ag content can be attributed to the increase in the available quantity of ROS, which results from the enhanced separation efficiency of the photogenerated carriers. The proposed system notably realized the long-term sustainable release of Ag+ ions with low concentration for 30 days when compared with an equivalent amount of silver nitrate. Moreover, the use of the composite prevents biotoxicity and silver wastage, and imparts enhanced stability to the long-lasting antibacterial efficacy.

Transparent Electronic Skin Device Based on Microstructured Silver Nanowire Electrode

Transparent, flexible electronic skin holds a wide range of applications in robotics, humanmachine interfaces, artificial intelligence, prosthetics, and health monitoring. Silver nanowire are mechanically flexible and robust, which exhibit great potential in transparent and electricconducting thin film. Herein, we report on a silver-nanowire spray-coating and electrodemicrostructure replicating strategy to construct a transparent, flexible, and sensitive electronic skin device. The electronic skin device shows highly sensitive piezo-capacitance response to pressure. It is found that micropatterning the surface of dielectric layer polyurethane elastomer by replicating from microstructures of natural-existing surfaces such as lotus leaf, silk, and frosted glass can greatly enhance the piezo-capacitance performance of the device. The microstructured pressure sensors based on silver nanowire exhibit good transparency, excellent flexibility, wide pressure detection range （0-150 kPa）, and high sensitivity （1.28 kPa-1）.

Ag nanoparticles deposited on oxygen-vacancy-containing BiVO_4 for enhanced near-infrared photocatalytic activity

This study investigates the photodegradation of the organic dye rhodamine B by Ag‐nanoparticlecontaining BiVO4catalysts under different irradiation conditions.The catalysts consist of Ag nanoparticles deposited on oxygen‐vacancy‐containing BiVO4.The morphology of the BiVO4is olive shaped,and it has a uniform size distribution.The BiVO4possesses a high oxygen vacancy density,and the resulting Ag nanoparticle‐BiVO4catalyst exhibits higher photocatalytic activity than BiVO4.The RhB degradation by the Ag nanoparticle‐BiVO4catalyst is99%after100min of simulated solar irradiation.BiVO4containing oxygen vacancies as a rationally designed support extends the catalyst response into the near‐infrared region,and facilitates the trapping and transfer of plasmonic hot electrons.The enhanced photocatalytic efficiency is attributed to charge transfer from the BiVO4to Ag nanoparticles,and surface plasmon resonance of the Ag nanoparticles.These insights into electron‐hole separation and charge transfer may arouse interest in solar‐driven wastewater treatment and water splitting.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.

Fabrication and catalytic behavior of hierarchically-structured nylon 6 nanofiber membrane decorated with silver nanoparticles

A hierarchically‐structured nylon 6 (PA6) nanofiber membrane decorated with silver nanoparticles (Ag NPs) was fabricated by electrospinning and impregnation methods. The as‐fabricated hierarchically‐structured Ag/PA6 nanofiber membrane (HS‐Ag/PA6 NM) exhibits a morphology in which Ag NPs are deposited on the surfaces of both thick fibers and thin fibers. The content and size of theAg NPs can be controlled by varying the concentration of the silver colloid solution. Compared with the non‐hierarchically‐structured Ag/PA6 nanofiber membrane, HS‐Ag/PA6 NM has a higher specificsurface area and exhibits a higher degradation rate for methylene blue of 81.8%–98.1% within2 h. HS‐Ag/PA6 NM can be easily recycled and exhibits good reusability. It retains a degradation rate for methylene blue of 83.5% after five consecutive cycles. The hierarchically‐structured nanofiber membrane is therefore a potential nanocatalyst.