DNA Immobilization on Nano-Gold Modified Glassy Carbon Electrode

CT-DNA were electrochemically immobilized on the surfaces of both nano-gold modified glassy carbon electrode and bare glassy carbon electrode. The cyclic voltammetric behavior of Co (phen)(3)(3+) adsorbed on the immobilized DNA was studied. Increase in the peak current of Co (phen)(3)(3+) redox reaction was obtained on nano-gold modified glassy carbon electrode. The result suggests that more DNA molecules were immobilized on this electrode and nano-gold modification can enhance the heterogeneous electron transfer rate constant of the Co (phen)(3)(3+).

Cyclic Voltammetry Determination of Epinephrine with a Nano-gold Modified Glassy Carbon Electrode in the Presence of High Concentration Ascorbic Acid

Nano-gold (NG) modified glassy carbon electrodes (GCEs) were used for determination of epinephrine (EP) in the presence of high concentration ascorbic acid (AA) by cyclic voltammetry (CV). This modified electrode can not only catalytically oxidize EP and AA, but also separate the catalytic peak potentials of EP and AA by about 183.5 mV. In pH = 7.0 ogisogate byffer solution, the linear range of epinephrine was 5 106 ~ 1 ?10-4 mol/L.

The Study of Electrochemical Behavior of Dopamine at Nano-gold Modified Carbon Fiber Electrode

The electrochemical behaviors (cyclic voltammetry, CV and different pulse voltammetry, DPV) of dopamine (DA) were studied in this paper. The result indicated that the oxidation of dopamine was controlled by diffusion and adsorption simultaneously at nano-gold (NG) modified carbon fiber electrode (CFE). This modified electrode can separate the peak potentials of dopamine and ascorbic acid (AA). The peak current of DA in DPV curve was found to be linearly proportional to the concentration of DA at range of 2.0?0-6～1.5?0-5mol/L and 1.0?0-5～5.0?0-4mol/L, respectively.

Influence of MgO contents on silica supported nano-size gold catalyst for carbon monoxide total oxidation

A series of nano-size gold catalysts were prepared by deposition-precipitation method using silica material promoted with different amounts of MgO as the carrier. The influences of MgO addition on the structure and property of the nano-size gold catalysts were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, O2 temperature-programmed desorption （O2-TPD）, and inductively coupled with plasma atomic emission spectroscopy （ICP-AES） techniques. The total oxidation of CO was chosen as the probe reaction. The results suggest that for the gold catalysts supported on the silica material after MgO modification, the size of the gold particles is pronouncedly reduced, the oxygen mobility is enhanced, and the catalytic activity for low-temperature CO oxidation is greatly improved. The gold catalyst modified by 6 wt% MgO （Mg/SiO2 weight ratio） shows higher CO oxidation activity, over which the temperature of CO total oxidation is lower about 150 K than that over the silica directly supported gold catalyst.

Determination of ppt Level Chromium(VI) Using the Gold Nano-Flakes Electrodeposited on Platinum Rotating Disk Electrode and Modified with 4-Thiopyridinium

The nano-gold layer formed on the platinum rotating disk electrode (nano-Au/Pt-RD) inherited the catalytic property for Cr(VI) reduction from platinum surface and owned the good features of nano-gold such as insensitivity with hydrogen ion, high surface area, augmenting diffusion of Cr(VI) and ability for self-assembling with 4-pyridine-ethanethiol (PET) through Au←S linkages, to form PET/nano-Au/Pt-RD electrode capable of accumulating Cr(VI) from sample. The obtained PET/ nano-Au/Pt-RD electrode showed an extreme sensitivity to Cr(VI). By using this electrode, 1.09 ng·L﹣1 was the detection limit of differential pulse adsorptive cathodic stripping voltammetry for Cr(VI) with the accumulation time of only 2 min. Moreover, this electrode was reproducible with 3.5% RSD for 30 times of Cr(VI) accumulating and stripping. In addition, this electrode was also selective for Cr(VI) determination, which was not almost interfered by other inorganic ions.

State-space approach to vibration of gold nano-beam induced by ramp type heating

In the nanoscale beam,two effects become domineering.One is the non-Fourier effect in heat conduction and the other is the coupling effect between temperature and strain rate.In the present study,a generalized solution for the generalized thermoelastic vibration of gold nano-beam resonator induced by ramp type heating is developed.The solution takes into account the above two effects.State-space and Laplace transform methods are used to determine the lateral vibration,the temperature,the displacement,the stress and the strain energy of the beam.The effects of the relaxation time and the ramping time parameters have been studied.

Assembling Tunable Time-Resolved Fluorescence Layer onto Nano-Gold

The assembling of a coating of time-resolved fluorescent chelator BSPDA （ abbreviated for 4, 7-bis （ sulfhydrylphenyl）-1, 10-phenanthroline-2, 9-dicarboxylic acid） onto a nano-gold layer was demonstrated. First, BSPDA was synthesized by simple procedures, and then an approach was developed to immobilize BSPDA onto the nano-gold layer deposited on a silane modified glass substrate, whereby europium ion （Ⅲ, Eu^3＋ ） was captured and released owing to the interactive process of complexation and dissociation between BSPDA functionalized coating and Eu^3＋ solution. The fluorescence spectra and related lifetimes were determined. Also, the BSPDA functionalized coating＇s specific complexation with Eu^3＋ on the BSPDA assembly layer and the nonspecific adsorption of Eu^3＋ on the nano-gold layer were compared. These results allowed a selective complexation of Eu^3＋ by assembling a BSPDA chelating layer on the nano-gold layer; thus, a tunable time-resolved fluorescent layer was covalently attached, The results of the nanoparticle assembling and probing （or labeling） processes to specific bio-systems were very interesting and had significant implications to time-resolved-fluorescence-based detection on biosensor surfaces such as DNA chip and to arrayed light display devices.

Potential Applications of Nano-Scale Science and Technology in Geosciences and Experimental Studies of Nanometer-Sized Gold Adsorption on Minerals and Rocks

Potential applications of Nano-scale science and technology are discussed in mineralogy, ore deposits, cosmochemistry and environmental sciences. Adsorption of nanometersized gold was experimentally studied on a variety of minerals and rocks.

Electrochemical Determination of Melamine on Static Mercury Drop Electrode and on Gold Nano Particle Modified Carbon Paste Electrode

An electrochemical method was developed for the determination of melamine (2,4,6 triamino- 1,3,5-triazine) on static mercury drop electrode (SMDE) and on gold nano particle modified carbon paste electrode. Interaction of melamine with Cu2﹢ ion was investigated and the decrease of Cu stripping peak was measured for the determination of melamine using SMDE. Oxidation property of melamine was improved using gold nano particle modified carbon paste electrode. Direct determination of melamine was proposed from the oxidation peak with three sigma detection limit of 0.43 μML﹣1. Recovery in milk powder sample has shown good recovery of melamine using the modified carbon paste electrode.

Heating of Biological Tissues by Gold Nano Particles: Effects of Particle Size and Distribution

This paper deals with hyper thermal therapy of tumors in biological tissues using dispersions of gold nano spheres. These spheres are heated with a laser beam in the near infrared range based on surface plasmon resonance phenome-non. The single sphere problem gives a surface temperature rise following a universal form with a characteristic time τ proportional to the sphere surface and inverse diffusivity of the surrounding medium. The temperature front is found to reach a finite range when traveling into the surrounding medium with a certain time delay. The many particles problem is treated as a convolution product of the sphere density distribution function and the particle temperature profile. Different space distribution functions of nano particles are considered. A uniform sphere distribution provides a good coverage of medium heating while a Gaussian distribution predicts an important drop of temperature when approaching the borders of the treated region. Lorentzian distribution was also considered for comparison. An effort is made to highlight the impacts of the obtained results in developing strategies for hyper thermal therapy in a joint effort with the medical team.

Nano-Microplate Gold Clay for Handcraft Jewelry and Decoration

Gold clay is a crafting medium consisting of gold particles mixed with an organic binder and water for making jewelry or decoration.The clay can be shaped by hand,textured,carved,formed or using molds.After drying and burning,the organic binder and water were decomposed and the gold particles were transformed to its final metal state.Although,gold clay is very expensive,it is useful to decorate the silver clay designed jewelry or small sculptures.In this research,nano-microplate gold and specific organic binder was used for producing nano-microplate gold clay.The objectives of this research are to study binder's type and ratios for optimum producing gold clay,and to study the heating condition for making silver and gold clay jewelry.The result showed that the clay can be fired with heating temperature at 900°C for an hour by electric kiln.The physical properties of the gold clay at different heating temperatures were determined.Furthermore,prototype of jewelry using the clay was

On the Hyper Thermal Therapy of Tumor Tissues by Direct Laser Heating and Gold Nano Particles

Hyper thermal therapy using lasers is emerging as a new promising route for the cancer treatment. The tumor can be directly heated by the radiation or indirectly using gold nano particles based on plasmon resonance phenolmenon. These two possibilities are explored here by solving the space and time dependent bio-heat equation under different conditions. The knowledge of temperature profiles in the tumor region helps to bypass the painful placement of sensors for monitoring tumor’s heating by the laser. Important properties which could be useful for developing an efficient tumor therapy are introduced for the first time. It is found that the effects of metabolism consist essentially in a redefinition of the blood temperature which increases proportional to the heat of metabolism. Blood perfusion in a given tissue leads to a new characteristic length of order one or two centimeters and a blood convection parameter typically of order 30 W·m-1·K-1. Effects of these parameters are scrutinized within the resolution of the bio-heat equation under a variety of conditions. In general, space modulations of the temperature throughout biological tissues are weak but front kinetics are quite fast. Specific examples show the way to monitor the temperature rise taking into account the tumor’s nature and size.

甘肃阳山金矿载金黄铁矿硫同位素Nano-SIMS原位分析

硫同位素示踪是矿床研究的重要手段之一,它在示踪成矿物质来源方面具有极其重要的作用。由于阳山金矿床的载金黄铁矿普遍发育环带结构,显示多期热液活动的特点,而前人研究往往得到整颗粒黄铁矿硫同位素的混和值,因而无法将不同阶段的硫同位素来源区分清楚。本次研究采用纳米二次离子质谱分析技术(NanoSIMS)对不同阶段的黄铁矿的不同部位进行了原位硫同位素分析。结果表明,斜长花岗斑岩脉中载金黄铁矿的硫同位素分布基本表现为核部高、环带低的特点,其中,黄铁矿核部的δ34S值为0~1.3‰,显示硫来自于深源岩浆,而环带的δ34S值为-4.5‰^-1.3‰,表明成矿过程中的硫主要来源于岩浆硫,同时可能还有部分沉积硫的混入;千枚岩中草莓状黄铁矿和自形黄铁矿核部的δ34S值均较低(平均值分别为-22.2‰和-26.5‰),显示细菌还原海水硫酸盐过程所产生的硫同位素特征,而自形黄铁矿环带的δ34S值为-5.1‰~1.3‰,同样显示硫来源于岩浆硫与一定程度沉积硫的混合。笔者综合研究区内岩浆活动与成矿的关系后认为,岩浆活动与成矿关系密切,岩浆活动的频发不仅为流体运移提供了足够的热源,同时还带来了丰富的成矿物质。

纳米金颗粒@介孔二氧化硅修饰钛种植体促进高糖条件下的成骨分化

背景:微纳米结构改性是钛种植体表面处理的热点研究领域。糖尿病高血糖环境会影响钛种植体与骨组织形成稳定的结合,探索通过表面微纳结构改性来提高钛种植体在高糖环境下的成骨活性是有必要的。目的:观察钛表面纳米金颗粒@介孔二氧化硅涂层对体外高糖条件下成骨分化的影响。方法:分别制备纳米金颗粒悬浮液与介孔二氧化硅,将二者按一定比例混合在去离子水中,制备纳米金颗粒@介孔二氧化硅悬浮液。取钛片,分3组处理:光滑组经过水砂纸打磨处理,纳米管组经过水砂纸打磨处理后采用阳极氧化技术制备二氧化钛纳米管涂层,实验组制备二氧化钛纳米管涂层后浸泡于纳米金颗粒@介孔二氧化硅悬浮液中,制备纳米金颗粒@介孔二氧化硅涂层,表征3组钛片表面的微观形貌、亲水性。将大鼠骨髓间充质干细胞接种于3组钛片表面,通过细胞活/死荧光染色及CCK-8实验检测细胞增殖,DAPI/鬼笔环肽染色检测细胞黏附。将大鼠骨髓间充质干细胞接种于3组钛片表面,加入高糖成骨诱导培养基培养,通过碱性磷酸酶与茜素红S染色检测成骨分化。结果与结论:(1)扫描电镜下可见光滑组钛片表面均匀平坦,纳米管组钛片表面排列紧密的二氧化钛纳米管阵列,实验组钛片在二氧化钛纳米管表面及内部均负载纳米金颗粒@介孔二氧化硅;纳米管组、实验组钛片亲水性均优于光滑组。(2)细胞活/死荧光染色结果显示,3组钛片表面的细胞活力均高于90%;CCK-8实验结果显示,实验组细胞增殖率高于光滑组、纳米管组;DAPI/鬼笔环肽染色结果显示,二氧化钛纳米管涂层、纳米金颗粒@介孔二氧化硅涂层更有利于细胞黏附。(3)碱性磷酸酶与茜素红S染色结果显示,实验组钛片表面细胞碱性磷酸酶活性与细胞外基质矿化程度均高于光滑组、纳米管组。(4)结果表明,纳米金颗粒@介孔二氧化硅涂层可增强钛表面生物活性,促进高糖环境下的成骨分化。

基于rGO-AuNPS修饰丝网印刷电极的电化学生物传感器快速检测甲基对硫磷

目的:实现对甲基对硫磷的快速检测。方法:基于金纳米颗粒和还原氧化石墨烯制备了用于对甲基对硫磷进行定量检测的乙酰胆碱酯酶传感器。采用层层组装方法,将还原氧化石墨烯、金纳米颗粒、乙酰胆碱酯酶依次修饰在丝网印刷电极表面。对传感器的催化活性、阻抗特性、传感器的抑制率与甲基对硫磷浓度的关系、实际样品检测进行了评估。结果:制备的乙酰胆碱酯酶生物传感器对乙酰硫代胆碱氯化物表现出优异的亲和力,米氏常数为2.76 mmol/L。在最佳条件下,可以有效检测甲基对硫磷,线性范围为5~500 ng/mL,检出限为0.692 ng/mL。结论:该方法操作简单、成本低、稳定性好,适用于有机磷类农药的快速检测。

Optical Absorption of Nano-Composite Thin Films of Au in Teflon

Nano-composite films of Au particles in Teflon were obtained by thermal vacuum deposition. The obtained films were characterized by the different shapes and dimensions of the inclusion particles. Absorption spectra of the films were measured in-situ. A model for the calculation of the optical properties of the nano-composite thin films with an inho-mogeneous distribution of the inclusions along the thickness of the film is proposed. Absorption properties of inclusions were analyzed by considering the local field interaction. The calculated absorption profiles are compared with the experimentally obtained absorption profiles. This comparison gives a possibility to draw conclusions about the concentration, shapes and shape distributions of the inclusion particles. For example, the films obtained by duration deposition are characterized by inclusions having the shape of prolate ellipsoids oriented normally to surface of the film.

一种检测砷(Ⅲ)的适配体试纸条

利用三明治夹心法构建基于适配体胶体金的试纸条,目的在于开发切实可行的As(Ⅲ)检测应用装置。通过As(Ⅲ)与金标适配体的特异性结合,将其截留在试纸条检测线处。纳米金作为显色材料,其颗粒直径为(13±1)nm。经过优化反应条件,选择Satorius CN 140作为硝酸纤维素膜,控制线上捕获探针链霉亲和素与生物素的最佳比例为1∶4,对应的划线浓度为10μmol/L。检测线上1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐与N-羟基琥珀酰亚胺的最优比例为1∶3,金标适配体最优浓度为0.5μmol/L。在最佳反应条件下,观察试纸条的显色结果,颜色响应信号与砷浓度形成很好的梯度关系,检测限为0.1μmol/L。本试纸条对As(Ⅲ)具有高度的特异性,并且稳定性良好。其检测成本不足1元,可满足低收入地区普通人群实时检测As(Ⅲ)的要求。

碳量子点/纳米金复合物的合成及其对重金属离子的特异性检测

碳量子点/纳米金复合物用于检测印染废水中的铅离子。碳量子点/纳米金优化合成条件为:温度180℃,时间6 h。对合成的碳量子点/纳米金复合物进行红外光谱、紫外光谱、X射线光电子能谱结构表征。加入谷胱甘肽后,碳点会发生红色-蓝色-红色的颜色变化,可用于铅离子(Pb^(2+))的可视分析。铅离子的线性回归方程为:y=-42.07x+302.43,R^(2)=0.9941,检出限为0.19μg/L。将该碳量子点/纳米金复合物用于印染废水中Pb^(2+)的快速检测,加标回收率为95.5%~101.6%,方法简便、快捷。

基于金纳米粒子-纳米氧化铈-石墨烯复合物修饰电极对环境水体中As(Ⅲ)的检测

先通过滴涂法制备纳米氧化铈-石墨烯(CeO_(2)-Gr)复合物修饰玻碳电极(GCE),再在含氯金酸(HAuCl_(4))的缓冲溶液中,采用循环伏安法将Au(Ⅲ)还原到CeO_(2)-Gr表面,从而制得AuNPs/CeO_(2)/Gr/GCE。采用电化学阻抗谱法(EIS)对修饰电极进行电化学特性表征。研究了AuNPs/CeO_(2)/Gr/GCE快速、准确测定水环境中As(Ⅲ),采用差分脉冲溶出伏安法,探讨了氧化铈与石墨烯质量比、金纳米粒子沉积圈数、沉积时间和沉积电位及干扰离子等对测定结果的影响,并确定检测As(Ⅲ)的优化实验条件。在最优条件下,该电化学传感器对As(Ⅲ)具有良好的电流响应,其溶出伏安峰电流与As(Ⅲ)浓度的线性范围为13.35~387.15μmol/L,检出限为4.74μmol/L。在不同干扰离子存在的情况下,传感器对As(Ⅲ)的选择性较好。为了评估传感器的实际应用能力,以实验室自来水为样本进行As(Ⅲ)加标检测,加标回收率为90.5%~99.2%,表明该电化学传感器具有监测As(Ⅲ)的应用潜力。