金纳米棒对SPR生物传感器灵敏度的增强效应

研究不同长径比的金纳米棒对表面等离子体共振(SPR)生物传感器灵敏度的增强效应.利用晶种生长法合成不同长径比的金纳米棒,并对其形貌、光学性质进行表征.采用双抗体夹心法,以金纳米棒 与羊抗人IgG的偶联体作为第二抗体,利用实验室自行研制的波长调制SPR生物传感器对人IgG进行测 试.实验结果表明:不同长径比的金纳米棒...     

纳米金增强DNA修饰金电极电化学性能

纳米金自组装于金电极表面可以增强DNA在电极表面的固着量.用恒电位吸附的方式将小牛胸腺DNA修饰到金电极上,并通过Co(bpy)33+表征修饰电极的电化学性能.比较了在纳米金修饰金电极上吸附的DNA数量与在裸金电极上吸附DNA的数量,前者有明显的增大,并考察了DNA修饰金电极的稳定性.探讨了ssDNA与dsDNA的吸附特性,同时,比较了DNA在不同电极基体上的吸附行为特性.     

基于“树枝状”信号放大的电化学DNA生物传感器研究

发展了一种基于"树枝状"信号放大的电化学生物传感器用于DNA的检测。该传感器利用两种DNA功能化的纳米金颗粒,通过两次"三明治"杂交,在电极表面形成"树枝"状结构,从而实现DNA的定量检测。首先通过共价交联方法获得巯基DNA1和DNA2修饰的两种纳米金颗粒,其中DNA1和DNA2与目标cDNA部分互补。然后,修饰在金电极上的捕获探针DNA1与目标cDNA分子及巯基DNA2修饰的纳米金颗粒(DNA2-AuNPs)形成第一个"三明治"杂交结构,实现一次放大检测。接着,DNA2-AuNPs又可与cDNA、巯基DNA1修饰的纳米金颗粒(DNA1-AuNPs)形成第二个"三明治"杂交结构,实现二次放大检测。这种"树枝状"放大信号的方法的检测限是0.13pmol/L,相对仅利用纳米金颗粒放大的方法而言,其检测限降低了4倍。并且,该传感器具有较好的识别碱基错配的能力。     

无标记纳米金传感显色测定五氯苯酚

该文基于纳米金(AuNPs)颜色随盐致聚集而变化的特点,发展了测定五氯苯酚的无标记纳米金传感显色法。金纳米粒子在一定浓度盐的作用下发生团聚,而单链DNA(ssDNA)可以吸附在金纳米粒子表面保护金纳米粒子不团聚。羟基自由基能破坏ssDNA的结构,使其丧失对金纳米粒子的保护功能。该文利用PCP可以消耗羟基自由基,保护ssDNA,从而保护金纳米溶胶的稳定性,实现对PCP的测定。     

金纳米棒的合成、修饰及与肿瘤细胞的相互作用

作为金属纳米粒子中的典型代表,金纳米棒在近红外区有较强的吸收,且容易合成得到尺寸均匀的产物,这使它在医学上有着巨大的应用潜力.但是关于金纳米棒的生物毒性以及金纳米棒与肿瘤细胞相互作用的机理目前尚未得到很好的解决.实验进行了金纳米棒合成条件的优化,成功合成了所需波长范围的金纳米棒,利用巯基十一酸层层组装法制备了单分散的表...     

DNA在SiO2纳米粒子薄膜表面的单分子行为研究

基于应用全内反射荧光显微镜,利用YOYO-1标记的λ-DNA分子作为探针研究了SiO2纳米粒子薄膜的表面性质,在不同的pH值下,考察了pH值对单个DNA分子在其表面行为(自由运动和吸附)的影响,并采用接触角(CA)和原子力显微镜(Atomic Force Microscope,AFM)表征了SiO2纳米粒子薄膜表面的性质.实验表明,随着pH值的降低,DNA分子在其表面的吸附率随之增大.DNA分子在SiO2纳米粒子薄膜表面的吸附行为是静电作用和疏水作用共同作用的结果,但是起主导作用的是疏水作用.此外,相同pH值下,与文献中报道的DNA在玻片上的吸附率相比,DNA在SiO2纳米粒子薄膜表面的吸附率要大得多,这是由于SiO2纳米粒子的比表面积大,表面活性位点多,且疏水性能强的缘故.     

基于微通道的ZnO纳米棒生物荧光检测研究

利用种子法和水热合成技术,分别在常规条件下和阵列式微通道中制备氧化锌(ZnO)纳米棒.采用扫描电子显微镜(SEM)、X射线衍射(XRD)等分析方法表征ZnO纳米棒的表面形貌特点和晶体结构.结果表明:微通道中制备的ZnO纳米棒的比表面积、结晶度和c轴取向性均有较大程度的提高.同时,建立了基于阵列式微通道的ZnO纳米棒生物荧光检测方法,利用ZnO纳米棒可显著增强荧光信号,对异硫氰酸荧光素标记的羊抗牛IgG抗体的检测限为1×10-4 μg/mL.     

金纳米粒子自组装过程的动力学研究

将三种不同粒径的金纳米粒子组装到经1,6-己二硫醇修饰的金表面,借助于石英晶体微天平(Quartz Crystal Balance,QCM)实时监测金纳米粒子的自组装动力学过程,结合Michaelis-Menten动力学模型,并比较了相应的自组装动力学参数,从而得出金纳米粒子粒径大小对金表面粒子组装动力学的影响.实验表明,粒径较小的粒子形成单分子层的速率比粒径较大的粒子快,而形成多分子层的速率比粒径较大的粒子慢.这一结果对合理选择粒子大小进而制成性能优良的生物传感器具有重要的意义.     

Cd2+掺杂SnO2纳米棒的制备与特性研究

在微乳液中SnCl和CdCl的混合水溶液与KBH4水溶液的还原反应制备了Cd2 掺杂SnO2纳米棒前驱物.在NaCl KCl熔盐介质中,660℃焙烧前驱成功制备了Cd2 掺杂SnO2纳米棒一维纳米材料.利用TEM、XRD、XPS和H2-TPR对SnO2纳米棒形貌、成分和材料表面氧吸附特性、H2还原特性进行了表征和分析.SnO2纳米棒直径为10nm～20 nm,长度从几百个纳米到几个微米,Cd2 掺杂后的SnO2纳米棒材料中CdO的含量可达5%.TPR的结果表明,Cd2 掺杂SnO2纳米棒表面吸附大量的氧具有较好的氧化还原特性.以SnO2纳米棒为原料,制备了厚膜气敏元件,考察了其H2敏感特性.     

金纳米颗粒制备及其光学特性研究

采用晶种生长法通过改变晶种对生长溶液的体积比例、引入离子合成了棒状和星形金纳米颗粒.首先用NaBH4作为还原剂制得小粒径球形金纳米颗粒作为晶种溶液,生长溶液中引入AgNO3为辅助试剂、溴化十六烷三甲基铵(CTAB)为表面活性剂来引导合成形貌不同的颗粒.对制备的球状、棒状和星状金纳米颗粒进行了紫外-可见光谱测试和表面增强...     

多壁碳纳米管-Nafion/纳米金构建阻抗传感器研究

利用多壁碳纳米管（ MWNT）—Nafion和纳米金（ GNPs）修饰金电极构建了一种简单、灵敏检测人端粒DNA的电化学阻抗传感器。首先将Nafion分散的MWNT滴涂于Au电极表面,再利用电化学沉积法将GNPs沉积到MWNT—Nafion修饰Au电极表面,以GNPs为载体固定人端粒探针DNA制备DNA传感器。在最优实验条件下,将传感器用于人端粒DNA的检测中,结果表明：目标人端粒DNA的线性范围为1.0×10－13～5.0×10－11mol/L,检出限（S/N＝3）为2.5×10－14mol/L。采用MWNT为基底沉积GNPs修饰电极检测的灵敏度显著提高。     

Sensing of lead ions using glutathione mediated end to end assembled gold nanorod chains

This communication reports the use of glutathione mediated self assembled chains of gold nanorods as new approach for the detection of Pb²⁺ ions. We were prompted to study the influence of metal ions by considering the role of glutathione as detoxification agent in the body. Additionally the ability of glutathione to complex with metal ions like lead (Pb²⁺) and mercury (Hg²⁺) is well known. We studied the interaction of different metal ions including Pb²⁺ with the end to end assembled chains of gold nanorods. Pb²⁺ was found to disassemble the chains to dimeric structures. High resolution transmission electron microscopy and dynamic light scattering were used to study the ensemble. A proportional reduction in the size of the assembly was observed between concentration ranges of 0.1-0.025 mM of Pb²⁺. Our results indicate that analyte induced disassembly is an attractive approach to the detection of environmentally relevant components such as Pb²⁺.     

Nanogaps formation and characterization via chemical and oxidation methods

Different materials were used to optimize the desired nano-size with smooth process and faster fabrication. Gold, polysilicon and silicon were used to apply this report (experimental). SOI and Si wafers have used as a substrate and one chrome mask to build up the nanogap devices using size reduction technique. Two chrome masks have used to fabricate the proposed pattern. Electrical characterization was applied to setup the fabricated devices with different materials. Conductivity and resistivity were measured to characterize the nanogap structure with gold, polysilicon and silicon as electrodes. However, gold nanogap has recorded an increment in the conductivity, and the silicon nanogap structures have recorded an increment in the resistivity comparing with the other used materials.     

Temperature-dependent microtensile testing of thin film materials for application to microelectromechanical system

A specially designed microtensile apparatus capable of carrying out a series of tests on microscale thin films for microelectromechanical system (MEMS) applications at room temperature and at temperature up to 400°C has been developed and tested, and is described here. Several MEMS-applicable thin films were measured with it, including thermally grown silicon dioxide, gold, and gold–vanadium. The silicon dioxide was tested at room temperature. Gold and gold–vanadium films were tested at room temperature and at 200 and 400°C. Examples of these results are presented.     

Tuning of the optical properties of the gold nanocluster ensemble formed in polytetrafluoroethylene film

Gold-filled polytetrafluoroethylene films with various gold concentrations were deposited in vacuum. Gold (Au) nanocluster size is increased with Au concentration elevation. Films were heated up to 300°C. Optical spectra were recorded during heating. The changes in Au plasmon band wavelength and shape during heating are not linearly related with Au concentration and heating temperature. This is caused by different thermal behaviour of the complex processes, which are taking place in each of the two materials presented in the film. The final Au cluster size and optical properties of the whole ensemble can be purposefully produced by varying Au concentration and annealing temperature of the film.     

Temperature-dependent microtensile testing of thin film materials for application to microelectromechanical system

A specially designed microtensile apparatus capable of carrying out a series of tests on microscale thin films for microelectromechanical system (MEMS) applications at room temperature and at temperature up to 400°C has been developed and tested, and is described here. Several MEMS-applicable thin films were measured with it, including thermally grown silicon dioxide, gold, and gold–vanadium. The silicon dioxide was tested at room temperature. Gold and gold–vanadium films were tested at room temperature and at 200 and 400°C. Examples of these results are presented.

     

Preparation of ZnO nanorods by microemulsion synthesis and their application as a CO gas sensor

Zinc oxide nanorods with different surface area were synthesized by surfactant assisted microemulsion method. The alkyl chain length of surfactant would affect aspect ratio of ZnO nanorods. ZnO nanorods synthesized by ethyl benzene acid sodium salt (EBS), which is surfactant with short alkyl chain length, show higher aspect ratio than ones by dodecyl benzene sulfonic acid sodium salt (DBS). These nanorods had diameters in the range of 80–300 nm and length of up to several microns. The Brunauer–Emmett–Teller (BET) surface area of the ZnO nanorods was strongly affected by the morphology of the nanorods. The BET surface area of the nanorods synthesized with EBS was higher than the surface area of the nanorods synthesized with DBS (20.2 and 14.1 m²/g for EBS and DBS, respectively). The response of ZnO nanorods to CO in air was strongly affected by surface area, defects and oxygen vacancies. The results demonstrate that the microemulsion synthesis is an easy and useful method to synthesize ZnO nanorods with large aspect ratio, which may enhance their gas sensing properties.