应用纳米金/TiO_2中空微球复合膜高灵敏检测转基因植物外源基因特定DNA序列

在碳糊电极表面制备的纳米金/TiO2中空微球复合膜可以极大地提高DNA检测的灵敏度.应用循环伏安法和电化学交流阻抗谱法研究了纳米金和TiO2中空微球在碳糊电极上的固载,并用[Fe(CN)6]3-/4-作为指示剂以电化学交流阻抗谱法表征了DNA的杂交.此DNA电化学生物传感器成功检测了来自于花椰菜花叶病毒的35S启动子基因的DNA特定序列,其动力学检测范围为1.0×10-12~1.0×10-8mol/L,检测限为2.3×10-13mol/L;同时对从一种转基因大豆中提取的外源基因胭脂碱合成酶基因终止子的聚合酶链式反应(PCR)扩增产物进行了检测,得到了满意的结果.     

应用纳米金／TiO2中空微球复合膜高灵敏检测转基因植物外源基因特定DNA序列

在碳糊电极表面制备的纳米金／TiO2中空微球复合膜可以极大地提高DNA检测的灵敏度．应用循环伏安法和电化学交流阻抗谱法研究了纳米金和TiO2中空微球在碳糊电极上的固载,并用[Fe（CN）6]^3-/4-作为指示剂以电化学交流阻抗谱法表征了DNA的杂交．此DNA电化学生物传感器成功检测了来自于花椰菜花叶病毒的35S启动子基因的DNA特定序列,其动力学检测范围为1．0×10^-12～1．0×10^-8mol／L。检测限为2．3×10^-13mol／L;同时对从一种转基因大豆中提取的外源基因胭脂碱合成酶基因终止子的聚合酶链式反应（PCR）扩增产物进行了检测,得到了满意的结果．     

基于纳米ZnO/壳聚糖复合膜DNA电化学传感器用于HIV基因的免标记检测

以室温固相合成法制备纳米ZnO,通过壳聚糖(CHIT)的成膜效应将纳米ZnO固定在玻碳电极(GCE)表面,制得的ZnO/CHIT/GCE电极成为DNA固定和杂交的良好平台。DNA的固定和杂交通过电化学交流阻抗进行表征。以电化学交流阻抗免标记法检测目标DNA,固定于电极表面的DNA探针与目标DNA杂交后使电极表面的电子传递电阻增大,以此作为检测信号可以高灵敏度地测定目标DNA。电化学阻抗谱检测人类免疫缺陷病毒(HIV)基因片段的线性范围为2.0×10-11~2.0×10-6mol/L,检出限为2.0×10-12mol/L。     

硒化铅纳米粒子DNA电化学传感器检测花椰菜花叶病毒35S启动子基因序列

以水热法合成十六烷基三甲基溴化铵(CTAB)修饰的PbSe纳米粒子。在碳糊电极表面制备的PbSe纳米粒子壳聚糖(CHIT)复合膜上,实现了DNA的固定和杂交,并用循环伏安法和电化学交流阻抗法进行了表征。应用电活性分子亚甲紫(MV)作为杂交指示剂,以微分脉冲伏安法对转基因植物CaMV35S启动子基因片段进行测定,检测范围为5.0×10-11～5.0×10-6mol/L;检出限为1.6×10-11mol/L(3σ)。该传感器能很好地识别DNA互补序列、非互补序列和2碱基错配序列。     

氟嗪酸在碳纳米管修饰电极上的电化学行为及含量的测定

在玻碳电极上制备了多壁碳纳米管/Nafion(MWNTs-Nafion)膜,用交流阻抗谱(EIS)、循环伏安法(CV)、线性扫描伏安法(LSV)研究了氟嗪酸在该膜上的电化学行为。与裸玻碳电极相比,这种纳米结构膜修饰的电极对氟嗪酸的电化学氧化显现出极好的促进作用,氟嗪酸的氧化峰电流明显增强,在修饰电极上于 0.97 V处产生了1个灵敏氧化峰。LSV测定氟嗪酸的线性范围为1.0×10-8～1.0×10-6mol/L和1.0×10-6～2.0×10-5mol/L,开路富集400 s后,检出限为8.0×10-9mol/L(3倍信噪比),方法可用于人尿中氟嗪酸的实时测定。     

基于多壁碳纳米管和纳米金修饰电极测定特殊序列DNA的电化学生物传感器的制备

基于多壁碳纳米管和纳米金复合膜修饰电极制备了特殊序列的靶DNA的电化学生物传感器.该传感器以六氨基合钌为杂交指示剂,用差示脉冲伏安法进行检测DNA杂化,其响应信号与靶DNA浓度在1.0×10<'-12>～1.0×10<'-7>mol/L范围内呈线性关系,检测限达3.5×10<'-13>mol/L.该传感器能区分单碱基错配的靶DNA.     

基于纳米MnO2的免标记型DNA电化学生物传感器用于大肠杆菌的测定

以室温固相合成法制备纳米MnO2,通过壳聚糖（CHIT）的成膜效应将纳米MnO2固定在玻碳电极表面。DNA在MnO2/CHIT膜上的固定和杂交通过循环伏安和电化学交流阻抗进行表征。以电化学阻抗免标记法检测目标DNA,固定于电极表面的DNA探针与目标DNA杂交后使电极表面的电子传递电阻增大,以此作为检测信号可以高灵敏度地测定目标DNA。电化学阻抗谱检测大肠杆菌基因片段的线性范围为2.0&#215;10^-11 ～2.0&#215;10^-6mol/L,检出限为1.0&#215;10^-12mol/L。     

氧化铜/还原氧化石墨烯-多壁碳纳米管复合膜电极检测L-酪氨酸

采用水合肼原位化学还原法制备了还原氧化石墨烯(rGO)-多壁碳纳米管(MWCNTs)复合物,将该复合物滴涂于玻碳电极表面,通过电化学方法向该复合膜表面沉积了纳米氧化铜(CuO),制得氧化铜-还原氧化石墨烯-多壁碳纳米管三元复合物修饰电极(CuO-rGO-MWCNTs/GCE)。通过扫描电镜、EDS能谱及电化学交流阻抗技术对该电极进行了表征。研究了L-酪氨酸(L-Tyr)在该修饰电极上的电化学行为。结果表明,CuO-rGO-MWCNTs/GCE对L-Tyr的电氧化表现出高的催化活性。在优化实验条件下,安培法检测L-Tyr的线性范围为2.0×10~(-8)~1.8×10~(-4)mol/L,检出限为5.0×10~(-9)mol/L(S/N=3)。     

以碳纳米管为支撑电沉积制备高电活性与电催化性能的六氰合铁酸钴纳米多孔薄膜

以碳纳米管(MWNTs)修饰的碳糊电极为基底电极,通过电沉积方法制备了六氰合铁酸钴(CoHCF)纳米多孔生物传感平台。考察了MWNTs对CoHCF沉积的影响,优化了CoHCF沉积的各种实验条件(0.5mol/L KCl,1 mmol/L CoCl2和0.9 mmol/L K3Fe(CN)6混合溶液,在循环伏安电压范围0～1.1 V内扫20圈,扫速100 mV/s),借助循环伏安法、交流阻抗法和扫描电镜法对修饰电极进行了表征。由于MWNTs的支撑作用,电沉积得到的CoHCF呈现出多孔结构和良好的电化学稳定性。具有纳米多孔结构的MWNTs-CoHCF薄膜能有效地促进生物小分子在电极上的电子交换,维生素B2在纳米多孔CoHCF/MWNTs上具有优异的氧化还原行为,其测定线性范围为1.2×10-7～2.6×10-7mol/L,检出限为8.9×10-8mol/L。     

镍纳米粒子修饰碳糊电极直接电催化鸟嘌呤的研究

将镍纳米粒子与石蜡、石墨按照一定比例混合制备镍纳米粒子修饰碳糊电极,采用循环伏安法(CV)对修饰碳糊电极进行电化学表征,在0.1 mol/L B-R缓冲溶液(pH4.5)中研究了鸟嘌呤在该修饰电极上的电化学行为。结果表明,与裸碳糊电极相比,以掺杂法制备的镍纳米粒子修饰电极能够明显降低鸟嘌呤的过电位,增大其氧化电流,很好地催化氧化鸟嘌呤。在优化的实验条件下,鸟嘌呤在该修饰电极上的氧化峰电流与其浓度在1.0×10-5~5.0×10-4mol/L范围内呈良好的线性关系,检出限(3σ)为7.5×10-6mol/L。     

纳米碳管作为氧扩散电极催化层第二相碳载体的电极特性

A novel gas diffusion electrode using binary carbon supports (carbon nanotubes and active carbon) as the catalyst layer was prepared. The electrochemical properties for oxygen reduction reaction (ORR) in alkaline electrolyte were investigated by polarization curves and electrochemical impedance spectroscopy. The results show that the binary-support electrode exhibits higher electrocatalytic activity than the single-support electrode, and the best performance is obtained when the mass ratio of carbon nanotubes and activated carbon is 50 ∶50. The results from their electrode kinetic parameters indicate that the introduction of carbon nanotubes as a secondary support provides high accessible surface area, good electronic conductivity and fast ORR kinetics. The electrocatalytic activity of binary-support electrodes is obviously improved by the deposition of Pt nanoparticles on carbon nanotubes, even at very low Pt loading (45.7 μg/cm2). In addition, the EIS analysis results show that the process of ORR may be controlled by diffusion of oxygen in the thin film for binary-support electrodes with or without Pt catalyst.     

Direct electrochemistry and electrocatalysis of horseradish peroxidase immobilized in hybrid organic-inorganic film of chitosan/sol-gel/carbon nanotubes

A hybrid organic-inorganic nanocomposite film of chitosan/sol-gel/multi-walled carbon nanotubes was constructed for the immobilization of horseradish peroxidase (HRP). This film was characterized by scanning electron microscopy. Direct electron transfer (DET) and bioelectrocatalysis of HRP incorporated into the composite film were investigated. The results indicate that the film can provide a favorable microenvironment for HRP to perform DET on the surface of glassy carbon electrodes with a pair of quasi-reversible redox waves and to retain its bioelectrocatalytic activity toward H₂O₂.     

石墨烯/碳纳米管复合薄膜的制备进展

石墨烯/碳纳米管复合材料具有石墨烯和碳纳米管的共同特性,它弥补了石墨烯不连续和碳纳米管网存在间隙这两方面缺点。 本文探讨了石墨烯/碳纳米管复合薄膜的制备新进展,阐述了利用自组装合成、非原位合成以及非化学合成等方法制备厚度薄、强度高和比电容高等特点的石墨烯/碳纳米管复合薄膜的方法,对石墨烯/碳纳米管复合薄膜在传感器、锂电池和超级电容器等方面的应用前景进行了展望。     

Nickel oxide coated on ultrasonically pretreated carbon nanotubes for supercapacitor

Nickel oxide/carbon nanotubes (NiO/CNTs) composite materials for supercapacitor are prepared by chemically depositing nickel hydroxide onto carbon nanotubes pretreated by ultrasonication and followed by thermal annealing at 300 °C. A series of NiO/CNTs composites with different weight ratios of nickel oxide versus carbon nanotubes are synthesized via the same route. The high-resolution TEM and SEM results show that a lot of nicks, which favored the nucleation of the nickel hydroxide formed on the outer walls of carbon nanotubes due to ultrasonic cavitations, and then nickel oxide coated uniformly on the outer surface of the individual carbon nanotubes. The NiO/CNTs electrode presents a maximum specific capacitance of 523 F/g as well as a good cycle life during 1,000 cycles in 6 M KOH electrolyte. The good electrochemical characteristics of NiO/CNTs composite can be attributed to the three-dimensionally interconnected nanotubular structure with a thin film of electroactive materials.     

原位化学沉积法制备碳/聚苯胺复合材料作为超级电容器材料的研究

Polyaniline （PA） film was chemically deposited onto the surface of activated carbon （AC） uniformly. Chemical deposition was carried out in 0.1 mol/L aniline plus 0.5 mol/L H2SO4 solution adopting V2O5·nH2O coated on the surface of activated carbon as oxidant. The surface morphologies and structures of the composite materials were characterized by scanning electron microscopy and FT-IR spectra. The electrochemical properties of the composite material electrodes were studied by cyclic voltammetry and constant current charge/discharge tests in 1 molFL H2SO4 solutions. The specific capacitance of composite materials was exhibited as high as 237.5 F/g at a current density of 1.0 A/g compared with a value of 120 F/g for pure carbon electrode. Good power characteristic and good stability of composite electrodes were also demonstrated.     

镧掺杂的二氧化锰/碳纳米管电化学超级电容器复合电极

尽管在二氧化锰/多壁碳纳米管（MnO₂/MWCNTs）上获得了较高的比电容,低电导率仍是制约MnO₂担载量或膜厚度提高的主要障碍.另一个问题是MnO₂/MWCNTs的循环稳定性远低于活性炭.所以截止到目前这一新型材料的应用仍然受到很大的限制.本文采用原位还原的方法制备镧掺杂二氧化锰/多壁碳纳米管电化学超级电容器复合电极材料.分别通过透射电镜（TEM）、扫描电镜（SEM）、X射线衍射（XRD）和傅里叶变换红外（FTIR）光谱等技术对这些复合材料的形貌与结构进行了分析.采用循环伏安法、恒电流充放电法和交流阻抗法对其进行了电化学性能的研究.研究结果表明,通过还原MnO₄^-可以在MWCNTs上形成La掺杂MnO₂复合材料.La掺杂降低了复合电极的电阻,这是因为La的引入可以增大MnO₂的晶格缺陷,从而提高材料的电导率以及电极的电化学性能.因此La掺杂是克服MnO₂本征导电性差的有效途径之一.掺杂La可以在不增大电极电阻的情况下提高MnO₂的担载量或膜厚度.La掺杂的更重要的作用是使以MnO₂/MWCNTs作电极的对称电化学超级电容器的循环性能得到显著改善.此外,La掺杂也使复合电极的比电容得到一定程度的提高.     

Atomic Force Microscopic and Electrochemical Investigations of an Electrostatically Fabricated Single‐Wall Carbon Nanotubes Modified Electrode

Single‐wall carbon nanotubes (SWNTs) sub‐monolayer film has been prepared by simply electrostatically adsorbing nanotubes onto a 2‐aminoethanethiol self‐assembled monolayer (SAM) on a gold bead electrode. Tapping‐mode atomic force microscopy (TM‐AFM) is used to characterize the SWNT film, which exhibits that the orientation of SWNTs on the SAM is horizontal and the surface coverage is quite low. The SWNTs modified electrode shows nearly ideal electrochemical response to Fe(CN) /Fe(CN) redox probe. The electrode with such a low SWNTs coverage, however, shows good electrocatalytic behavior to cytochrome c.     

纳米碳管表面羧基化及其电还原性能

应用红外吸收光谱、扫描电子显微镜分别对纳米碳管和硝化后的纳米碳管进行表征,将其制备成粉末微电极,并在碱性溶液中测试它对对硝基苯酚的电还原性能.实验表明:经硝化处理后,碳管表面修饰了羰基,其电还原性能明显提高.依据实验结果探讨了硝化后纳米碳管于对硝基苯酚电还原过程中的反应机理.     

Carbon Nanotubes/Poly(1,2‐diaminobenzene) Nanoporous Composite Film Electrode Prepared by Multipulse Potentiostatic Electropolymerisation and Its Application to Determination of Trace Heavy Metal Ions

A novel method for the fabrication of carbon nanotubes/poly(1,2‐diaminobenzene) nanoporous composite based electrode was proposed. By multipulse potentiostatic electropolymerization, the multi‐walled carbon nanotubes (MWNTs) and poly(1,2‐diaminobenzene) were deposited simultaneously on the electrode surface. Compared with the composite prepared by the traditional potentiodynamic method, the composite synthesized by multipulse potentiostatic method has a unique nanoporous structure, exhibits excellent conductivity and better environmental stability. The surface of the resulting electrode was characterized with scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The nanoporous composite film modified glassy carbon electrode was also used successfully for the simultaneously voltammetric determination of trace level of Cd²⁺ and Cu²⁺ at first‐time. Under the optimal conditions, the determination limits of 0.25 and 0.33 ppb for Cd²⁺ and Cu²⁺ were obtained, respectively. The calibration graphs were linear in the concentration range of 5–100 ppb. The electrode system provides an excellent platform for ultra sensitive electrochemical sensors for chemical and biological sensing.     

聚邻氨基苯甲酸-铜复合薄膜修饰电极的制备及其电化学性能

利用聚合物官能团对金属离子的配位作用,在电极表面原位制备了金属粒子。 首先在玻碳电极（GCE）表面电沉积聚邻氨基苯甲酸(PoABA),再化学吸附铜离子(Cu2+),用水合肼还原得到单质铜(Cu0)。 采用扫描电子显微镜和能谱分析表征了聚邻氨基苯甲酸 铜(PoABA-Cu0)复合薄膜的表面形貌和元素构成,研究了PoABA-Cu0修饰电极的电化学性能,并以其检测了过氧化氢（H2O2）。 结果表明,电极表面被修饰上了一层PoABA-Cu0复合薄膜;制备的修饰电极对H2O2具有良好的电催化性能,在邻氨基苯甲酸的聚合圈数为10、Cu2+的吸附时间为10 min、工作电压为-0.3 V时,该修饰电极对H2O2表现出了最佳的检测性能,其线性浓度范围为5.0×10-5～1.0×10-2 mol/L,灵敏度为96.3 μA·L/(mmol·cm),检测限为5.0×10-5 mol/L,且具有较好的稳定性。