PVP／CdS量子点修饰电极的制备及其对肌红蛋白的直接电化学研究

该文采用溶胶-凝胶法制备了聚乙烯吡咯烷酮(PVP)表面修饰的硫化镉(CdS)半导体量子点,用透射电镜(TEM)、X射线衍射(XRD)等手段进行了表征;将其修饰在玻碳电极(GC)表面制得量子点修饰电极,并研究了肌红蛋白(Myoglobin,Mb)在该量子点修饰电极上的电化学行为.实验结果表明,PVP/CdS量子点修饰电极对肌红蛋白具有催化还原作用,且还原峰电流与被测蛋白质浓度呈良好线性关系.流动注射分析结果进一步表明该量子点修饰电极具有高的稳定性和好的重现性,检出限为2.0×10.mol/L,该电极可作为检测肌红蛋白的新型高灵敏度电化学传感器.     

基于CdTe量子点-壳聚糖-石墨烯纳米复合物构建亚硝酸盐电化学传感器

构建了一种基于CdTe量子点-壳聚糖-石墨烯纳米复合物修饰玻碳电极的亚硝酸盐电化学传感器,壳聚糖作为连接剂,CdTe量子点静电自组装负载到石墨烯上,外层包覆的聚乙烯吡咯烷酮(PVP)薄层用于稳定修饰物.对该传感器进行了电化学表征该电极,并与差分脉冲伏安法结合用于检测亚硝酸盐,该传感器在2 μmol/L~100 μmol/L范围内具有良好的线性关系,检出限为0.89 μmol/L,加标回收率在96.7%~101.8%内.该传感器具有灵敏度高、检出限低、准确、快速等优势,应用到市售腌菜中亚硝酸盐的检测,结果令人满意.     

DNA-碳纳米管／聚苯胺复合膜选择性测定多巴胺

构建了DNA-碳纳米管/聚苯胺复合膜修饰的玻碳电极,研究了抗坏血酸(AA)存在下多巴胺(DA)在该修饰电极上的电化学行为,发现DNA-碳纳米管/聚苯胺复合膜对多巴胺有明显的电催化作用.在0.1mol/L磷酸缓冲溶液(pH7.0)中,用方波伏安法(SWV)测得氧化峰电流与DA浓度在0.1～30×10-5mol/L范围内呈良好的线性关系.该修饰电极用于样品DA的检测,结果满意.     

基于CdTe／CdS量子点与金纳米粒子的荧光共振能量转移测定三聚氰胺

量子点具有良好的光学性能和高的光致发光量子产率,已广泛应用于生物分析。该文利用金纳米粒子（AuNPs）与CdTe／CdS量子点相互作用,发生荧光共振能量转移（FRET）而猝灭Cdrre／CdS量子点的荧光．加入三聚氰胺后使量子点的荧光恢复这一现象,建立了一种基于CdTe／CdS量子点与AuNPs的FRET测定三聚氰胺的高灵敏方法。     

基于Nafion-石墨烯复合物固定甲胎蛋白电化学免疫传感器的研究

该文利用Nation-石墨烯复合物和纳米金固定甲胎蛋白抗体(anti-AFP),构建了高灵敏的电化学免疫传感器.首先将石墨烯分散在Nation溶液中制得Nation-石墨烯的复合膜,并将其固定在玻碳电极(GCE)表面,通过静电吸附和共价键合作用将硫堇(Thi)和纳米金颗粒(nano-Au)依次固定到Nation-石墨烯复合膜修饰的玻碳电极表面.再通过纳米金单层吸附anti-AFP,最后用牛血清蛋白(BSA)封闭电极上的非特异性吸附位点,从而制得了甲胎蛋白免疫传感器.实验结果表明,该修饰电极对不同浓度的甲胎蛋白(AFP)有很好的响应,其线性范围为0.8～100 ng/mL,检出限为0.36 ng/mL.     

基于RGD多肽掺杂聚吡咯-铟锡氧化物的仿生微电极构建及用于细胞生物学行为的电化学阻抗谱检测

构建一种基于RGD多肽分子掺杂聚吡咯膜修饰的铟锡氧化物微电极(PPy/RGD-ITO),并以此作为传感电极实现细胞生物学行为的电化学阻抗谱检测.采用光刻技术蚀刻感光干膜绝缘层制备ITO微电极;以含RGD模体的多肽分子作为吡咯电聚合唯一的掺杂阴离子,通过电化学共聚合方式在ITO微电极表面沉积PPy/RGD复合膜形成PPy/RGD-ITO微电极;原子力显微镜(AFM)、接触角测量仪和傅里叶变换红外光谱仪(FTIR)分别表征PPy/RGD复合膜的表面拓扑形貌、湿润性和组成成分;人肺癌细胞株A549铺展、粘附及增殖实验考察了PPy/RGD复合膜与细胞间的相互作用;以构建的PPy/RGD-ITO微电极作为传感电极,通过电化学阻抗谱技术对A549细胞粘附增殖行为及天然抗癌药物分子重楼皂苷I的细胞毒性进行了分析.结果显示,通过简单的电化学共聚合成功将RGD分子掺杂进PPy膜内,且PPy/RGD复合膜具有优异的表面物理性能;PPy基质膜内掺杂的RGD分子保留其生物活性,相比裸ITO电极和聚4-苯乙烯磺酸钠(PSS)掺杂的PPy膜,PPy/RGD复合膜能更好地促进A549细胞的铺展、粘附和增殖;由于PPy/RGD-ITO微电极表面A549细胞形态学变化可改变电极系统的阻抗谱特征,因此通过电化学阻抗谱技术可解析A549细胞粘附增殖行为学信息,同时可定量分析重楼皂苷I细胞毒性.因此,通过简单的电化学共聚合方法将生物活性RGD分子掺杂进PPy膜内制备出的PPy/RGD膜具有优良的生物相容性,可作为一种重要的仿生电极修饰材料用于构建电子系统和细胞生物学系统的耦合界面,未来可应用于细胞生物学行为及药物筛选研究.     

基于特殊形貌CdS纳米颗粒修饰的DNA传感器在DNA杂交信号检测中的应用

用水热法制备出具有特殊核桃状外表的纳米小球修饰在玻碳电极的表面,通过5′端巯基修饰的探针DNA共价结合在CdS层敏感层上形成共聚物,再与靶DNA杂交,利用循环伏安法(CV)和差分脉冲伏安法(DPV)研究修饰电极的电化学行为。修饰CdS纳米颗粒的电极检测得到的DNA杂交信号有明显的增强,峰电流强度值与靶DNA浓度值的负对数具有较好的线性关系,信号增强的最大值在靶DNA浓度为101μmol/L时得到。传感器灵敏度提高,检测下限可达1pmol/L以下。     

一种新的多层碳纳米管复合膜修饰的葡萄糖生物传感器制备

将碳纳米管(CNT)分散在壳聚糖(CHIT)溶液中固定到玻碳电极表面,用戊二醛交联甲苯胺蓝(TB)得到复合膜(TB-CNT-CHIT)修饰电极.由于碳纳米管具有良好的电子传递性能,与碱性生物染料甲苯胺蓝之间表现出协同作用,使甲苯胺蓝的电化学活性得到了较大的提高.此TB-CNT-CHIT复合膜修饰的玻碳电极在较低电位下对过氧化氢具有良好的电催化性能,与TB-CHIT膜比较,测定H2O2的灵敏度增大了近20倍.将复合组份多层修饰到电极上,通过戊二醛固定葡萄糖氧化酶,制备了一种新的葡萄生物传感器,该传感器在-0.2 V下对葡萄糖响应的线性范围为0.05～10 mM,检测下限为10μM.传感器的灵敏度较高,响应快,性能稳定.     

纳米银/ds-DNA/聚（3,4-乙烯基二氧噻吩）复合膜修饰电极的制备及应用于过氧化氢无酶传感器

在室温水相中,通过电化学方法在玻碳电极上先聚合了聚（3, 4-乙烯基二氧）噻吩（PEDOT）,然后又电沉积了双链DNA（ds-DNA）和银纳米粒子（Nano-Ag）,制备了Nano-Ag/ds-DNA/PEDOT复合膜修饰玻碳电极（GCE）。对该复合膜进行了表征,并研究了该复合膜修饰电极的电化学行为以及对过氧化氢（H2O2）的电催化还原。结果显示,施加工作电位为-0.3 V时,修饰电极对H2O2有着很好的电催化还原能力,达到稳态电流的响应时间小于5 s。因此,该修饰电极可作为无酶传感器用于对H2O2的快速检测。传感器的催化还原电流与H2O2浓度在10 μM-16 mM范围内呈现良好的线性关系,检出限为2.36 μM（S/N=3）。     

基于EDTA蚀刻的CdTe/CdS量子点荧光探针 检测水环境中痕量镉离子

设计了一种基于乙二胺四乙酸(EDTA)蚀刻的“关－开”模式的CdTe/CdS核壳量子点(QDs)的荧光传感器,具有高灵敏,高选择性,快速检测水环境中痕量Cd2+的优点,EDTA通过在 CdTe/CdS QDs表面进行化学蚀刻,使CdTe/CdS QDs表面的Cd2+流失而和EDTA络合,在QDs表面形成空穴,得到特定的Cd2+识别位点,从而导致荧光猝灭,Cd2+的引入可以选择性的识别这些位点,使得EDTA-QDs体系的荧光恢复。在优化的工作条件下,该荧光传感器的线性响应范围为10μg/L~ 200μg/L和300μg/L~1000μg/L,实现了Cd2+在较大范围的测定要求,线性相关系数分别为0.997、0.985,检出限为0.22μg/L(0.002μmol/L),达到了国家二类水质标准(GB/T 14848-93)对Cd2+的检出限要求。此外,该荧光传感器对其他干扰离子的选择性优于1％,在实际水样检测中具有良好的实用性。     

A dissolved oxygen sensor based on hot electron induced cathodic electrochemiluminescence at a disposable CdS modified screen-printed carbon electrode

Hot electron induced cathodic electrochemiluminescence (ECL) was found at a disposable CdS modified screen printed carbon electrodes (CdS-SPCEs) during cathodic pulse polarization. The ECL behavior of the modified electrode was investigated with two emissions located at 520 nm and 580 nm. The CdS-SPCEs show very stable and reproducible ECL signal. The ECL intensity was linear with the dissolved oxygen concentration in the range of 1.7-33 mg/L with a detection limit of 0.02 mg/L (S/N = 3). In addition, a possible mechanism for ECL behavior of the modified electrode was proposed. The developed method can be applied to detect the dissolved oxygen concentration or biochemical oxygen demand (BOD).     

Electrogenerated chemiluminescence sensor for itopride with Ru(bpy)3-doped silica nanoparticles/chitosan composite films modified electrode

A electrogenerated chemiluminescence (ECL) sensor for itopride was developed based on tris(2,2-bipyridyl)ruthenium(II) (Ru(bpy)₃²⁺)-doped silica (RuDS) nanoparticles/biopolymer chitosan composites membrane modified glassy carbon electrode (GCE). The RuDS nanoparticles (52 ± 5 nm) were prepared by a modified Stőber synthesis method and were characterized by electrochemical, fluorometric and transmission electron microscopy technology. The Ru(bpy)₃²⁺ encapsulation interior of the silica nanoparticle maintains its electrochemical activities and also reduces Ru(bpy)₃²⁺ leaching from the silica matrix when immersed in water due to the electrostatic interaction. The ECL analytical performances of this ECL sensor for itopride based on its enhancement ECL emission of Ru(bpy)₃²⁺ were investigated in details. Under the optimum condition, the enhanced ECL intensity was linear with the itopride concentration in the range of 1 × 10⁻⁸ to 2 × 10⁻⁵ g/mL (R = 0.9978). The detection limit was 3 × 10⁻⁹ g/mL, and the relative standard deviation was 2.3% for 8 × 10⁻⁸ g/mL itopride (n = 11). The method was successfully applied to the determination of itopride in pharmaceutical and human serum samples with satisfactory results. The as-prepared ECL sensor for the determination of itopride displayed good sensitivity and stability.     

Electrochemiluminescence quenching via capture of ferrocene-labeled ligand-bound aptamer molecular beacon for ultrasensitive detection of thrombin

Herein, we present an ultrasensitive protein-detection protocol based on electrochemiluminescence (ECL) quenching through capture of ferrocene-labeled ligand-bound aptamer molecular beacon (MB). Our device included two main parts: a solid-state ECL sensing platform and an ECL switch. The sensing platform was constructed by modifying the composite of tris(2,2′-bipyridyl) ruthenium(II) and platinum nanoparticles (Ru-PtNPs) and followed by immobilization of capture DNA (CaDNA). MB worked as the ECL intensity switch. In the presence of thrombin (TB), the hairpin-shaped MB binded to TB, inducing the exposure of a partial single-strand (MBs at this state was ligand-bound MBs). The exposed single stand was complementary to CaDNA and hybridized with CaDNA, leading to the capture of ligand-bound MB onto ECL sensing platform and finally resulting in ECL quenching by ferrocene that linked to MB. Otherwise, the ligand-unbound MB could not be captured and ECL quenching would not happen. Accordingly, the change of ECL intensity indirectly reflected the concentration of TB in the sample. The results indicated that our protocol realized recognition of TB directly in the solution and exhibited much higher sensitivity with a detection limit of 1.7 pM. Thus, this approach would be a promising protein-detection procedure directly performed in the solution.     

基于核酸适体和纳米材料构建电化学生物传感器用于多巴胺的检测

该文探究了一种基于核酸适体和纳米金包四氧化三铁（Au@Fe,041纳米粒子所构建的新型电化学生物传感器用于多巴胺（DA）的检测。首先,在玻碳电极（GCE）表面电沉积一层纳米金（nano—Au）用于多巴胺适体（DBA）的固定。然后HT做为封闭剂以减少非特异性吸附。接着通过与DBA的特异性结合将DA固载于电极表面。在EDC／NHS作用下,生物素（Bio）的羧基与DA的氨基结合,最后通过生物素与亲和素特异性识别作用将含有电化学活性物质硫堇的纳米复合材料固定于电极表面,制得夹心型的适体传感器。在最优条件下．该传感器对0．001nmol／L-100nmol／LDA的检测具有良好的电流响应,检出限0．33pmol／LfS／N=31。该适体传感器具有操作简单、操作简便、选择性好、灵敏度高、检测范围广、检出限低的优点。     

基于碳纳米管固定葡萄糖氧化酶的ECL葡萄糖传感器的制备

将葡萄糖氧化酶(GOD)固定在多壁碳纳米管(MWCNTs)修饰电极(ME)上,GOD催化氧化葡萄糖生成过氧化氢,并使鲁米诺产生电致化学发光(ECL),据此构建了一种新型ECL葡萄糖传感器.结果表明:CNTs修饰的电极对鲁米诺和H2O2反应具有显著的电催化活性和增敏效果.该传感器对葡萄糖检测的线性范围为0.01～10.0...     

基于NaOH刻蚀玻碳电极的电化学传感器在检测膀胱癌DNA中的应用

制备了一种基于活化的玻碳电极的新型电化学DNA生物传感器,可用于膀胱癌DNA的检测.通过循环伏安法(CV)实现玻碳电极在NaOH溶液中的刻蚀,使电极表面负载大量官能团,为DNA提供连接位点,由Laviron方程计算得到玻碳电极表面的羧基浓度为 1.022×10-6 mol/cm2.亚甲基蓝(MB)作为电化学检测的杂交指示剂.采用原子力显微镜(AFM)对刻蚀后的电极进行了形貌表征.在最优杂交条件下,通过差分脉冲法(DPV)计算出最佳检测限为5.677×10-13 mol/L(n=5),适用目标 DNA浓度范围1×10-8 mol/L~1×10-12 mol/L.该传感器有望用于实际样品中膀胱癌DNA的快速检测.     

Direct electron transfer of myoglobin in mesoporous silica KIT-6 modified on screen-printed electrode

A disposable hydrogen peroxide biosensor was developed based on the direct electron transfer of myoglobin (Mb) on mesopores KIT-6 modified screen-printed electrode (SPE) which was manually performed to fabricate the planar carbon electrodes. KIT-6 is a new material which can absorb abundant of Mb molecules. A mixture of Mb and KIT-6 was immobilized with nafion on electrode. The cyclic voltammetry experiment indicated that a pair of stable and well-defined reduction peaks with a formal potentials of −0.35, and −0.28 V versus saturated calomel electrode (SCE) was obtained, using the present modified electrode in phosphate buffer saline (0.05 M, pH 7.0) at scan rate of 100 mV s⁻¹, characteristic of Mb heme Fe(III)/Fe(II) redox couple. The heterogeneous electron transfer rate constant k_s was estimated to be 16.93 s⁻¹. And the formal potential was pH-dependent, having two slopes of −54.7 and −49.3 mV/pH which illustrated one electron transfer. This modified electrode was applied to detect H₂O₂ with sensitivity of 55.68 mA M⁻¹ cm⁻². Infrared spectrum and UV–vis absorption spectra of immobilized Mb film were recorded. In conclusion, KIT-6 increases the electron transfer activity of Mb and this kind of H₂O₂ biosensor is low cost for using disposable.     

电化学发光免疫传感器检测相思子毒素研究

以磁性微球固定相思子毒素多抗制备捕获探针,以三联吡啶钌标记相思子毒素单抗作为发光探针,两者与相思子毒素发生特异性免疫反应形成夹心复合物,成功建立了相思子毒素的电化学发光免疫传感检测方法。利用此方法检测相思子毒素,浓度在0.1～1000μg/L范围内与电化学发光强度呈良好的对数线性关系,拟合方程为lg Y=0.763 lg X+0.562(R=0.9903,N=7,P<0.0001),检出限为0.1μg/L。     

Electrochemical studies of bovine serum albumin immobilization onto the poly-o-phenylenediamine and carbon-coated nickel composite film and its interaction with papaverine

A biosensor based on bovine serum albumin (BSA) and poly-o-phenylenediamine (PoPD)/carbon-coated nickel (C-Ni) nanobiocomposite film modified electrode has been developed to study the interaction of BSA with papaverine (PAP). The well-dispersed C-Ni nanoparticles were dripped onto the glassy carbon electrode (GCE) surface firstly, and PoPD films were subsequently electropolymerized by cyclic voltammetry (CV) to prepare PoPD/C-Ni/GCE. Finally, the BSA was easily immobilized on the PoPD films via electrostatic adsorption. The morphology and the electrochemical properties of the fabricated composite electrodes were examined by scanning electron microscope (SEM) and electrochemical impedance spectroscopy (EIS), respectively. The interaction of PAP with BSA was monitored by differential pulse voltammetry (DPV), using PoPD as the electrochemical indicator. The binding constant (K), obtained by DPV, was 1.7 × 10⁴ L/mol, which was consistent with the fluorescence analysis. This constructed biosensor also exhibited a fine linear correlation with PAP concentration range of 2.5 × 10⁻⁹-4.5 × 10⁻⁵ mol/L and a detection limit of 8.3 × 10⁻¹⁰ mol/L was achieved by DPV.