结核分枝杆菌分泌蛋白抗原免疫电化学检测方法的建立

目的建立一种新型、快速的结核分枝杆菌(Mycobacterium tuberculosis,MTB)分泌蛋白抗原85B(Ag85B)免疫电化学检测方法。方法先在玻碳电极(Glassy carbon electrode,GCE)表面电沉积一层纳米金,通过静电吸附固定普鲁士蓝壳聚糖(Chitosan-prussian blue,CS-PB)纳米复合物,利用壳聚糖的氨基功能团固定微米金磁微粒(Au-Fe3O4),再吸附兔抗Ag85B多克隆抗体,制得电流型免疫传感器。测定电极制备过程的电化学特征,通过原子力显微镜对免疫传感器进行表征,确定免疫传感器的最佳pH值、反应时间、检测线性响应范围及检测下限,验证该方法的特异性和重复性,并与ELISA检测结果进行比较。结果原子力显微镜结果表明,Au-Fe3O4与兔抗Ag85B多克隆抗体可连接到电极表面。在最佳pH值(pH7.5)和反应时间(12min)的条件下,该传感器响应的峰电流值与Ag85B浓度在10～500ng/ml的范围内呈良好的线性关系,检测下限可达10ng/ml,且具有良好的特异性和重复性。免疫传感器与ELISA检测结果的吻合性较好。结论已成功制备了检测Ag85B的免疫传感器,该传感器制备简单,操作便捷,灵敏度高。     

基于Au纳米材料的电化学标记免疫传感器研究

利用Au-S键的强烈吸附特性以及金纳米粒子对蛋白质的吸附特性,以硫堇为电化学标记物,通过抗体、抗原的生物吸附性,构筑三明治结构的电化学免疫夹心传感器。在磷酸缓冲溶液(pH=7.4)中,用循环伏安法(CV)与微分脉冲伏安法(DPV),测定免疫夹心传感器的电化学性能。电流大小i_p(μA)与抗原的浓度在5～40 ng/mL成线性关系。线性回归方程为i_p(μA)=0.0305C(ng/mL)+0.0813,相关系数为0.9988,检出限为0.625 ng/m L(S/N=3)。     

基于3D打印技术构建石墨烯电化学生物传感器及其应用研究

超高灵敏度和特异性的电化学生物传感器在环境风险物质监测以及生物医学检测领域具有重要意义,而构建生物亲和性高、制备工艺简单、成本低廉的检查电极是电化学生物传感器走向应用的关键。本文采用3D打印技术制备出重复性良好的三维石墨烯复合电极,然后通过电化学氧化的方法调控表面石墨烯的形貌和氧化基团。所制备的电化学生物传感器在环境污染物微囊藻毒素(MC-LR)的检测中展现出超高的灵敏度,其线性检测区在4×10^-6~1 μg/L,检测限为1.5×10^-7 μg/L。同时,通过改变适配体检测探针后,该电化学生物传感器对于多巴胺、重金属Hg²⁺、四环素等均具有极高的检测灵敏度。本研究为电化学适配体生物传感器走向应用化提供了一种新的思路,为开发超高灵敏度环境监测和生物医学检测传感器提供一定的基础数据。     

PDMS微流控芯片-光纤传感器系统测定载脂蛋白apoB 100

以聚二甲基硅氧烷(PDMS)材料为研究对象,在微流控反应芯片内通过氧等离子体处理和聚乙烯亚胺-戊二醛交联法修饰PDMS微通道表面,实现了芯片内apoB 100的快速捕获和检测。设计了分立的集成了光纤传感器和"U"型PDMS微流控芯片的检测体系,根据催化反应前后颜色变化测定apoB 100浓度,消除了复杂的生物化学环境对光学检测的干扰。测试结果表明,由于微通道具有的较大的表面积/体积比,微流控免疫芯片把整个免疫反应及检测过程缩短至1h以内。该方法的检测限为1ng/mL,线性范围在1~20ng/mL。因此微流控免疫芯片-光纤传感器检测系统在临床应用和现场检测领域具有较大的发展潜力。     

基于铂、钯负载的MoS2纳米片构建生物传感器及应用

制备了Pt和Pd纳米颗粒修饰的单层MoS₂纳米片（Pt-Pd/MoS₂）,通过扫描电镜（SEM）、透射电镜（TEM）和X射线光电子能谱（XPS）对Pt-Pd/MoS₂外部形貌、内部结构和组成进行表征分析,并基于Pt-Pd/MoS₂修饰玻碳电极,并于表面固定乙酰胆碱酯酶（AChE）,制备AChE生物传感器。对比了Pt和Pd双金属纳米颗粒、商品化Pt/C及Pt-Pd/MoS₂的电化学性能,结果发现,Pt-Pd/MoS₂的电化学性能明显优于其他两种。测定电极表面酶催化反应的动力学参数K_m为883μmol/L;以马拉硫磷和甲基对硫磷为代表,考察制备电极的检测性能以及制备电极对有机磷农药的检测性能,马拉硫磷的检测范围是1×10^-14～1×10^-5mol/L,检测限为4.69×10^-14mol/L;甲基对硫磷的检测范围是1×10^-15～1×10^-5mol/L,检测限为5.23×10^-15mol/L（S/N=3）;并应用于真实样品检测OPs的回收率为91.4%～103%,显示出良好的回收率和准确性,可应用于实际样品的分析。Pt-Pd/MoS₂为二维纳米材料构建高效生物传感器提供了新思路。     

基于MnO2纳米片电化学传感器的制备及对水样H2O2的检测

构建MnO_2基纳米材料的高灵敏的H_2O_2电化学传感器;以MnSO_4·H_2O和KMnO_4为原料,采用水热反应法制备MnO_2纳米片,并用其修饰裸玻碳电极(GCE)构筑电化学传感器(MnO_2/GCE);该传感器对H_2O_2表现出极好地电化学响应特性,具有很强的抗干扰能力,H_2O_2测定的线性范围宽达0.05～3.82 mm,检测限低达9μm。该传感器成功地实现了对自来水和矿泉水样中H_2O_2的测定,表明该论文制备的MnO_2/GCE电极具有一定的实际应用价值。     

PDMS微流控芯片-光纤传感器系统测定载脂蛋白apoB 10

以聚二甲基硅氧烷(PDMS)材料为研究对象,在微流控反应芯片内通过氧等离子体处理和聚乙烯亚胺-戊二醛交联法修饰PDMS微通道表面,实现了芯片内apoB 100的快速捕获和检测。设计了分立的集成了光纤传感器和"U"型PDMS微流控芯片的检测体系,根据催化反应前后颜色变化测定apoB 100浓度,消除了复杂的生物化学环境对光学检测的干扰。测试结果表明,由于微通道具有的较大的表面积/体积比,微流控免疫芯片把整个免疫反应及检测过程缩短至1h以内。该方法的检测限为1ng/mL,线性范围在1~20ng/mL。因此微流控免疫芯片-光纤传感器检测系统在临床应用和现场检测领域具有较大的发展潜力。     

基于L-半胱氨酸/壳聚糖修饰的L-抗坏血酸电化学传感器的研究

通过将壳聚糖和L-半胱氨酸修饰到玻碳电极基底表面,制备了一种新型的电化学传感器,并将此传感器应用于对L-抗坏血酸的测定。通过循环伏安法和交流阻抗法对该传感器的电化学特性作了表征。通过线性伏安实验发现:L-抗坏血酸的氧化峰电流与其浓度在1.0×10-5~2.0×10-3mol/L范围内成良好的线性关系,检出限为4.3×10-6mol/L,且该传感器具有良好的重现性和稳定性,并将此传感器成功应用于对维生素C药片中L-抗坏血酸含量的检测。     

银纳米材料的制备及其电化学传感应用

通过化学还原法制备了银纳米粒子(AgNPs),结合多壁碳纳米管(MWCNTs),成功构置了AgNPs/MWCNTs/GCE电化学传感器,建立了测定亚硝酸盐的分析新方法。使用循环伏安法、安培法等电化学方法对其性能进行了检测。AgNPs/MWCNTs/GCE检测亚硝酸盐的线性范围为2.5×10-5～0.126 M,检出限为8.0×10-6M。该传感器具有构置简单方便,在测定亚硝酸盐时具有检出限低、线性范围宽、专一性高和重现性良好等优点。     

基于纳米铜-碳纳米纤维复合材料的电化学传感器检测芦丁

采用化学还原法制备了纳米铜-碳纳米纤维复合材料(CuNPs-CNFs),将其修饰在玻碳电极表面制备了一种检测芦丁的电化学传感器.在铁氰化钾-亚铁氰化钾体系中,采用电化学阻抗法和循环伏安法考察了传感器的电化学响应,研究了传感器的电化学性能;采用扫描电镜研究了传感器的表面形貌.在0.067 mol/L Na2 HPO4-N...     

微波消解－氢化物原子荧光光谱法同时测定化妆品中砷和汞

建立了一种简便、快速、高效的微波消解-氖化物原子荧光光谱法同时测定化妆品中砷和汞的厅法。重点探讨了样品前处理条件、仪器条件、载流溶液介质、预还原剂、还原剂等对试验测定结果的影响。在优化条件下,评价了方法的可靠性。元素砷在0-10ng/mL浓度范围内县有良好线性关系,线性相关系数（r）为0．9995．检出限为0．01ng／mL．加标回收率在97．6％～101．1％之间。元素汞存0～1ng／mL浓度范围内具有良好线性关系,线性相关系数（r）为0．9997．检出限为0．069ng／mL,加标回收率在93．7％～98．8％之间。将方法应用于化妆品中痕量砷和汞的分析,结果令人满意。     

聚亚甲基蓝/碳纳米管修饰电极阳极溶出伏安法测定痕量锡

研究了聚亚甲基蓝/碳纳米管修饰电极通过阳极溶出伏安法测定痕量Sn2+的电分析方法。Sn2+通过与电极表面的亚甲基蓝吩噻嗪环上S和N原子发生螯合作用而富集在电极表面,同时在-1.20 V(vs.SCE)还原成Sn0,当电极电势从-1.20 V向-0.30 V扫描时,被还原的Sn0从电极表面溶出。碳纳米管与亚甲基蓝的协同作用,使得Sn2+在该修饰电极上有良好的响应。Sn2+的溶出峰电流与其浓度在0.2×10-3~0.1 mmol/L浓度范围内呈良好的线性关系,检测限为0.1×10-3mmol/L。     

A highly selective electrochemical sensor for l‐tryptophan based on a screen‐printed carbon electrode modified with poly‐p‐phenylenediamine and CdS quantum dots

A new highly selective electrochemical sensor for the determination of l ‐tryptophan was proposed by modifying the surface of screen‐printed carbon electrodes (SPCEs). The surface of SPCE was firstly modified by electropolymerization of p‐phenylenediamine (PPD). The polymer film was then covalently linked with cysteamine capped cadmium sulfide quantum dots (Cys‐CdS QDs) by using glutaraldehyde (GA) as a cross‐linker resulted in an organic–inorganic hybrid composite film (QDs/GA/PPD/SPCE). The modified electrode was applied as a working electrode for detecting various amino acids. It was found that the modified electrode gave an electrochemical response selectively to l ‐tryptophan over other amino acids. The experimental parameters, including pH of solution, buffer types, electropolymerization cycles, scan rate, and accumulation time, were studied and optimized. The proposed sensor can be used to detect l ‐tryptophan with a low detection limit of 14.74 µmol L^?1 with good precision and the relative standard deviation less than 3.7%. The modified electrode was used to detect l ‐tryptophan in beverage samples and gave satisfactory recoveries from 91.9 to 104.9%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40356.     

Fabrication of an electrochemical immunosensor based on a gold–hydroxyapatite nanocomposite–chitosan film

A novel electrochemical immunosensor based on gold–hydroxyapatite nanocomposite–chitosan film has been developed for the detection of prostate-specific antigen. The large surface area of the gold–hydroxyapatite nanocomposite and the porous morphology of chitosan allowed high antibody loading without the loss of bioactivity. The stepwise modification of the electrode was characterized with cyclic voltammetry. Different parameters, including the pH of a supporting electrolyte, the size of the gold nanoparticles, and the antibody concentration were optimized. Under the optimal conditions, the electrochemical immunosensor reliably detected prostate-specific antigen at concentrations from 3.5 to 30 ng/mL with a detection threshold of 2.6 ng/mL. The prepared biosensor was used to assay prostate-specific antigen in human serum samples, and the results were in good agreement with those obtained by enzyme-linked immunosorbent assays. The reported immunosensor exhibits rapid detection, good reproducibility, high sensitivity, specificity, and stable performance. The proposed strategy can be extended for the development of other biosensors.     

Silica gel modified carbon paste electrode for electrochemical detection of insulin

A silica gel-modified carbon paste electrode (Si-CPE) was fabricated and used for selective and sensitive determination of insulin. The experimental results suggested that insulin effectively accumulated on surface of the modified electrode resulting in a marked enhancement of its oxidation current response. Therefore, the modified electrode was used as an electrochemical sensor for the differential pulse adsorptive stripping voltammetric and hydrodynamic amperometric determination of insulin. The influence of various experimental parameters on the voltammetric response of insulin was investigated. Using hydrodynamic amperometry, under optimum conditions, calibration plot for insulin was linear in the range of 90–1400 pM. The sensitivity and detection limit of the proposed amperometric method were found to be 107.3 pA/pM (1511.3 pA/pM cm²) and 36 pM, respectively. The electrode has the remarkable advantages of simple preparation using inexpensive material, high reproducibility, good chemical and mechanical stabilities, and easy surface renewal owing to bulk modification. The high selectivity of the modified electrode towards oxidation of insulin in the presence of sulfur containing amino acids including cystine, cysteine, and glutathione is a key advantage of the proposed electrode.     

Photoelectrocatalytic determination of NADH in a flow injection system with electropolymerized methylene blue

It was firstly described that a glassy carbon electrode electropolymerized with methylene blue shows an efficient photoelectrocatalytic activity towards NADH oxidation in a phosphate buffer solution (pH 7.0). In order to perform the photoelectrocatalytic determination of NADH in a flow injection analysis (FIA) system, a home-made flow electrochemical cell with a suitable transparent window for the irradiation of the electrode surface was constructed. The currents obtained from the photoamperometric measurements in the FIA system at optimum conditions (flow rate of carrier solution, 1.3 mL min⁻¹; transmission tubing length, 10 cm; injection volume, 100 μL; and constant applied potential, +150 mV vs. Ag/AgCl) were linearly dependent on the NADH concentration and linear calibration curves were obtained in the range of 1.0 × 10⁻⁷–2.0 × 10⁻⁴ M. The detection limit was found to be 4.0 × 10⁻⁸ M for photoamperometric determination of NADH.     

PVC membrane selective electrode for determination of cadmium(II) ion in chocolate samples

Benzil bis（carbohydrazone） （BBC） is prepared and explored as new NN Schiff’s base, which plays the role of an excellent ion carrier in the construction of a Cd（II） ion membrane sensor. The tris（2-ethylhexyl） phosphate best performance corresponds to a membrane composition of 30%poly （vinyl chloride）, 65%（TEHP）, 3.5%BBC and 1.5%tetradodecyl-ammoniumtetrakis（4-chlorophenyl） borate （ETH 500）. This sensor shows very good selectivity and sensitivity towards cadmium ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The effect of membrane composition, selectivity, pH and influence of additive on the response properties of electrode were investigated. The response mechanism was discussed in the view of UV-spectroscopy. The electrode exhibits a Nernstian behavior （with slope of 29.7 mV per decade） over a very wide concentration range from 1.0×10^-1 to 1.0×10^-8 mol·L^-1 with a detection limit of 3.2×10^-8 mol·L^-1. It shows rela-tively fast response time in whole concentration range （〈8 s） and can be used for at least 10 weeks in the pH range of 2.0-9.0. The proposed sensor is successfully used for the determination of cadmium in different chocolate sam-ples and as indicator electrode in titration with ethylene diamine tetraacetate （EDTA）.     

基于碳纳米管分子印迹聚合膜的西玛津电极研究

以除草剂西玛津(SMZ)为模板,在修饰有多壁碳纳米管(MWNTs)的玻碳电极表面通过电化学聚合邻氨基苯酚(oAP),制备了一种可对SMZ进行选择性测定的分子印迹聚合物膜电极。该印迹膜电极能在1.5~160μmol/L浓度范围内间接对SMZ进行检测,检出限为0.5μmol/L。并可在与SMZ结构相似的除草剂存在下选择性识别SMZ。     

乙二胺四乙酸二钠修饰碳糊电极测定铜(Ⅱ)

制备了乙二胺四乙酸二钠(EDTA)修饰碳糊电极并研究了铜在该电极上的阳极溶出伏安行为,提出了一种测定铜的新方法。实验发现,在pH=3.6的醋酸钠-醋酸缓冲溶液中,铜离子于-500 mV(vs.SCE)处被吸附还原,富集在该修饰电极表面。从-150 mV以120 mV/s的速率正向扫描至200 mV,铜在约90 mV处出现一灵敏的阳极溶出峰。峰电流与铜的浓度在1.0×10-8~2.0×10-6mol/L范围内呈良好的线性关系,检出限为1.0×10-9mol/L。并进行了回收率测试,回收率为93%~105%,相对标准偏差小于4%。