非标记型双底物检测核酸适配体传感器研究

采用电沉积法制备了铁氰化镍(NiHCF)氧化还原电化学探针, 以金纳米粒子(GNPs)为固定核酸适配体的载体构建了非标记型测定凝血酶(TB)和腺苷(AD)的核酸适配体传感器. 采用循环伏安法(CV)和SEM对NiHCF膜进行了表征; 利用电化学阻抗(EIS)对传感器的组装过程进行了监测; 用CV和差分脉冲伏安法(DPV)对该传感器的电化学行为进行了研究. 该传感器对凝血酶的检测在1.0 fg·mL^-1～1.0 μg·mL^-1范围内成良好的线性关系, 相关系数为0.997, 检测限为0.27 fg·mL^-1; 对腺苷的检测在1.0 fg·mL^-1～1.0 ng·mL^-1范围内成良好的线性关系, 相关系数为0.997, 检测限为0.36 fg/mL. 该传感器制备简单, 灵敏度高, 抗干扰能力强.     

以聚硫堇为电化学探针的非标记型核酸适配体传感器

采用电聚合法制备了聚硫堇氧化还原电化学探针, 以金纳米粒子为固定核酸适配体的载体构建了非标记型核酸适配体传感器. 用电化学阻抗谱对传感器的组装过程进行了监测, 用循环伏安法和差分脉冲伏安法考察了传感器的电化学行为. 结果表明, 该传感器对凝血酶的检测在1.0 pg/mL～500 ng/mL范围内呈良好的线性关系, 相关系数为0.998, 检出限为0.38 pg/mL. 该传感器制备简单、 灵敏度高且抗干扰能力强.     

半胱氨酸封闭剂为电化学探针的非标记型核酸适配体传感器

采用半胱氨酸为封闭剂和氧化还原电化学探针,制备了一种新型的非标记型电化学核酸适配体传感器,并用于测定凝血酶。 利用电化学阻抗对传感器的组装过程进行了监测。 用循环伏安法和差分脉冲伏安法研究了该传感器的电化学行为。 探讨了凝血酶孵育时间、测试pH值对传感器响应的影响。 该传感器对凝血酶在10.0~10000 μg/L范围内呈良好的线性响应,检测限为2.47 μg/L。     

基于水滑石-金纳米粒子的阻抗型核酸适配体传感器的研究

在玻碳电极表面用电化学沉积法一步合成钴铝水滑石-金纳米粒子(CoAl LDH-GNPs)复合纳米材料,以复合纳米材料作为核酸适配体(Apt)的固定化基质,建立了一种高灵敏的阻抗型适配体传感器.采用扫描电镜(SEM)和能量色散谱仪(EDS)对CoAl LDH-GNPs复合纳米材料进行了表征,对电极的组装过程采用循环伏安法和电化学阻抗进行表征,对传感器的性能采用电化学阻抗进行研究.复合纳米材料CoAl LDH-GNPs构筑的传感器对凝血酶(THR)具有良好的信号响应,线性相关系数R=0.995,检出限为0.3 ng/L(S/N=3),检测范围为1.0 ng/L～ 100 μg/L.     

基于铁氰化铜的非标记型核酸适配体传感器的构建及其对腺苷的检测

采用电化学沉积法在金电极表面制备了铁氰化铜(CuHCF)氧化还原电化学探针,通过CN~-(CuHCF)和金纳米粒子(GNPs)之间形成Au-CN键的强相互作用力,将GNPs组装到电极表面后,再通过Au-S键将巯基化的腺苷适配体组装到电极表面,构建了高灵敏检测腺苷的非标记型核酸适配体传感器。利用电化学阻抗对传感器的组装构建过程进行监测。用循环伏安法和差分脉冲法考察了该传感器的电化学行为,并探讨了支持电解质和扫速对传感器的影响。在最优实验条件下,该传感器对腺苷在100 fg/mL~50.0 ng/mL范围内呈良好的线性响应,相关系数为0.998,检出限为45.0 fg/mL。     

石墨烯修饰电化学适配体传感器测定双酚A

构建了一种检测双酚A(BPA)的电化学适配体传感器。利用在线电化学方法将氧化石墨烯还原为石墨烯,通过石墨烯与单链DNA之间的相互作用,将BPA适配体单链DNA吸附固定在修饰电极上,制备了BPA电化学适配体传感器。以铁氰化钾-亚铁氰化钾平衡电对为电化学探针,利用电化学循环伏安法和差分脉冲伏安法对BPA传感器的性能进行了研究。结果表明,在最优化实验条件下,传感器对BPA的检测线性范围在1.0×10~(-15)~1.0×10~(-10)mol/L之间,检出限为3.3×10~(-16)mol/L(S/N=3)。     

基于主客体竞争模式的凝血酶适配体传感器的研究

基于β-环糊精(β-CD)主客体竞争模式,构建了开关型凝血酶适配体电化学传感器.将末端修饰了二茂铁(Fc)的核酸适配体通过与β-CD的主客体识别固定在金电极表面,当凝血酶存在时,适配体由原来的直立线状构型变为"G-四链体",远离电极表面,适配体探针的氧化还原电流强度减小,即"Signal-off".利用此效应对凝血酶进行了灵敏检测,结果表明,在5.0×10-13~5.0×10-9 mol/L浓度范围内,凝血酶的浓度与电化学响应信号呈良好的线性关系,检出限为2.0×10-13 mol/L(3σ).与其它蛋白分子相比,本方法对凝血酶蛋白的检测具有高特异性.本传感器构建简单,再生性好,为生物血清样本中凝血酶的实时高效检测提供了方法.     

基于纳米铁氰化镍修饰二氧化钛纳米管阵列电极的非酶葡萄糖传感器

以二氧化钛纳米管阵列(TNTs)为基底,利用脉冲电沉积的方法将Ni纳米粒子沉积在TNTs管内,通过循环伏安法将Ni转化为铁氰化镍(NiHCF),构造了新型的非酶型葡萄糖生物传感器(NiHCF/TNTs修饰电极)。在优化的实验条件下,传感电极的灵敏度为663μA/(mmol cm2);响应电流与葡萄糖浓度在1～23mmol/L范围内呈现良好的线性关系。在低浓度检测下,线性范围为2×10-3～1.0 mmol/L;检出限为0.5μmol/L。本传感电极具有灵敏度高、稳定性好和抗干扰能力强等特点。     

聚硫堇为探针与固定化载体的适配体传感器用于双酚A的检测研究

研制了一种简单和灵敏地检测环境激素双酚A(BPA)的电化学适配体传感器。首先在玻碳电极(GCE)表面采用电沉积法沉积一层多孔纳米金(NP-Au),再采用电聚合法将硫堇(TH)和适配体(APT)一步聚合到电极表面,以聚硫堇(PTH)作为电化学探针和APT的固定化载体,以牛血清白蛋白(BSA)抑制非特异性吸附,构筑GCE/NP-Au/PTH+APT/BSA传感器。采用差分脉冲伏安法对该传感器的电化学性能进行探究,发现双酚A在10.0 fg/mL~1.0 ng/mL浓度范围内有较好的信号响应,检出限为5.3 fg/mL。以GCE/PTH+APT/BSA传感器作为对照,其对双酚A在10.0 fg/mL~1.0 ng/mL浓度范围内呈线性关系,检出限为9.0 fg/mL。结果表明多孔纳米金的引入可有效提高传感器的灵敏度。GCE/NP-Au/PTH+APT/BSA传感器具有选择性高和检出限低等优点。     

导电高分子纳米粒子负载探针的凝血酶电化学发光适配体传感器

以特异性识别凝血酶的适配体为分子识别物质,以氨基钌联吡啶衍生物（Ru1）为电化学发光信号物质,基于吡咯/N-（2-羧乙基）吡咯纳米粒子（Ppy-pa NPs）负载适配体和Ru1研制了一种高灵敏检测凝血酶的电化学发光适配体传感器.以N-（2-羧乙基）吡咯和吡咯为单体,采用微乳液聚合方法制备了Ppy-pa NPs.通过EDC/NHS将Ru1与Ppy-pa NPs表面的羧基共价连接制备了Ru1功能化Ppy-pa NPs（Ru1-Ppy-pa NPs）.利用核磁共振图谱、傅里叶变换红外光谱和投射电子显微镜图对Ppy-pa NPs和Ru1-Ppy-pa NPs进行了表征.将Ppy-pa NPs Nafion混合物滴涂在石墨电极表面制备成电化学发光化学传感器,可高灵敏检测三丙胺（检出限为3.0×10-8M）.通过电化学氧化将对氨基苯磺酸共价键合在石墨电极表面,将5′修饰氨基凝血酶适配体I（TBA-I）共价连接在对氨基苯磺酸修饰的石墨电极表面制备成电化学发光适配体传感器.将5′修饰氨基凝血酶适配体Ⅱ（TBA-Ⅱ）标记在Ru1-Ppy-pa NPs表面制得电化学发光适配体信号探针（Ppy-pa NPs-Ru1-TBA-II）.当凝血酶存在时,凝血酶与电极表面的TBA-I特异性结合,再与信号探针结合形成夹心结构,产生很强的电化学发光信号.该传感器具有极低的检出限（3.0×10-16M）和良好的选择性.本工作表明以Ppy-pa NPs为电化学光探针的载体可构建高灵敏度和选择性的电化学发光生物传感器.     

聚赖氨酸/多壁碳纳米管修饰电极测定大米中的铅

通过滴涂及电聚合方式分别将多壁碳纳米管和赖氨酸共修饰于玻碳电极上,制备出聚赖氨酸/多壁碳纳米管修饰电极,并建立了阳极溶出伏安法测定铅离子的新方法。采用线性扫描伏安法及循环伏安法研究了铅离子在修饰电极上的电化学行为,并考察了测定底液、底液p H值、富集电位、富集时间等条件的影响。在最佳实验条件下,铅离子的溶出峰电流与其浓度在2.0×10-7~8.0×10-5mol·L-1范围内呈良好的线性关系,检出限为1.0×10-7mol·L-1。利用所制备的修饰电极对大米样品进行加标回收实验,回收率为98%~102%。该方法具有良好的灵敏度和稳定性,已成功应用于大米样品中铅离子的测定。     

A uric acid sensor based on electrodeposition of nickel hexacyanoferrate nanoparticles on an electrode modified with multi-walled carbon nanotubes

An electrode sensitive to uric acid was prepared by electrodeposition of nickel(II) hexacyanoferrate(III) on the surface of a glassy carbon electrode modified with multi-walled carbon nanotubes. The morphology of the material was characterized by scanning electron microscopy and Fourier transform infrared spectrometry. The modified electrode were characterized via cyclic voltammetry and amperometry (i - t). It exhibited efficient electron transfer ability and a strong and fast (< 3?s) response towards uric acid which is linear in the range from 0.1???M to 18???M, with a lower detection limit of 50 nM (at an S/N ratio of 3). In addition, the electrode exhibited good reproducibility and long-term stability.

Electrochemical synthesis of gold nanoparticles on the surface of multi-walled carbon nanotubes with glassy carbon electrode and their application

Gold nanoparticles on the surface of multi-walled carbon nanotubes with glassy carbon electrode were prepared using electrochemical synthesis method. The thin films of gold Nanoparticles/multi-walled carbon nanotubes were characterized by scanning electron microscopy, powder X-ray diffraction, and cyclic voltammetry. Electrochemical behavior of adrenaline hydrochloride at gold nanoparticles/multi-walled carbon nanotube modified glassy carbon electrode was investigated. A simple, sensitive, and inexpensive method for determination of adrenaline hydrochloride was proposed.     

Electrochemical DNA biosensors based on platinum nanoparticles combined carbon nanotubes

Platinum nanoparticles were used in combination with multi-walled carbon nanotubes (MWCNTs) for fabricating sensitivity-enhanced electrochemical DNA biosensor. Multi-walled carbon nanotubes and platinum nanoparticles were dispersed in Nafion, which were used to fabricate the modification of the glassy carbon electrode (GCE) surface. Oligonucleotides with amino groups at the 5′ end were covalently linked onto carboxylic groups of MWCNTs on the electrode. The hybridization events were monitored by differential pulse voltammetry (DPV) measurement of the intercalated daunomycin. Due to the ability of carbon nanotubes to promote electron-transfer reactions, the high catalytic activities of platinum nanoparticles for chemical reactions, the sensitivity of presented electrochemical DNA biosensors was remarkably improved. The detection limit of the method for target DNA was 1.0 × 10⁻¹¹ mol l⁻¹.     

Portable Electrochemical Sensing of Indole-3-acetic Acid Based on Self-assembled MXene and Multi-walled Carbon Nanotubes Composite Modified Screen-printed Electrode

As a typical plant hormone, indole-3-acetic acid (IAA) can regulate the biological activities including division, growth and differentiation of plant cells. In this paper, a MXene and multi-walled carbon nanotubes composite was prepared by self-assembly procedure, which was modified on screen-printed electrode (SPE) to construct a wireless portable electrochemical sensor. Electrochemical investigations of IAA were studied by cyclic voltammetry and an irreversible oxidation process could be observed. The excellent electroanalytical method of IAA was realized on the modified SPE with the detection range as 0.05–125.0 μmol/L and the detection limit as 16.7 nmol/L. The sensor was used for IAA content analysis in different part of pea seedlings with satisfactory results.     

POMs as Active Center for Sensitively Electrochemical Detection of Bisphenol A and Acetaminophen

A new type of electrochemical sensor based on multi-walled carbon nanotubes(MWCNTs), K2H4SiW11CuO39-6H2O(SiW11Cu) and gold nanoparticles(AuNPs) was prepared for the simultaneous detection of bisphenol A and acetaminophen. Differential pulse voltammetry(DPV), cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were used for electrochemical characterization, and Fourier transfonn infrared spectroscopy(FTIR) was used to characterize the structure of polyoxometalates. Electrochemical experimental results show that the composite modified electrodes have good electrochemical activity as well as current response values of bisphenol A and acetaminophen when pH=7.0. At the same time, the modified electrode exhibits good stability and reproduction, and has good anti-interference ability to other substances. In practical application, the sensor obtained satisfactory results.     

基于Ru(bpy)2+3/AuNPs/SWCNTs/腺苷适配体电化学发光生物传感器用于腺苷的检测

利用AuNPs/Nafion复合膜技术固定Ru(bpy)2+3,采用羧基化碳纳米管固定氨基化腺苷适配体,制备腺甘电化学发光生物传感器.采用循环伏安法和电化学发光法对传感器进行表征.结果表明,此传感器具有良好的稳定性和重现性.腺苷与传感器作用后,腺苷与其适配体形成G四面体结构,Ru(bpy)2+3的电化学发光强度降低.在最佳实验条件下,电化学发光强度降低量与腺苷浓度的负对数在1.0×10-11~1.0×10-7 mol/L范围内呈良好的线性关系,线性方程为ΔIECL=-890lgC-5050,检出限(S/N=3)为5.0 × 10-12 mol/L.对1.0 × 10-10 mol/L腺苷平行测定11次,相对标准偏差为2.7%.用于尿液中腺苷的测定,加标回收率在 97.1%~110.0%之间.