纳米金颗粒增强信号的表面等离子体共振生物传感器用于甲氧檗因高灵敏检测的研究

报道了一种基于表面等离子体共振(SPR)生物传感器的高灵敏检测抗癌药物甲氧檗因的新方法. 分别在纳米金颗粒和金膜表面修饰富含腺嘌呤(A)的DNA链, 当存在甲氧檗因时, 由于一个甲氧檗因分子可与4个A碱基相结合, 从而使得修饰在纳米金颗粒和金膜表面的DNA形成稳定的双链结构, 进而将功能化纳米金颗粒捕获在金膜表面. 由于纳米金颗粒与金膜之间的电场耦合效应可增强SPR信号, 从而可实现对小分子甲氧檗因的高灵敏、特异性检测. 本方法的检测下限低至0.07 pmol/L, 相对比色法和荧光法而言, 降低了约5～6个数量级. 以4种药物(盐酸小檗碱、青霉素G、硫酸庆大霉素、5-氟尿嘧啶)作为对照考察了该传感器的选择性, 结果表明该传感器具有较好的选择性.     

用于半胱氨酸检测的电化学生物传感器研究进展

半胱氨酸(Cys)作为人体重要的非必需氨基酸之一,对蛋白质合成、渗透调节、解毒过程、神经系统功能和抗氧化过程均发挥着重要作用,近年来广泛应用于医学临床、食品加工和生化研究领域。因此,发展快速、准确检测半胱氨酸浓度的方法具有重要意义。本文简要介绍了半胱氨酸的基本知识以及半胱氨酸的传统检测方法,对半胱氨酸定量检测的电化学传感器的研制与应用进行了重点阐述,并对其发展前景进行了展望。     

纳米颗粒复合材料增强的葡萄糖生物传感器

二氧化硅和金或铂组成的复合纳米颗粒可以大幅度地提高葡萄糖生物传感器的电流响应,其效果明显优于这三种纳米颗粒单独使用时对葡萄糖生物传感器的增强作用。除了具有吸附浓缩效应,吸附定向和量子尺寸颗粒 应外,复合纳米颗粒比单独一种纳米颗粒更易于形成连续势场,降低电子在电极和固定化酶间的迁移阻力,提高电子迁移率,有效地加速了酶的再生过程,因此复合纳米颗粒显著增强了传感器电流响应。     

纳米金、碳纳米管和纳米线及其在电化学生物传感器研究中的应用

综述了1995～2007年间,纳米金、碳纳米管和纳米线材料及其在电化学生物传感器研究中的新进展,引用文献60篇.     

纳米金在DNA生物传感器和基因芯片研究中的应用

综述了近年来纳米金在DNA生物传感器及基因芯片中的研究、应用和发展,并对其在生物科技方面的发展趋势进行了展望。参考文献31篇。     

基于金-铂纳米颗粒修饰的碳纳米管构建免标记电化学免疫传感器用于CEA检测

本文将金-铂双金属纳米颗粒(Au-PtNPs)沉积在羧基化的单壁碳纳米管表面作为基底材料,用以固载癌胚抗原抗体(anti-CEA)。利用anti-CEA与癌胚抗原(CEA)间的特异性识别作用将CEA固载于电极表面,用于降低Au-PtNPs对底物对苯二酚的催化作用,以改变电化学响应信号。通过对比CEA作用前后的电化学信号变化强弱可实现CEA的定量检测。研究发现,在最优实验条件下,CEA的浓度与电化学响应信号呈良好的线性关系。在0.05～80ng·mL~(-1)范围内其检测限为5 pg·mL~(-1)。该免疫传感器不仅展现出良好的选择性、重现性和稳定性,同时能成功用于人体血清样本的分析检测,其结果与酶联免疫方法(ELISA)检测结果相吻合。     

基于纳米金膜和稳定Y型结构的DNA电化学传感器

利用纳米金膜(GNF)和稳定的Y 型DNA 成功构建了一种具有良好选择性和较低检测限的DNA 传感器. 首先将金电极快速氧化后还原制成GNF, 利用Au-S 键将捕获探针DNA (c-DNA)有效地固定到GNF 电极表面, 在目标物存在的情况下, 将其与标记有亚甲蓝(MB)的指示探针(r-DNA)杂交形成Y 型结构. 利用GNF 独特的纳米性质和形成的Y型DNA 结构特点, 使MB 接近GNF, 从而提高了电子传递速率, 以差分脉冲伏安法(DPV)实现DNA 特定序列的检测,检测线性范围为1.0×10^-12～1.0×10^-9 mol/L, 检测下限为2.4×10^-13 mol/L. 与传统的传感器相比, 本方法提高了选择性, 减小了背景电流. 此外, 该传感器表现出良好的重现性和稳定性.     

基于金纳米颗粒信号放大效应电化学检测DNA聚合酶

基于金纳米颗粒(AuNPs)比表面积大、 尺寸小和能够承载大量DNA片段的特点, 建立了一种免标记、 简便、 快速检测DNA聚合酶Klenow fragment exo-(KF^-)的电化学方法. 首先将巯基化的DNA引物片段修饰在金电极上, 然后加入模板DNA链以及修饰有报告DNA链的金纳米颗粒(AuNPs-DNA), 模板DNA链能同时与DNA引物片段和修饰在AuNPs上的报告DNA链进行互补杂交形成"三明治"结构, 从而将AuNPs-DNA修饰在电极表面; 当加入电活性物质钌铵(RuHex)后, RuHex可通过静电吸附作用结合在DNA上. AuNPs上修饰的报告DNA链能够吸附大量RuHex, 导致电化学信号放大. 当加入脱氧核糖核苷三磷酸(dNTPs)以及KF^-聚合酶后, 引物片段发生延伸反应, 将与模板DNA链杂交的AuNPs-DNA竞争下来, 带走大量的RuHex, 使电信号降低, 从而实现对聚合酶的检测. 实验结果表明, 利用该方法可以检测到5 U/mL的KF^-.     

纳米粒子在电化学DNA生物传感器研究中的应用

简要介绍了电化学DNA生物传感器的原理和分类,对纳米粒子在电化学DNA生物传感器研究中的应用进行了详细评述.     

金纳米颗粒可视化传感器在生物分子分析中的研究进展

基于金纳米颗粒的可视化传感器具有灵敏度高、选择性好、肉眼可见、无需大型仪器等优点,是一种具有应用潜力的分析检测方法。生物分子分析检测与人体健康息息相关。本文综述了近几年基于金纳米颗粒的可视化传感器在生物分子分析中的应用研究。     

纳米金胶增强葡萄糖生物传感器的构建

将纳米金胶(AuNPs)和羟基磷灰石(HAp)按一定比例混合制备了新型复合膜用于葡萄糖氧化酶(GOD)的固定,构建了高灵敏的葡萄糖传感器。由于纳米金胶的存在,葡萄糖氧化酶的直接电化学性质得以增强,在去除氧气的PBS(pH 7.0)介质中,固定在复合膜内的GOD表现出一对良好的氧化还原峰。在饱和氧气条件下,当加入一定量的葡萄糖时,由于GOD催化葡萄糖氧化消耗溶液中的溶解氧,-0.8 V处溶解氧的还原峰电流降低,且峰电流降低的量与葡萄糖浓度在0.02～1.62 mmol/L范围内呈线性相关,检出限为5.0μmol/L,检测灵敏度达9.91 mA.mol-1.L,可实现对葡萄糖的快速检测。     

Biosensor for multiplex detection of two DNA target sequences using enzyme-functionalized Au nanoparticles as signal amplification

Multiplex electrochemical detection of two DNA target sequences in one sample using enzyme-functionalized Au nanoparticles (AuNPs) as catalytic labels for was proposed. This DNA sensor was fabricated using a “sandwich” detection strategy, involving two kinds of capture probes DNA immobilized on glassy carbon electrode (GCE), and hybridization with target DNA sequences, which further hybridized with the reporter DNA loaded on the AuNPs. The AuNP contained two kinds of DNA sequences, one was complementary to the target DNA, while the other was noncomplementary to the target. The noncomplementary sequences were linked with horseradish peroxidase (HRP) and alkaline phosphatase (ALP), respectively. Enhanced detection sensitivity was obtained where the AuNPs carriers increased the amount of enzyme molecules per hybridization. Electrochemical signals were generated from the enzymatic products produced from the substrates catalyzed by HRP and ALP. Under optimal conditions, a 33-mer sequence could be quantified over the ranges from 1.5 × 10⁻¹³ to 5.0 × 10⁻¹² M with a detection limit of 1.0 × 10⁻¹³ M using HRP-AuNP as labels, and a 33-mer sequence could be quantified over the ranges from 4.5 × 10⁻¹¹ M to 1.0 × 10⁻⁹ M with a detection limit of 1.2 × 10⁻¹¹ M using ALP-AuNP as labels.     

A Sensitive Nanoporous Gold-Based Electrochemical DNA Biosensor for Escherichia coli Detection

A sensitive electrochemical DNA biosensor based on a mixed monolayer structure self-assembled at nanoporous gold (NPG) electrode surface was prepared for Escherichia coli (E. coli) detection. The NPG was fabricated on gold electrode, onto which thiolated oligonucleotides (SH-DNA) and mercaptohexanol (MCH) were covalently linked forming a mixed self-assembled monolayer (SAM). The hybridization between the SH-DNA/MCH modified biosensor and E. coli DNA was monitored with differential pulse voltammetry measurement using methylene blue (MB) as the hybridization indicator. The biosensor can detect 1 × 10^?12 M DNA target and 50 cfu/μL E. coli without any nucleic acid amplification steps. The detection limit was lowered to 50 cfu/mL after 5.0 h of incubation.     

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。     

Electrochemical DNA nano-biosensor for the detection of genotoxins in water samples简

In the present study, a disposable electrochemical DNA nano-biosensor is proposed for the rapid detection of genotoxic compounds and bio-analysis of water pollution. The DNA nano-biosensor is prepared by immobilizing DNA on Au nanoparticles and a self-assembled monolayer of cysteamine modified Au electrode. The assembly processes of cysteamine, Au nanoparticles and DNA were characterized by cyclic voltammetry （CV）. The Au nanoparticles enhanced DNA immobilization resulting in an increased guanine signal. The interaction of the analyte with the immobilized DNA was measured through the variation of the electrochemical signal of guanine by square wave voltammetry （SWV）. The biosensor was able to detect the known genotoxic compounds： 2-anthramine, acridine orange and 2- naphthylamine with detection limits of 2, 3 and 50 nmol/L, respectively. The biosensor was also used to test actual water samples to evaluate the contamination level. Additionally, the comparison of results from the classical genotoxiciw bioassay has confirmed the applicability of the method for real samoles.     

A No-washing Point-of-Care Electrochemical Biosensor Based on CuS Nanoparticles for Rapid and Sensitive Detection of Neuron-specific Enolase

Electrochemical biosensors have made outstanding achievements in recent years. However, the single pursuit of sensitivity and accuracy sometimes cannot meet the detection requirements and achieve high-efficiency measurements. Therefore, no-washing biosensors have more practical advantages. In this work, a disposable point-of-care (POC) electrochemical biosensor was designed for the sensitive and fast detection of neuron-specific enolase (NSE). Fe₃O₄ and CuS nanoparticles were used as the substrate material for capturing Ab₁ and the signal probe for labeling Ab₂ respectively. The disposable syringe filter was introduced into the determination procedure for simple sample separation, which easily realized no-washing detection. Due to the syringe filters with 200 nm pore diameter could only allow the small nanoparticles of CuS−Ab₂ pass through, the large-sized immunocomplex of Fe₃O₄−Ab₁/NSE/CuS−Ab₂ were blocked on the membrane. The uncombined CuS−Ab₂ particles were pushed out from the syringe and would occur electron transfer between Cu²⁺ and Cu⁺ to generate a current signal detected by the Au electrode. Under optimal conditions, the no-washing biosensor shows a wide linear concentration range (100 fg mL⁻¹∼50 ng mL⁻¹) with the limit of detection of 33 fg mL⁻¹ (S/N=3). Additionally, the biosensor exhibited excellent selectivity, storage stability and reproducibility. The outstanding advantages of the no-washing biosensor make it more suitable for POC testing.     

Design and Development of a Non-Enzymatic Electrochemical Biosensor for the Detection of Glutathione

Glutathione (GSH-reduced form) is a tripeptide that plays a vital role as an antioxidant to remove xenobiotics in the human body and changes in GSH levels are a marker for the progression of various diseases. In this context, a highly sensitive non-enzymatic electrochemical biosensor for the detection of GSH has been developed using reduced graphene oxide Manganese oxide (rGMnO) nanocomposite as the nano-interface. Initially, graphene oxide was synthesized by Hummer's method and then thermally reduced in the presence of MnO₂ in a blast furnace to obtain rGMnO nanocomposite. The nanocomposite was characterized to validate its structure and morphological properties via Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry and amperometry studies showed that upon the addition of GSH, the Pt/rGMnO modified working electrode exhibited a linear response in the range of 1–100 μM at an input voltage of −0.62 V. The developed sensor was found to have a sensitivity of 0.3256 μA μM⁻¹ and LOD of 970 nM with a recovery of 92–104 % in real blood serum samples.     

Amperometric Glucose Biosensor Based on Electrochemically Deposited Gold Nanoparticles Covered by Polypyrrole

Graphite rod (GR) modified with electrochemicaly deposited gold nanoparticles (AuNPs) and adsorbed glucose oxidase (GOx) was used in amperometric glucose biosensor design. Enzymatic formation of polypyrrole (Ppy) on the surface of GOx/AuNPs/GR electrode was applied in order to improve analytical characteristics and stability of developed biosensor. The linear glucose detection range for Ppy/GOx/AuNPs/GR electrode was dependent on the duration of Ppy‐layer formation and the linear interval was extended up to 19.9 mmol L⁻¹ after 21 h lasting synthesis of Ppy. The sensitivity of the developed biosensor was determined as 21.7 μA mM⁻¹ cm⁻², the limit of detection – 0.20 mmol L⁻¹. Ppy/GOx/AuNPs/GR electrodes demonstrated advanced good stability (the t _1/2 was 9.8 days), quick detection of glucose (within 5 s) in the wide linear interval. Additionally, formed Ppy layer decreased the influence of electroactive species on the analytical signal. Developed biosensor is suitable for the determination of glucose in human serum samples.     

基于铂纳米颗粒电沉积镁铝水滑石修饰电极的电化学葡萄糖生物传感器

采用成核/晶化隔离法合成了镁铝水滑石纳米颗粒,将其修饰到氧化铟锡导电玻璃电极表面;在此修饰电极基础上,利用电沉积还原氯铂酸盐法制备了铂纳米颗粒/水滑石复合修饰电极.由于水滑石层板表面的外限域作用有效抑制了铂纳米颗粒的聚集,使该电极对过氧化氢具有较好的电催化性能.基于镁铝水滑石良好的生物相容性,将葡萄糖氧化酶进一步修饰到该电极表面,实现了对葡萄糖高灵敏的电化学检测,检出限(S/N=3)达1.0μmol/L.