纳米金增强DNA修饰金电极电化学性能

纳米金自组装于金电极表面可以增强DNA在电极表面的固着量.用恒电位吸附的方式将小牛胸腺DNA修饰到金电极上,并通过Co(bpy)33+表征修饰电极的电化学性能.比较了在纳米金修饰金电极上吸附的DNA数量与在裸金电极上吸附DNA的数量,前者有明显的增大,并考察了DNA修饰金电极的稳定性.探讨了ssDNA与dsDNA的吸附特性,同时,比较了DNA在不同电极基体上的吸附行为特性.     

电聚合二氧化锆固载辣根过氧化物酶的第三代生物传感器的研制

利用生物相容性良好的无机材料二氧化锆(ZrO2)对辣根过氧化物酶(HRP)进行直接固定,用交流阻抗法对修饰电极进行了表征,并用循环伏安法和计时电流法对过氧化氢(H2O2)生物传感器的性能进行了研究.结果表明,该法成功的制备了以电聚合ZrO2为载体的无介体第三代电流型生物传感器.其线性范围为1.00×10-6～1.87×10-3mol/L,线性回归方程为:ip(μA)=0.002 3 c(μmol/L)+2.9324,相关系数r为0.996 8,检测限为2.86×10-7 mol/L.     

基于纳米金修饰丝网印刷电极的乙醇生物传感器

在丝网印刷电极上利用吸附法固定乙醇脱氢酶,并用纳米金进行修饰,以铁氰化钾为介体制作了用于酒精检测的一次性乙醇脱氢酶电极试纸.纳米金颗粒修饰酶电极,极大地改善了电极电流响应,提高了传感器的灵敏度.此乙醇传感器的响应时间仅为25 s,灵敏度为0.06 μA(mmol/L)~(-1),线性浓度测量范围为1.0 mmol/L至10 mmol/L.     

壳聚糖修饰的过氧化氢生物传感器的研究

用壳聚糖固定辣根过氧化物酶(HRP),采用硫堇作为电子媒介,戊二醛作为交联剂,制备了HRP/壳聚糖/硫堇/GC电极.讨论了硫堇的固定方法,考察了该传感器在优化的实验条件下对H2O2的响应特性,实验结果表明,该传感器对H2O2表现出良好的响应特性,如响应快、稳定性好和抗干扰性能强等优点,检测范围为5.0 ×10-6～3.0×10-3mol/L.检出限为1.0×10-6mol/L.电极在用于实际试样回收率的测定中,结果良好.     

基于二氧化锆纳米粒子固定乙酰胆碱酯酶的甲基对硫磷传感器

先在金电极表面电沉积二氧化锆纳米粒子并固定乙酰胆碱酯酶(AChE),将此电极浸入含有不同浓度的有机磷溶液中,根据电极在底物氯化乙酰巯基胆碱中电化学信号强度的大小来实现溶液中有机磷的定量检测.以甲基对硫磷为分析目标物,研究了传感器的主要响应特性、选择性及再生性能,考察了底物浓度、工作电位及溶液pH值对分析性能的影响.结果表明,该有机磷传感器在5.0×10-7～5.0×10-4 g/L浓度范围内对目标分析物有线性响应,检出限为1.0×10-7 g/L.该传感器灵敏度高,非特异性吸附小,再生性好,所用的二氧化锆纳米粒子层制备简单、操作方便,具有较大的应用潜力.     

基于半胱氨酸／PDDA／纳米金共修饰的过氧化氢生物传感器研究

将L-半胱氨酸、聚二烯丙基二甲基氯化铵(PDDA)、纳米金及血红蛋白(Hb)自组装到金电极表面,制成了新型过氧化氢生物传感器.采用循环伏安法和计时电流法对该传感器的性能进行了详细研究.实验发现,该传感器增加了酶的吸附量,响应快、稳定性好,对H2O2表现出良好的响应特性.检测范围为4.2×10-7～3.0×10-3 mol/L,检出限为1.4×10-7 mol/L,并具有抗尿酸、抗坏血酸等干扰的特点.     

碳纳米管-铂纳米颗粒修饰金电极用于葡萄糖生物传感器的研究

用交联剂戊二醛把葡萄糖氧化酶(GOx)固定在多聚赖氨酸(polylysine)修饰的碳纳米管(CNT)上,然后将Nafion和修饰上葡萄糖氧化酶的碳纳米管(CNT-lysine-GOx)混合均匀涂在Pt纳米颗粒修饰的金电极表面制备成葡萄糖传感器。探讨了Pt沉积时间、Nafion中碳纳米管的含量、缓冲液的pH值以及工作电位对电极响应的影响。实验结果表明该传感器具有响应快、稳定性好等优点,催化电流与葡萄糖的浓度在0.1μmol/L～6mmol/L范围内成线性关系,响应时间小于5s。     

基于壳聚糖-纳米TiO2复合膜／CdSe固定血红蛋白的过氧化氢生物传感器的研究

以壳聚糖/nano-TiO2复合膜为基底固载量子点硒化镉(CdSe)和血红蛋白(Hb)制备过氧化氢生物传感器.用循环伏安法对修饰电极进行了表征,并用计时电流法对过氧化氢(H2O2)生物传感器的性能进行了研究.结果表明,在优化的实验条件下,该传感器的响应电流与其浓度在3.9×10-6～1.2×10-2mol/L范围内呈良好的线性关系,检出限为1.0×10-6mol/L.该传感器的米氏常数为1.65mmol/L,表明所固定的酶具有较高的生物活性.     

电化学沉积二氧化锆制备DNA电化学传感器

设计了一种简单、方便的电化学DNA生物传感器的制作方法,首先在硼掺杂的金刚石电极(BDD)表面电化学沉积一层二氧化锆薄膜,利用二氧化锆的分子结构特点,将探针DNA即5’末端修饰磷酸基团的寡核苷酸短链(ssDNA)连接到二氧化锆薄膜上.以亚甲基蓝(MB)为氧化还原的电子媒介体,应用循环伏安法和差分脉冲法测试了该电极的性能...     

基于氧化石墨烯修饰的DNA生物传感器用于苯酚的检测

作为一种典型的优先控制污染物,苯酚一直是环境监测和污染控制的重要对象。基于氧化石墨烯大的比表面积、优良的电子传导性等特性,以其为桥梁,为DNA在玻碳电极上的固定提供了可能,并加大了DNA在电极上的电化学响应信号,由此而构建了一种性能优良的DNA生物传感器。将该传感器浸在含有苯酚的溶液中,由于苯酚对DNA的损伤作用,降低了DNA在电极上的电化学响应。实验发现,响应信号与苯酚的浓度对数呈现良好的线性关系,响应范围为1.0×10-8～1.0×10-4mol/L,此外,该生物传感器表现出良好的稳定性和重现性。     

Immobilization of horseradish peroxidase and nile blue into the ormosil nanocomposite for the fabrication of hydrogen peroxide biosensor based on MWCNT modified glassy carbon electrode

A novel approach to construct a second-generation amperometric biosensor is described. The classical redox dye nile blue (NB) as mediator and horseradish peroxidase as a base enzyme were coimmobilized into the multiwalled carbon nanotubes (MWCNTs) modified ormosil matrix. Nafion was dispersed into the matrix to enhance the rate of the electron transfer and prevent the cracking of the ormosil film. The surface morphology of MWCNT/NB/NAF/HRP nanocomposite was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). Cyclic voltammetry and amperometry measurements were used to study and optimize the performance of the resulting peroxide biosensor. The apparent Michaelis–Menten constant was determined to be 1.1 mM. The effect of pH, applied potential and amount of the HRP enzyme on the electrochemical biosensor has been systematically studied. The fabricated biosensor demonstrated significant electrocatalytic activity for the reduction of hydrogen peroxide with wide linear range from 2 × 10⁻⁷ to 3.8 × 10⁻⁴ M, and low detection limit 1 × 10⁻⁷ M (S/N = 3) with fast response time <3 s. The facile procedure of immobilizing HRP and MWCNTs into the ormosil used in the present work can promote the development of electrochemical research for enzymes, proteins, biosensors, biofuel cells and other bioelectrochemical devices.     

Hemin functionalized graphene nanosheets-based dual biosensor platforms for hydrogen peroxide and glucose

In this paper, we present dual biosensor platforms based on hemin functionalized graphene nanosheets (H-GNs). The nanomaterial combines the features of both graphene (high conductivity and surface area) and hemin (excellent catalysis and intrinsic peroxidase-like activity). It not only shows excellent electrocatalysis of the reduction of H₂O₂ but also exhibits intrinsic peroxidase-like activity that can catalyze H₂O₂ to oxidize 3,3,5,5-tetramethylbenzidine (TMB) to produce a blue color reaction. Based on these properties, the simple, economical, and highly sensitive amperometric and colorimetric biosensors for H₂O₂ and glucose have been developed. The linear relationships for H₂O₂ and glucose were obtained from 0.5 μM to 0.4 mM and 0.05 μM to 0.5 mM by amperometric and colorimetric methods, respectively. The detection limits for H₂O₂ and glucose reached to 0.2 μM and 0.3 μM by amperometric method. By colorimetric methods, the detection limits for H₂O₂ and glucose were as low as 20 nM and 30 nM, respectively. The rapid, simple and sensitive sensing platform showed great promising applications in the pharmaceutical, clinical and industrial detection of H₂O₂ and glucose.     

A novel electrochemiluminescence glucose biosensor based on alcohol-free mesoporous molecular sieve silica modified electrode

In this study, a thin-film glucose electrochemiluminescence (ECL) biosensor was developed. Ru(bpy)₃²⁺ was doped in alcohol-free low-volume shrinkage mesoporous silica sol-gel with PEG-400 as the template, and glucose dehydrogenase (GDH) was immobilized in polymer Resydrol. NADH, which is produced by the reaction of co-enzyme NAD⁺ and glucose catalyzed by glucose dehydrogenase, reacts with immobilized Ru(bpy)₃²⁺ to generate ECL emission. Among the three types of design including two-layer, mixed and sandwich configuration, the sandwich configuration showed the best sensitivity with the calibration range of 25-2000 μM and the limit of detection of 0.5 μM in a flow injection analysis of glucose. The alcohol-free mesoporous sol-gel and the sandwich design made the biosensor potentially applicable in flow-injection analysis of samples.     

纳米银／半胱氨酸修饰葡萄糖生物传感器的研究

为优化电流型生物传感器的性能,采用相转移法结合超声波法制备纳米银溶胶,并用透射电镜对其粒径和形态进行了表征.将纳米银/半胱氨酸与葡萄糖氧化酶(GOD)共同修饰在电极表面制成酶电极.结果表明:制备的纳米银粒子近似球形,平均直径为6.27 nm;酶电极的线性响应范围为5.0×10-5～1.5×10-3 mol/L;检出限为7.14×10-6 mol/L(S/N=3);响应时间小于5 s.4℃保存30 d,该电极仍有83.7%的初始响应电流,重复性和稳定性良好.     

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.     

Application of a functionalized parylene film as a linker layer of SPR biosensor

The surface plasmon resonance (SPR) biosensors have been used to detect various target analytes by using highly specific antigen-antibody interactions. In this work, a parylene film modified to have primary amine groups was applied as a linker layer of the SPR biosensor, and the primary amine groups were used for the covalent immobilization of proteins to the SPR biosensor. The feasibility of the parylene film as a linker layer was presented by estimating the influence of the parylene film on the SPR measurement parameters, such as the sensitivity and the detection range. Then, a model protein called horseradish peroxidase (HRP) was used to demonstrate the improved immobilization efficiency as well as the sensitivity of the SPR biosensor with the parylene-A film. Additionally, a reconstruction method of the immunoaffinity layer was presented by using oxygen plasma.     

基于纳米金颗粒放大的电化学传感器用于三聚氰胺的检测

三聚氰胺与胸腺嘧啶（T）之间能够通过三个氢键结合,以富T的DNA探针为识别元件,结合DNA修饰的纳米金颗粒放大技术,以电活性物质钌胺作为信号分子,发展了一种高灵敏检测三聚氰胺的电化学传感器,该传感器具有良好的特异性和灵敏度,检测下限低至0．5nmol／L。