Direct electrochemistry and electrocatalysis of horseradish peroxidase in MnO_2 nanosheet film

A novel material MnO2 nanosheet has been used as the support matrix for the immobilization of horseradish peroxidase (HRP). HRP entrapped in MnO2 nanosheet film exhibits facile direct electron transfer with the electron transfer rate constant of 6.86 s-1. The HRP/MnO2 nanosheet film gives a re- versible redox couple with the apparent formal peak potential (E0′) of -0.315 V (vs. Ag/AgCl) in pH 6.5 phosphate buffer solution (PBS). The formal potential E0′ of HRP shifts linearly with pH with a slope of -53.75 mV·pH-1, denoting that an electron transfer accompanies single-proton transportation. The immobilized HRP shows an electrocatalytic activity to the reduction of H2O2. The response time of the biosensor for H2O2 is less than 3 s, and the detection limit is 0.21 μmol·L-1 based on signal/noise = 3.     

辣根过氧化物酶修饰电极的电化学研究

制备了考马斯亮蓝和多壁碳纳米管混合物修饰玻碳电极（CBB G-250/MWNT/GC）,考察了固定在该修饰电极上的辣根过氧化物酶的电子转移情况。结果表明,辣根过氧化物酶在该电极上实现了稳定的直接电子转移反应,循环伏安图上出现了一对对称性良好的氧化还原峰。直接电子转移反应的表观速率常数k_s=4.68s^-1,式量电位E^0′几乎不随扫速（至少在20～270mV/s的扫速范围内）而变化,平均值为（-0.333±0.002）V（参比Ag/AgCl pH 7.0）。式量电位和pH的良好的线性关系表明该修饰电极上辣根过氧化物酶的直接电化学反应是有质子参与的。实验结果还证实了该修饰电极上酶对底物H₂O₂有良好的电催化活性。该方法可为生物传感器和生物燃料电池酶电极的制备提供基础数据。     

辣根过氧化物酶催化反应产物的电化学行为

用多种电化学分析方法研究了辣根过氧化物酶催化反应产物 2 ,3-二氨基吩嗪 (DAP)的电化学行为。在不同介质中探讨了测定 DAP的灵敏度 ,并在 p H9.1 5的 Britton- Robinson缓冲溶液中研究了 DAP电化学还原的电极过程。实验表明 ,在 p H9.1 5的 Briton- Robinson缓冲溶液中 ,DAP在滴汞电极上的还原为一不可逆的 ,非吸附的双电子还原过程     

血红素类蛋白质-纳米氧化铝-金胶自组装体系的直接电化学与电催化

三种血红素类蛋白质--细胞色素c、肌红蛋白、血红蛋白,被固定在纳米氧化铝-金胶自组装体系修饰玻碳电极表面,紫外光谱实验结果表明固定在纳米氧化铝-金胶表面的蛋白质保持其原始的二级结构不变.用电化学阻抗光谱和循环伏安技术表征了界面的组装过程及其电化学性质,结果表明纳米氧化铝-金胶模板不仅为蛋白质固定提供了良好的环境,而且加快了蛋白质分子与电极之间的电子转移.讨论了扫描速度对细胞色素c电化学行为的影响及其对过氧化氢的电催化还原等性质.     

基于Pt-Au-MoS2-ITO传感器对于H2O2的还原检测

实验探究了二硫化钼（MoS₂）作为一种新型材料与贵金属纳米粒子金（Au）、铂（Pt）的复合基底对于过氧化氢（H₂O₂）的还原性检测,采用氧化铟锡导电玻璃（ITO）作为电极,制备出了基于Pt-Au-MoS₂-ITO的生物传感器,为H₂O₂还原性检测的便携性操作打下了基础.实验采用电化学沉积的方法制备材料,同时使用循环伏安（CV）法、计时电流法等传统电化学手段表征了传感器电化学性能,采用场发射扫描电子显微镜（FE-SEM）来表征传感器表面形貌.建立了用于H₂O₂还原检测的、具有高检测限、高灵敏度和宽检测范围的传感器.     

石墨电极上琼脂糖膜固载血红蛋白的电化学性能研究

用琼脂糖(agarose)将血红蛋白(Hb)固定在热裂解石墨电极表面,制备了Hb-agaose膜修饰电极.包埋在琼脂糖中的血红蛋白与电极直接传递电子.在磷酸盐缓冲溶液中得到一对可逆的血红蛋白辅基血红素Fe(Ⅲ)/Fe(Ⅱ)电对氧化还原峰,式电势为-0.299 V(vs SCE),式电势随缓冲溶液pH值增加而负移且成线性关系,直线斜率为-44 mV/pH,说明血红蛋白的电子传递过程伴随有质子的转移.并研究了Hb-agarose膜修饰电极对H2O2的电催化性质.     

共价修饰的辣根过氧化物酶及其在酶传感器中的应用

将介体对甲酰苯基二茂铁（ＦＰＦ）与辣根过氧化物酶（ＨＲＰ）共价结合,然后同单体吡咯一起电聚合到铂电极上,再通过戊二醛将葡萄糖氧化酶（ＧＯＤ）交联固定在电极上,制成共价修饰的ＨＲＰ／ＧＯＤ介体酶传感器。共价修饰的酶传感器响应电流增大,底物测试范围０～４０ｍｍｏｌ／Ｌ,电极稳定性增强。     

植酸钛纳米材料固定酶制备过氧化氢传感器

利用植酸盐分子中磷酸基团与部分金属离子的强络合能力,通过微波合成法合成植酸钛纳米材料,并运用这种材料结合混合滴涂的方法将辣根过氧化物酶成功修饰到玻碳电极表面.运用紫外-可见光谱和电化学,实验结果证明了这种材料具有良好的生物相容性,有利于防止酶在固定化过程中生物活性的损害.此法制备的生物传感器实现了辣根过氧化物酶(HRP)和玻碳电极之间的直接电子转移,且对过氧化氢呈现出良好的催化还原作用,对H2O2检测的响应电流线性范围是6.67×10-7~4.73×10-5mol·L-1,线性相关系数R=0.9988(n=20),检测限为4.0×10-7mol·L-1(S/N=3),米氏常数(Kapp M)为0.036 mmol·L-1.所制得的生物传感器呈现出良好的重现性和稳定性.     

辣根过氧化物酶在石墨电极上的固定化及其对H_2O_2的响应

基础电极的选择和酶、抗体、DNA等生物活性分子的固定化方法都是影响生物传感器性能的关键因素.以石墨电极(GE)为基础电极,基于辣根过氧化物酶(HRP)对H2O2氧化邻苯二胺(OPD)生成2,3-二氨基吩嗪(DAP)反应体系的高效催化作用,研究了HRP固定化技术.分别利用再生丝素、聚乙二醇、壳聚糖包埋固定HRP,并以HRP修饰GE为指示电极,通过电位法测定H2O2浓度,对不同的固定化方法进行评价.结果表明,利用再生丝素包埋法制备的HRP/GE电极对H2O2具有更好响应性能,其工作曲线斜率为54.97,检测下限为8.82×10-8 mol.dm-3,线性范围为3.53×10-7～8.82×10-4 mol.dm-3.所提出的HRP/GE具有制备简单、成本低廉、响应快、灵敏度高等优良性能,具有较好的应用前景.     

ZnONPs增敏流动注射化学发光法检测雨水中的H2O2

基于ZnO纳米颗粒(ZnO nanoparticles,ZnO NPs)增敏luminol-H_2O_2化学发光,结合流动注射技术,研究建立一种简单、快速、灵敏地测定雨水中微量H_2O_2的方法。考察pH,ZnO NPs、luminol和H_2O_2浓度对化学发光的影响。在优化条件下,H_2O_2浓度在0.06~20μmol/L范围内,H_2O_2浓度的对数(lg c)和化学发光峰面积的对数(lg A)具有良好的线性关系,检出限(LOD)为0.016μmol/L(3σ)。将此方法应用于雨水中微量H_2O_2的测定,回收率为95%~102%,RSD(n=11)为2.41%。     

植物叶片H_2O_2胁迫应答蛋白质组学分析

植物叶片是感知外界H_2O_2胁迫信号的重要器官.整合分析了水稻(Oryza sativa)、小麦(Triticum aestivum)、二穗短柄草(Brachypodium distachyon)和柑橘(Citrus aurantium)在应对不同程度H_2O_2胁迫时蛋白质表达模式的变化特征.阐明了H_2O_2胁迫应答网络体系中的信号与代谢通路(如:光合作用、糖类与能量代谢、转录调控、蛋白质合成与命运、胁迫防御、信号转导和基础代谢等)的变化及植物叶片应答H_2O_2胁迫的分子调控机制.     

基于MoS2模拟酶检测可口可乐饮料中的磷酸根

Mo S2纳米片具有类辣根过氧化物酶的催化活性,能高效地催化过氧化氢氧化底物3,3',5,5'-四甲基联苯胺(TMB)产生蓝色产物.利用磷酸根能够降低MoS2纳米片催化活性的原理,建立了一种检测磷酸根的比色传感体系并用于可口可乐饮料样品的检测.实验考察并优化了温度、p H值、TMB浓度及H2O2浓度等参数影响,在最优条件(温度45℃、p H 5.0、TMB 25 mmol·L-1、H2O230 mmol·L-1)下,磷酸根浓度在2~40μmol·L-1范围内与吸光度具有良好的线性关系,检测限(3σ/k)为0.79μmol·L-1.     

O3/H2O2工艺控制太湖原水中致嗅氨基酸

针对太湖原水中氨基酸氯化消毒后可能引发的嗅味问题,采用太湖某水厂滤后水为研究对象,考察了O₃/H₂O₂深度处理工艺对水中致嗅氨基酸的去除效果及影响因素。结果表明滤后水中致嗅氨基酸占总游离氨基酸的81.6%,采用O₃/H₂O₂工艺降解致嗅氨基酸的最佳投量为1.5 mg·L^-1O₃和0.06 mM H₂O₂,去除率91.28%,致嗅氨基酸浓度降至484.62ng·L^-1,加氯消毒后几乎没有致嗅风险。水温10～30℃范围内,O₃/H₂O₂对致嗅氨基酸的去除率随温度升高而增大;pH=6～8范围内,去除率随p H的升高而增大。另外,该组合工艺较单独O₃/H₂O₂对溴酸盐的生成也有明显抑制作用。     

基于透明微针拉曼原位检测H2O2

在聚甲基丙烯酸甲酯-微针（PMMA-MNs）阵列上修饰聚多巴胺（PDA）层,通过离心技术将金纳米粒子（Au NPs）组装在MNs表面,构建纳米金@聚多巴胺@聚甲基丙烯酸甲酯微针阵列（Au@PDA@MNs）.Au@PDA@MNs有强表面增强拉曼散射（SERS）效应,以罗丹明6G（R6G）作为拉曼探针,在10^-4~10^-8 mol·L^-1的范围内有良好的线性响应,检测限（LOD）可达3.1×10^-10 mol·L^-1.为了检测过氧化氢（H₂O₂）,4-巯基苯硼酸（4-MPBA）被修饰在Au@PDA@MNs上以构建功能化的MNs.利用4-MPBA分子氧化生成4-羟基硫代苯酚（4-HTP）和MNs的透光性,基于1 000 cm^-1和1 068 cm^-1处拉曼强度比（I_{1 000}/I_{1 068}）的变化,完成了H₂O₂的拉曼定量检测,I_{1 000}/I_{1 068}的变化与H₂O₂浓度成定量关系.线性响应范围为10~2 000 μmol·L^-1,LOD为0.93 μmol·L^-1.MNs和SERS技术的结合为确定具有短半衰期和弱拉曼信号的疾病相关生物标志物开辟了一条新途径.     

Resistless photochemical etching of a silicon wafer by UV laser with an H<Superscript>2</Superscript>O<Superscript>2</Superscript> and HF aqueous solution

A new resistless etching method has been developed for Silicon wafers. This new method uses an aqueous solution consisting of hydrogen peroxide (H₂O₂) and hydrogen fluoride (HF) as the activating etchants. A 193 nm ArF excimer laser and a 266 nm fourth harmonic generation Nd: YAG laser were used as the photon sources. Results showed that pattern etching has been achieved without any photoresist film. In the case of the 193 nm laser, the optimal etching appeared at a 1.3 H₂O₂÷HF ratio, where an etch depth of 210 nm was achieved with a fluence of 29 mJ/cm² and shot number of 10000. At the same conditions, the etch depth with H₂O₂ and HF solution was three times of that by using H₂O and HF mixture. In the case of the 266 nm Nd: YAG laser, the optimal etching appeared at twice ratio of H₂O₂/HF, where the etch depth of 420 nm was achieved with a fluence of 12 mJ/cm² and shot number of 30000. Results showed that the etch effect of the 266 nm Nd: YAG laser was more desirable than that of the 193 nm ArF excimer laser.     

Involvement of NADPH oxidase NtrbohD in the rapid production of H2O2 induced by ABA in cultured tobacco cell line BY-2

The mechanisms for the production of hydrogen peroxide (H₂O₂) induced by abscisic acid (ABA) were investigated in suspension culture cells of tobacco BY-2 cells. The results showed that the immediate generation of H₂O₂, which was mainly derived from superoxide dismutase-catalyzed dismutation of superoxide radical, was significantly induced by ABA. Furthermore, treatment of the cultured tobacco cells with ABA resulted in a time-dependent quick increase in plasma membrane (PM) NADPH oxidase activity, which coincided on time and magnitude with the elevation in ABA-induced accumulation of H₂O₂. Moreover, these enhanced effects were pronouncedly inhibited by two NADPH oxidase inhibitor, diphenylene iodonium and imidazole, suggesting that PM NADPH oxidase is involved in the rapid accumulation of ₂O₂ in cultured tobacco cells. In addition, analysis of the expression level of NtrbohD, a PM NADPH oxidase gene in tobacco, by RT-PCR and protein gel blot revealed that the gene at both mRNA and protein levels was upregulated by ABA, indicating that NtrbohD participates in the ABA-stimulated rapid production of H₂O₂ in tobacco culture cells. Taken together, these findings suggest that ABA induces the rapid accumulation of reactive oxygen species via NADPH oxidase in suspension culture cells of tobacco, and that NADPH oxidase and H₂O₂ appear to be important components in ABA signal transduction pathway in plants.     

Involvement of NADPH oxidase NtrbohD in the rapid production of H2O2 induced by ABA in cultured tobacco cell line BY-2

The mechanisms for the production of hydrogen peroxide (H₂O₂) induced by abscisic acid (ABA) were investigated in suspension culture cells of tobacco BY-2 cells. The results showed that the immediate generation of H₂O₂, which was mainly derived from superoxide dismutase-catalyzed dismutation of superoxide radical, was significantly induced by ABA. Furthermore, treatment of the cultured tobacco cells with ABA resulted in a time-dependent quick increase in plasma membrane (PM) NADPH oxidase activity, which coincided on time and magnitude with the elevation in ABA-induced accumulation of H₂O₂. Moreover, these enhanced effects were pronouncedly inhibited by two NADPH oxidase inhibitor, diphenylene iodonium and imidazole, suggesting that PM NADPH oxidase is involved in the rapid accumulation of ₂O₂ in cultured tobacco cells. In addition, analysis of the expression level of NtrbohD, a PM NADPH oxidase gene in tobacco, by RT-PCR and protein gel blot revealed that the gene at both mRNA and protein levels was upregulated by ABA, indicating that NtrbohD participates in the ABA-stimulated rapid production of H₂O₂ in tobacco culture cells. Taken together, these findings suggest that ABA induces the rapid accumulation of reactive oxygen species via NADPH oxidase in suspension culture cells of tobacco, and that NADPH oxidase and H₂O₂ appear to be important components in ABA signal transduction pathway in plants.     

基于植酸锆/普鲁士蓝复合膜的电催化行为研究

通过层层自组装技术,构建植酸锆/普鲁士蓝(Zr-IP_6/PB)多层结构膜.基于普鲁士蓝(PB)对双氧水(H_2O_2)有很高的电催化性能,加之5层植酸锆/普鲁士蓝膜多孔结构有利于传质过程,该H_2O_2传感器具有高灵敏度和高选择性.实验结果显示:修饰电极对H_2O_2响应的物质的量浓度范围为2.00×10~(-5)～1.76×10~(-3) mol·L~(-1),线性相关系数R=0.998 9.