The direct electron transfer of glucose oxidase (GOx) immobilized onto the surface of the carbon nanotube (CNT)-modified glassy carbon (CNT/GC) electrode is reported. The direct electron transfer rate of GOx is greatl...The direct electron transfer of glucose oxidase (GOx) immobilized onto the surface of the carbon nanotube (CNT)-modified glassy carbon (CNT/GC) electrode is reported. The direct electron transfer rate of GOx is greatly enhanced when it was immobilized onto the surface of CNT/GC electrode. Cyclic voltammetric results show a pair of well-defined and nearly symmetric redox peaks, which corresponds to the direct electron transfer of GOx, with the formal potential (E 0′), which is almost independent on the scan rates, of about ?0.456 V (vs. SCE) in the phosphate buffer solution (pH 6.9). The apparent heterogeneous electron transfer rate constant (ks) of GOx at the CNT/GC electrode surface is estimated to be (1.74 ± 0.42) s-1, which is much higher than that reported previously. The dependence of E 0′ on solution pH indicates that the direct electron transfer of GOx is a two-electron-transfer coupled with two-proton-transfer reaction process. The experimental results also demonstrate that the immobilized GOx retains its bioelectrocatalytic activity toward the oxidation of glucose. The method presented here can be easily extended to obtain the direct electrochemistry of other enzymes or proteins.展开更多
Electrochemical behavior of cytochrome c at a bis(4-pyridyl)disulphide modified gold electrodes covered with nanoporous alumina templates was investigated. The experimental results show that the nanoporous alumina tem...Electrochemical behavior of cytochrome c at a bis(4-pyridyl)disulphide modified gold electrodes covered with nanoporous alumina templates was investigated. The experimental results show that the nanoporous alumina templates promote further the direct electron transfer of cytochrome c on the modified gold electrode, resulting in a well-defined fast votammetric response.展开更多
通过共价键作用和原位还原法制备了金纳米粒子/壳聚糖-石墨烯纳米复合材料(AuNPs/Chit-GP).利用FT-IR,UV-vis,TEM以及XRD对所合成的纳米复合物的结构和形貌进行了表征.AuNPs/Chit-GP呈现明显的正电荷,因此可通过静电相互作用固载葡萄糖...通过共价键作用和原位还原法制备了金纳米粒子/壳聚糖-石墨烯纳米复合材料(AuNPs/Chit-GP).利用FT-IR,UV-vis,TEM以及XRD对所合成的纳米复合物的结构和形貌进行了表征.AuNPs/Chit-GP呈现明显的正电荷,因此可通过静电相互作用固载葡萄糖氧化酶(GOD),并构建GOD/AuNPs/Chit-GP/GC修饰电极.该修饰电极不仅可成功地实现GOD与电极间的直接电子转移,还对葡萄糖表现出良好的催化性能.实验结果表明,其催化的线性范围为2.1～5.7μmol/L,检出限为0.7μmol/L,灵敏度为79.71 mA cm-2 mM-1.这种集金属纳米粒子、生物相容性高分子以及石墨烯为一体的纳米复合物的构筑为无媒介体的电化学生物传感器的研究提供了一个良好的平台.展开更多
The glucose oxidase (GOD) immobilized onto the surface of activated ca rbon powders at the glassy carbon electrode (GOD-C/GC) could undergo the quasi-r eversible, direct electrochemical reaction. Its formal redox pote...The glucose oxidase (GOD) immobilized onto the surface of activated ca rbon powders at the glassy carbon electrode (GOD-C/GC) could undergo the quasi-r eversible, direct electrochemical reaction. Its formal redox potential, E0′, is almost independent on the scan rates. The average value of E0′ is (-0.467 ± 0 .002) V (vs SCE) in the pH 6.8 phosphate buffer solution. Its apparent heterogen eous electron transfer rate constant (ks) is (1.18 ± 0.59) s-1, which is much h igher than that reported previously. The dependence of E0′ on the pH of the buf fer solution indicated that the direct electrochemical reaction of the immobiliz ed GOD is a two-electron transfer reaction process coupled with two-proton trans fer. The further experimental results demonstrated that the immobilized GOD reta ined its bioelectrocatalytic activity to the oxidation of β-D(+) glucose.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant No.20373027)the Foundation for Scientists Returned from Abroad directed under the Ministry of Education of China+1 种基金the Natural Science Foundation of Education Committee of Jiangsu Province(Grant No.03KJA150055)the Excellent Talent Project of Personnel Department of Nanjing City of Jiangsu Province.
文摘The direct electron transfer of glucose oxidase (GOx) immobilized onto the surface of the carbon nanotube (CNT)-modified glassy carbon (CNT/GC) electrode is reported. The direct electron transfer rate of GOx is greatly enhanced when it was immobilized onto the surface of CNT/GC electrode. Cyclic voltammetric results show a pair of well-defined and nearly symmetric redox peaks, which corresponds to the direct electron transfer of GOx, with the formal potential (E 0′), which is almost independent on the scan rates, of about ?0.456 V (vs. SCE) in the phosphate buffer solution (pH 6.9). The apparent heterogeneous electron transfer rate constant (ks) of GOx at the CNT/GC electrode surface is estimated to be (1.74 ± 0.42) s-1, which is much higher than that reported previously. The dependence of E 0′ on solution pH indicates that the direct electron transfer of GOx is a two-electron-transfer coupled with two-proton-transfer reaction process. The experimental results also demonstrate that the immobilized GOx retains its bioelectrocatalytic activity toward the oxidation of glucose. The method presented here can be easily extended to obtain the direct electrochemistry of other enzymes or proteins.
文摘通过自组装依次将纳米银粒子和辣根过氧化酶(HRP)固定到巯基乙胺(Cys)修饰的玻碳电极上,制备了HRP/Ag/Cys膜修饰电极.用交流阻抗技术表征了电极的自组装过程.用循环伏安法和计时电流法考察了HRP与电极之间的直接电化学行为及酶对过氧化氢电催化特性.电极响应对过氧化氢有良好的电催化还原性质,性能稳定,响应时间小于5 s.
文摘Electrochemical behavior of cytochrome c at a bis(4-pyridyl)disulphide modified gold electrodes covered with nanoporous alumina templates was investigated. The experimental results show that the nanoporous alumina templates promote further the direct electron transfer of cytochrome c on the modified gold electrode, resulting in a well-defined fast votammetric response.
文摘通过共价键作用和原位还原法制备了金纳米粒子/壳聚糖-石墨烯纳米复合材料(AuNPs/Chit-GP).利用FT-IR,UV-vis,TEM以及XRD对所合成的纳米复合物的结构和形貌进行了表征.AuNPs/Chit-GP呈现明显的正电荷,因此可通过静电相互作用固载葡萄糖氧化酶(GOD),并构建GOD/AuNPs/Chit-GP/GC修饰电极.该修饰电极不仅可成功地实现GOD与电极间的直接电子转移,还对葡萄糖表现出良好的催化性能.实验结果表明,其催化的线性范围为2.1～5.7μmol/L,检出限为0.7μmol/L,灵敏度为79.71 mA cm-2 mM-1.这种集金属纳米粒子、生物相容性高分子以及石墨烯为一体的纳米复合物的构筑为无媒介体的电化学生物传感器的研究提供了一个良好的平台.
文摘The glucose oxidase (GOD) immobilized onto the surface of activated ca rbon powders at the glassy carbon electrode (GOD-C/GC) could undergo the quasi-r eversible, direct electrochemical reaction. Its formal redox potential, E0′, is almost independent on the scan rates. The average value of E0′ is (-0.467 ± 0 .002) V (vs SCE) in the pH 6.8 phosphate buffer solution. Its apparent heterogen eous electron transfer rate constant (ks) is (1.18 ± 0.59) s-1, which is much h igher than that reported previously. The dependence of E0′ on the pH of the buf fer solution indicated that the direct electrochemical reaction of the immobiliz ed GOD is a two-electron transfer reaction process coupled with two-proton trans fer. The further experimental results demonstrated that the immobilized GOD reta ined its bioelectrocatalytic activity to the oxidation of β-D(+) glucose.
