摘要
利用Langmuir-Blodgett技术和溶胶-凝胶（sol-gel）法在氧化铟锡（ITO）电极表面制备了有序的纳米金/氧化锌（nano-Au/ZnO）球腔阵列,并采用扫描电镜表征了nano-Au/ZnO球腔阵列的形貌。该阵列的循环伏安曲线具有微电极特性。将辣根过氧化酶（HRP）直接固定于nano-Au/ZnO球腔微电极阵列表面的ZnO球腔内,制备了过氧化氢生物传感器。采用循环伏安法研究了HRP在该阵列上的直接电化学。在pH7.0的缓冲溶液中,其循环伏安曲线于-0.145 V和-0.230 V处出现了1对稳定的准可逆氧化-还原峰,式量电位（E0′）为-0.188 V,表明固定于传感器表面ZnO球腔内的HRP保持了良好的电化学活性,其直接电子转移速率常数为2.95 s-1。ZnO的亲水性和特有的球腔阵列结构不仅为保持HRP的生物电化学活性提供了适宜的微环境,也为固定HRP提供了大的比表面积,从而增大了HRP的负载量。制备的生物传感器对H2O2有较好的电催化作用,并在6.67×10-6~1.31×10-3mol/L范围内与响应电流呈良好的线性关系,检出限为7.3×10-7mol/L,米氏常数为0.411 mmol/L。
A long-range ordered nano-Au/zinc oxide（ZnO） cavities array was fabricated on indium-tin oxide electrode surface by Langmuir-Blodgett technique and sol-gel technique.The morphology of this array was characterized by scanning electron microscopy.The cyclic voltammetric（CV） behavior of nano-Au/ZnO cavities array was in accordance with that of microelectrode,and the array can be used as microelectrodes array for biosensor design.A hydrogen peroxide（H2O2） biosensor was obtained by directly immobilizing horseradish peroxidase（HRP） into nano-Au modified ZnO cavities.Direct electrochemistry of HRP on nano-Au/ZnO cavities array was investigated.In pH 7.0 phosphate buffer,the CV curve of HRP/nano-Au/ZnO cavities array electrode showed a pair of stable and quasi-reversible redox peaks at-0.145 V and-0.230 V.The formal potential was about-0.188 V.The result indicated that the HRP immobilized in nano-Au/ ZnO cavities still retained good electrochemistry activity.The direct electron transfer rate constant was obtained to be 2.95 s-1.The hydrophilic ZnO surface and ordered cavities structure of ZnO cavities array provided not only the suitable microenvironment for HRP to retain its bioactivity/electrochemical activity,but also the large surface area for immobilization of HRP with high load.Meanwhile,the existance of nano-gold particles also enhanced the electron transfer between HRP and the modified electrode.The prepared bio-sensor provided an excellent electro-catalysis activity for H2O2.The calibration curve was linear in the range of 6.67×10-6-1.31×10-3 mol/L for H2O2 concentration with a detection limit of 7.3×10-7 mol/L and the apparent Michaelis-Menten constant for HRP modified electrode was 0.411 mmol/L.
出处
《分析测试学报》
CAS
CSCD
北大核心
2011年第7期727-733,共7页
Journal of Instrumental Analysis
基金
国家自然科学基金资助项目(20975073)
江苏省自然科学基金资助项目(BK2008147)
关键词
纳米金
ZnO球腔阵列
微电极阵列
辣根过氧化酶
过氧化氢
nano-Au
zinc oxide cavities array
microelectrode array
horseradish peroxidase
hydrogen peroxide
