三维立体结构微纳电极研究

Three-Dimensional Structured Micro/nano Electrode

基于体硅加工工艺和纳米材料技术,研制微电机系统(MEMS)尺度敏感微结构与纳米铂颗粒的复合结构,提高微电极电化学性能,制备具有三维立体微结构的安培型微电极传感器。利用硅的各向异性湿法腐蚀技术在毫米级的工作电极表面实现微米级的锥体形微池阵列,以H2O2为检测对象考察立体电极结构对传感器性能的改进效果,实验证明,立体结构的设计使传感器具有更低的检出限(8μmol/L)及更高的灵敏度(在0～200μmol/L浓度范围内检测灵敏度提高约85%),且具有较好的线性和重复性。利用电化学方法在电极表面沉积铂黑,通过微观形貌分析和电化学特性考察,比较了在平面微电极和立体微电极上修饰纳米材料的效果。立体结构为电沉积铂纳米颗粒提供了更为理想的微环境,改善了纳米材料修饰的效果;立体结构微电极与纳米颗粒的尺寸效应相结合,进一步提高了电极的催化效率和电化学特性。

Based on nanomaterials and silicon bulk micromachining technology, a three-dimensional （3D） structured microelectrodes are fabricated, comprising both platinum nanoparticles and sensitive microstructures. This three-dimensional micro structure is developed to enhance the electrochemical property of the microelectrode of amperometric biosensor. By silicon anisotropic wet etching technology, a micrometer-scale pyramidal micro pool array is formed on millimeter-scale working electrode surface. The sensor has been successfully applied to detect H2O2. The result demonstrates that 3D micro structure can enlarge the effective surface area of the working electrode. In comparison with amperometric biosensor based on planar microelectrode, this sensor has the advantages of lower detection limit （8 μmol/L） and higher current signal output. The sensitivity is enhanced by about 85% in low concentration range （0-200 μmol/L）. It provides a better microenvironment for electrodeposition of platinum nanoparticales and improves the modification effect of nanomaterials. Moreover, along with the size-dependant properties of nanostructures, this design further enhances the catalytic efficiency and the electroactivity of the electrode.