Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore.
Biosens Bioelectron. 2010 Jan 15;25(5):1102-8. doi: 10.1016/j.bios.2009.09.023. Epub 2009 Oct 1.
The development of enzyme-mediated amperometric biosensors on the indium-tin oxide (ITO) glass electrode via surface-initiated atom-transfer radical polymerization (ATRP) was investigated. A trichlorosilane coupling agent, containing the sulfonyl halide ATRP initiator, was immobilized initially on the ITO electrode surface for consecutive surface-initiated ATRP of ferrocenylmethyl methacrylate (FMMA) and glycidyl methacrylate (GMA). Glucose oxidase (GOD) was subsequently immobilized on the modified ITO electrode surface via coupling reactions between the epoxide groups of GMA and the amine groups of GOD. The surface composition after each functionalization step was ascertained by X-ray photoelectron spectroscopy (XPS). With the introduction of redox-P(FMMA) block as the electron-transfer mediator, the enzyme-mediated ITO electrode exhibits high sensitivity, as revealed by cyclic voltammetry measurement. The sensitivities of the ITO-g-P(GMA-GOD)-b-P(FMMA) and ITO-g-P(FMMA)-b-P(GMA-GOD) electrodes are about 3.6 microA/(mM cm(2)) (in the linear concentration range 0-5 mM of glucose) and 10.9 microA/(mM cm(2)) (in the linear concentration range of 0-17 mM of glucose), respectively. For both biosensors, the steady-state response time and the detection limits are estimated to be less than 20 s and 0.4+/-0.1 mM of glucose concentration, respectively. Furthermore, the spatial effect of the redox mediator on the electrode surface is revealed by the fact that the block copolymer brush-functionalized ITO electrode with P(FMMA) as the inner (first) block is more sensitive to glucose than that with P(GMA) as the inner block.
通过表面引发原子转移自由基聚合（ATRP）在氧化铟锡（ITO）玻璃电极上开发酶促安培生物传感器。首先将含有磺酰卤 ATRP 引发剂的三氯硅烷偶联剂固定在 ITO 电极表面上，以连续进行二茂铁甲基甲基丙烯酸酯（FMMA）和甲基丙烯酸缩水甘油酯（GMA）的表面引发 ATRP。随后，通过 GMA 的环氧基与 GOD 的氨基之间的偶联反应将葡萄糖氧化酶（GOD）固定在修饰后的 ITO 电极表面上。通过 X 射线光电子能谱（XPS）确定每个功能化步骤后的表面组成。通过引入氧化还原-P（FMMA）嵌段作为电子转移介质，酶促 ITO 电极表现出高灵敏度，这通过循环伏安法测量得到证实。ITO-g-P（GMA-GOD）-b-P（FMMA）和 ITO-g-P（FMMA）-b-P（GMA-GOD）电极的灵敏度分别约为 3.6 μA/（mM cm^2）（在 0-5 mM 葡萄糖的线性浓度范围内）和 10.9 μA/（mM cm^2）（在 0-17 mM 葡萄糖的线性浓度范围内）。对于这两个生物传感器，稳态响应时间和检测限估计分别小于 20 s 和 0.4+/-0.1 mM 的葡萄糖浓度。此外，通过以下事实揭示了氧化还原介质在电极表面上的空间效应：具有 P（FMMA）作为内（第一）嵌段的嵌段共聚物刷功能化 ITO 电极对葡萄糖的灵敏度高于具有 P（GMA）作为内嵌段的电极。
