Adsorption of glucose oxidase onto plasma-polymerized film characterized by atomic force microscopy, quartz crystal microbalance, and electrochemical measurement
Adsorption of glucose oxidase onto plasma-polymerized film characterized by atomic force microscopy, quartz crystal microbalance, and electrochemical measurement
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DOI：
10.1021/jp063755m
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发表时间：
2006-12-28
影响因子：
3.3
通讯作者：
Matsumura, Kazunari
中科院分区：
文献类型：
--
作者：
Muguruma, Hitoshi;Kase, Yoshihiro;Matsumura, Kazunari
利用原子力显微镜（AFM）、石英晶体微天平（QCM）和电化学测试等手段研究了葡萄糖氧化酶（GOD）在纳米等离子体聚合薄膜（PPF）上的吸附行为。PPF表面非常平坦（粗糙度小于1 nm），其性质（电荷和润湿性）可以很容易地改变，同时保留骨架结构。我们专注于三种类型的表面：（1）六甲基二硅氧烷（HMDS）PPF的原始表面（疏水和中性表面），（2）用氮等离子体处理的HMDS PPF表面（亲水和带正电的表面），和（3）用氧等离子体处理的HMDS PPF表面（亲水和带负电的表面）。AFM图像显示GOD分子密集地吸附在表面2上，并且可以观察到单个GOD分子。由于静电缔合作用，GOD椭球分子的长轴平行于表面排列，称为“卧位”。在表面1上，GOD分子簇没有完全覆盖原始PPF表面（表面覆盖率约为100%）。60%）。GOD簇和PPF表面之间的10 nm大小的台阶高度表明，单个GOD分子的长轴垂直于表面排列，称为“站立位置”。在表面3上，由于静电排斥，只有少数GOD分子被吸附。这些结果表明，等离子体聚合过程可以促进蛋白质吸附的增强或减少。原子力显微镜图像显示出与QCM轮廓相对应的趋势。QCM数据表明吸附行为符合Langmuir等温方程。铂电极上的GOD吸附的PPF的电流型生物传感器特性显示，由于与葡萄糖添加的酶促反应，在电流中的增量，这表明酶活性大部分保留，尽管不可逆的吸附。
Adsorption of glucose oxidase (GOD) onto plasma-polymerized thin films (PPF) with nanoscale thickness was characterized by atomic force microscopy (AFM), quartz crystal microbalance (QCM), and electrochemical measurements. The PPF surface is very flat (less than 1-nm roughness), and its properties (charge and wettability) can be easily changed while retaining the backbone structure. We focused on three types of surfaces: (1) the pristine surface of hexamethyldisiloxane (HMDS) PPF (hydrophobic and neutral surface), (2) an HMDS PPF surface with nitrogen-plasma treatment (hydrophilic and positive-charged surface), and (3) an HMDS PPF surface treated with oxygen plasma (hydrophilic and negative-charged surface). The AFM image showed that the GOD molecules were densely adsorbed onto surface 2 and that individual GOD molecules could be observed. The longer axis of GOD ellipsoid molecules were aligned parallel to the surface, called the "lying position", because of electrostatic association. On surface 1, clusters of GOD molecules did not completely cover the original PPF surface (surface coverage was ca. 60%). The 10-nm-size step height between the GOD clusters and the PPF surface suggests that the longer axes of individual GOD molecules were aligned perpendicular to the surface, called the "standing position". On surface 3, only a few of the GOD molecules were adsorbed because of electrostatic repulsion. These results indicate that the plasma polymerization process can facilitate enhancement or reduction of protein adsorption. The AFM images show a corresponding tendency with the QCM profiles. The QCM data indicate that the adsorption behavior obeys the Langmuir isotherm equation. The amperometric biosensor characteristics of the GOD-adsorbed PPF on a platinum electrode showed an increment in the current because of enzymatic reaction with glucose addition, indicating that enzyme activity was mostly retained in spite of irreversible adsorption.