The effect of the layer structure on the activity of immobilized enzymes in ultrathin films
The effect of the layer structure on the activity of immobilized enzymes in ultrathin films
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DOI：
10.1016/j.jcis.2006.07.013
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发表时间：
2006-11-01
影响因子：
9.9
通讯作者：
Oliveira, Osvaldo N., Jr.
中科院分区：
文献类型：
--
作者：
Caseli, Luciano;dos Santos, David S., Jr.;Oliveira, Osvaldo N., Jr.
利用逐层（LbL）方法制造薄膜的分子工程能力，将葡萄糖氧化酶（GOD）固定在具有交替壳聚糖层的薄膜中。壳聚糖被证明是一种良好的支架材料，因为 GOD 分子保留了其对葡萄糖氧化的催化活性。通过电化学测量，我们发现壳聚糖/GOD LbL薄膜可用于检测葡萄糖，其检测限为0.2 mmol l(-1)，活性为40.5 mu A mmol(-1) L mu g(-1)，与文献中先前报道的其他传感器相比，其灵敏度很高。当仅顶层含有 GOD 时，LbL 薄膜的灵敏度达到最高，这表明内层中的 GOD 对葡萄糖氧化没有贡献，可能是因为它阻碍了分析物扩散和电子通过沉积层的传输。这可以通过 LbL 膜中 GOD 分子与壳聚糖的紧密堆积来解释，正如使用石英晶体微天平估计每层吸附的 GOD 量推断的那样。 (c) 2006 Elsevier Inc. 保留所有权利。
The molecular engineering capability of the layer-by-layer (LbL) method for fabricating thin films has been exploited in order to immobilize glucose oxidase (GOD) in films with alternating layers of chitosan. Chitosan was proven a good scaffolding material, as GOD molecules preserved their catalytic activity towards glucose oxidation. Using electrochemical measurements, we showed that chitosan/GOD LbL films can be used to detect glucose with a limit of detection of 0.2 mmol l(-1) and an activity of 40.5 mu A mmol(-1) L mu g(-1), which is highly sensitive when compared to other sensors in previous reports in the literature. The highest sensitivity of the LbL film was achieved when only the top layer contained GOD, thus indicating that GOD in inner layers did not contribute to glucose oxidation, probably because it hampers analyte diffusion and electron transport through the deposited layers. This may be explained by the dense packing of GOD molecules in the LbL films with chitosan, as inferred from estimates of the amount of GOD adsorbed per layer using a quartz crystal microbalance. (c) 2006 Elsevier Inc. All rights reserved.