Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea.
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
ACS Appl Mater Interfaces. 2017 Apr 26;9(16):14216-14221. doi: 10.1021/acsami.7b00848. Epub 2017 Apr 11.
We report the role of defects in enzymatic graphene field-effect transistor sensors by introducing engineered defects in graphene channels. Compared with conventional graphene sensors (Gr sensors), graphene mesh sensors (GM sensors), with an array of circular holes, initially exhibited a higher irreversible response to glucose, involving strong chemisorption to edge defects. However, after immobilization of glucose oxidase, the irreversibility of the responses was substantially diminished, without any reduction in the sensitivity of the GM sensors (i.e., -0.53 mV/mM for the GM sensor vs -0.37 mV/mM for Gr sensor). Furthermore, multiple cycle operation led to rapid sensing and improved the reversibility of GM sensors. In addition, control tests with sensors containing a linker showed that sensitivity was increased in Gr sensors but decreased in GM sensors. Our findings indicate that edge defects can be used to replace linkers for immobilization of glucose oxidase and improve charge transfer across glucose oxidase-graphene interfaces.
我们通过在石墨烯通道中引入工程缺陷来研究酶石墨烯场效应晶体管传感器中缺陷的作用。与传统的石墨烯传感器（Gr 传感器）相比，具有圆形孔阵列的石墨烯网传感器（GM 传感器）最初对葡萄糖表现出更高的不可逆响应，涉及到边缘缺陷的强烈化学吸附。然而，在固定化葡萄糖氧化酶后，GM 传感器的响应不可逆性大大降低，而灵敏度没有降低（即 GM 传感器为-0.53 mV/mM，Gr 传感器为-0.37 mV/mM）。此外，多次循环操作导致快速感应，并提高了 GM 传感器的可逆性。此外，含有接头的传感器的对照测试表明，Gr 传感器的灵敏度增加，而 GM 传感器的灵敏度降低。我们的研究结果表明，边缘缺陷可用于替代接头来固定葡萄糖氧化酶，并改善葡萄糖氧化酶-石墨烯界面的电荷转移。
