层层自组装构筑三维结构石墨烯纳米复合薄膜及其电化学应用

Graphene-based nano-composites possess outstanding capability in physics and chemistry and have drawn attention in electrochemical sensing. Some questions for actual graphene applications in electrochemical biosensing are still unsolved. There is not an effective method to prepare and control graphene nano-composite films in large scale with excellent structure and property. Furthermore，the relationship between the structure of graphene-based nanofilms and property of electrochemical biosensor is not clear. Therefore, in this work, novel three-dimensional structure of graphene-based nano-composite films are prepared with the use of electrostatic layer by layer self-assembly technique. In order to optimize its electrochemical property, the condition to prepare nano-composite films will be studied as well as the relationship between microstructure and its electrochemical property will be established. The molecular recognition interface with excellent biological compatibility will be designed, so that more biomolecules with bioactivity will be immobilized on it. The mechanism of electrochemical biosensor based on graphene nano-composite films will be explored to understand the relationship between structure of graphene-based nanofilms and property of electrochemical biosensor. This study will extend the new applications for graphene- based nano-composite films and offer fundamental theory for the application in electrochemical biosensing.

石墨烯基纳米复合物具有独特的结构和优异的物理、化学特性，在电化学生物传感领域备受关注。石墨烯在电化学传感的实际应用中，仍然存在一些亟待解决的问题：如何可控制备结构和性能优异的大尺寸石墨烯基复合薄膜；明确石墨烯基复合薄膜的结构与电化学生物传感器性能之间的构效关系。针对上述问题，本课题采用层层自组装的方法构筑新型三维结构石墨烯基纳米复合薄膜，研究可控制备大尺寸复合薄膜的条件，以及复合薄膜的微结构与电化学性能之间的关系。以石墨烯基复合薄膜为基底，设计具有良好生物相容性的分子识别界面，用于定向固定生物大分子以提高生物分子的活性；通过优化工艺条件，制备选择性好、灵敏度高、可重复使用的电化学生物传感器。研究石墨烯基复合薄膜在生物传感器中的作用机制，以理解石墨烯基纳米复合薄膜的结构与生物传感性能之间的关系。本研究为拓展石墨烯基复合薄膜在电化学生物传感方面的应用提供理论依据。

本研究旨在以石墨烯、类石墨烯、贵金属纳米粒子等纳米材料为载体，借助其优异的导电、催化性能和高的比表面积等特点、克服石墨烯基复合薄膜在实际应用中的不足(重复性差、石墨烯复合膜与电化学传感器之间构效关系不明确等)构建选择性好、灵敏度高、可重复的识别H2O2、DNA、凝血酶等生物目标分子的化学传感器。基于此，我们的主要研究内容分为以下几方面：(1)通过静电吸附作用将还原氧化石墨烯与金纳米粒子层层自组装，制备石墨烯/金纳米粒子自组装多层膜，以其修饰电极构建了H2O2电化学传感器。该传感器与石墨烯/金纳米粒子复合膜构筑的H2O2传感器相比，检测限更低，线性范围略窄，并对石墨烯/金纳米粒子多层薄膜与H2O2电化学传感器之间的构效关系进行了研究。(2)研究了金纳米颗粒-二硫化钼-还原氧化石墨烯复合物构筑的电化学H2O2传感器。利用水热法制备了二硫化钼-还原石墨烯复合物，并原位还原氯金酸制备金纳米颗粒-二硫化钼-还原石墨烯复合物，该修饰电极构建的H2O2电化学传感器与第一个体系相比较，灵敏度更高，检测限更低，并对其增敏机理做了初步探讨。(3)成功地利用金纳米颗粒-二硫化钼-还原石墨烯复合物构筑检测DNA的电化学生物传感器。该复合物具有三维结构，提高了负载金纳米粒子的量，大大提高了检测目标DNA的灵敏度。(4)构筑石墨烯/金纳米棒复合薄膜，应用于灵敏检测凝血酶。该石墨烯/类石墨烯传感体系具有较好的应用价值。