具有能量供给与生物传感协同功能的纤维素基自供能血糖传感器研究

Self-powered biosensor provides guarantee of steady work of implantable blood glucose sensor in human body. In view of the present problems of self-powered biosensors such as poor biocompatibility, low sensitivity, uncontrolled detection linear range, in this project, bacterial cellulose (BC) with excellent biocompatibility is used as substrate material, which will be combined with graphene (rGO) and nanogold (Au) to prepare conductive bacterial cellulose membrane functionalized by nanogold. After that, glucose oxidase and laccase are immobilized on Au/BC/rGO as anode and cathode, respectively, which are further combined with separator (metal salt doped BC membrane) to construct novel self-powered sensor. We will study the influence factors and change rule on the conductivity of BC/rGO membrane, explore the control mechanism of nuclear growth of nanogold, analyze the influence rules of conditions for enzyme immobilization on capacity and activity of enzyme; clarify the synergistic catalytic mechanism of enzyme, nanogold, and graphene towards glucose, explore the effect rule of the synergetic function of energy supply and biosensing, reveal the sensitization mechanism of sensor, establish kinetics equation of biocatalysis reaction; systematically study the effect of preparation parameters and external environment on the sensor performance, establish controllable adjustment models of sensitivity and detection range of self-powered blood glucose sensor, provide new idea and theoretical basis for exploiting novel implantable self-powered blood glucose sensor.

自供能生物传感器为植入式血糖传感器在人体内的持续稳定工作提供了保障。针对目前自供能生物传感器材质生物相容性较差、灵敏度低及检测线性范围不可控等问题，本项目拟使用生物相容性优异的细菌纤维素(BC)为基材，将BC与石墨烯(rGO)、纳米金(Au)结合制备纳米金功能化的导电细菌纤维素膜，分别固定葡萄糖氧化酶和漆酶作为阳极和阴极，并以掺杂金属盐的BC膜为隔膜构建新型自供能血糖传感器。研究BC/rGO膜电导率的影响因素和变化规律，探索纳米金成核生长的控制机理，分析固定化条件对酶负载量及酶活的影响规律；阐明生物酶、纳米金及石墨烯对葡萄糖分子的协同催化机制，探究能量供给与生物传感间的协同功能作用规律，揭示传感器增敏机理，建立生物催化反应动力学方程；系统研究制备参数及外界环境对传感器检测性能的影响，建立自供能血糖传感器检测范围的可控调节模型，为开发新型植入式自供能血糖传感器提供新思路和理论依据。

近年来，生物传感器因其低成本、易制作、高效、迅速、灵敏度高等优点，被广泛应用于环境监控、血糖检测以及食品监督等领域。然而，大多数生物传感器仍存在离不开外加能源的问题，这极大的限制了生物传感器应用和发展，为了实现实时、快速、便携式分析检测，构建低成本和小型化的自供能传感器具有十分重要的意义。本研究利用新兴的酶生物燃料电池技术结合生物手段和一维纳米碳（羧基化多壁碳纳米管，c-MWCNTs）材料优势，构建新型自供能传感器且应用于葡萄糖检测。通过在BC/c-MWCNTs复合材料表面可控沉积纳米金（AuNPs），得到BC/c-MWCNTs/AuNPs柔性电极。结合静电自组装方法，分别在柔性电极上固定Lac和GOx，得到酶固定化生物阴、阳极，构建了BC柔性基葡萄糖/O2自供能生物传感器。通过选择了不同的目标因子和模拟人体血液中共存的目标因子，进行了单因子和多因子测试。实验结果表明，所构建的自供能生物传感器具备很好的抗干扰性和高选择性。同时，所构建的葡萄糖/O2自供能生物传感器具有较高的输出功率密度（345.14 µW·cm-3）且对葡萄糖具有宽的检测范围（0-50 mM）和低的检出限（2.874×10-3 mM）。主要归因于c-MWCNTs和AuNPs优良的理化特性，实现了两者间的相互协同效应，更好地促进了酶的直接电子转移，实现了电子从酶蛋白分子的活性中心到电极表面的转移。BC/c-MWCNTs/AuNPs作为柔性电极在自供电生物传感器领域具有潜在的应用前景，为人体血糖的检测奠定了理论依据和技术支持。