基于氧化石墨烯/石墨纤维微电极的microRNA自驱动传感器的研制

MicroRNAs are promising biomarkers for detection of various types of cancer. Electrochemical microRNA sensor has its unique advantages, but its sensitivity and stability needs to be further improved. Nanogenerators can harvest energy from the environment to power the sensors. Combining nanogenerators with sensors and developing self-powered, implantable microRNA sensors have important significance for the early diagnosis and treatment of cancer. The previous work of our group found that abundant graphene oxide (GO) sheets can be obtained on the surface of graphite fiber when it was oxided. The GO/graphite fiber composites have the potential to be used directly as the work electrode of electrochemical biosensor. In this project, the electrochemical characters of the GO/graphite fiber composites will be studied. The composites which have the characters of simple preparation, high electrochemical performance and low-cost will be obtained for electrode application, and a sensitive and stable microRNA sensor will be constructed based on this electrode material. A nanogenerator with high power will be developed by designing the materials for the opposite sides and controlling the micro-structure and surface morphology. Through combining nanogenerators with the as-prepared microRNA sensors, a prototype device of self-powered microRNA sensor will be developed. This study will lay the foundation of theory and technology for the development of implantable, wireless, practical microRNA biosensor.

MicroRNA是一种极具前景的新型癌症标志物，电化学microRNA传感器具有独特优势，但灵敏性和稳定性需进一步提高。纳米发电机可从环境中捕获能量驱动传感器。将microRNA传感器与纳米发电机联合，发展自驱动、可植入的microRNA传感器，对癌症的早期诊断和治疗具有重要意义。项目组前期工作发现，将石墨纤维氧化可在其表面得到大量的氧化石墨烯（GO）片层， 该GO/石墨纤维复合材料有望直接用作传感器的工作电极。本项目通过对GO/石墨纤维材料电化学特性的研究，得到制备简单、性能优良、价格低廉的电极材料，进而构建灵敏、稳定的microRNA微纳传感器；通过材料设计、微结构调控等手段构建高功率的纳米发电机；通过与microRNA传感器联用，完善信号检测机制，最终建立自驱动microRNA传感器的原型器件。为下一步进行可植入的无线传输的实用化microRNA生物传感器件的研制奠定理论与技术基础。

石墨纤维非常适合体内研究，但其表面具有较少的活性位点，因此通过改良的Hummers方法在石墨纤维表面原位合成GO的片层结构，制备了具有翘曲鳞片状结构的氧化石墨烯/石墨纤维复合结构材料，通过研究其在不同氧化条件下氧化石墨烯形成的化学及形貌学变化规律，研究了该材料在微纳尺度下的电化学特性；并基于此材料，分别构建了灵敏的microRNA传感器、DNA传感器、葡萄糖传感器，并应用其类似物二硫化钨构建ATP及汞离子传感器。通过研究纳米发电机摩擦表面材料的性质、结构、形貌对表面电荷的产生、储存及传输过程的影响机制，设计制备了高性能的摩擦纳米发电机，并应用摩擦纳米发电机提供电源，分别构建了一个自驱动的光催化系统和一个自供电的电刺激辅助骨髓间充质干细胞神经分化系统；构建基于金红石/锐钛矿TiO2（R/A- TiO2）异构纳米树阵列的高性能、自驱动、无线的光电探测器，在无线信号传输方面进行了探索。