冠心病早期预警生物标志物-microRNAs的高性能生物传感器研究

It’s a critical issue in the national economy and the people's livelihood to develop portable biosensors of microRNAs biomarkers for the early precaution of coronary heart disease. To this end, this project will focus on developing plug-in-type biosensors for the detection of microRNAs in blood samples, in hope of achieving absolute quantification, high sensitivity, high precision, fast-rate, and low cost. To realize such biosensors, non-plane bio-recognizing component will be constructed by covalently linking nucleic acid probes with doped ZnO nanowires deposited on flexible conductive substrates; high-performance GaAs-based high-electron-mobility transistor will be employed as the transducer component; and these two components will be coupled together via applying a unique design of separated-gate structure. Meanwhile, the successful implementation is mainly based on optimizing the structure parameters of the trasnsitors and the extended gates, tuning the properties of the nanowires, analyzing the surface potential of the bioreceptor pads, and device simulations. As a result, the equivalent Debye length of the non-plane bio-recognizing component, origins of the noises in the biosensors, and physical/chemical mechanisms underlying them will be clarified, so as to provide technology solutions to improve the detection limit, sensitivity, and signal-to-noise ratio of the obtained biosensors. The successful implementation of the project would provide technological support and theoretical basis whether for the construction of knowledge system of biochemical sensors based on traditional transistors or for the related bioelectronics/biosensors industry upgrading, which has important academic and practical values.

围绕冠心病早期预警microRNAs的便携式传感器这一能实现民生与经济共赢的重大需求，本项目拟以共价法在修饰掺杂氧化锌纳米线的柔性导电基底上固定核酸探针构建“纵深”型敏感识别元件、高性能GaAs基高电子迁移率晶体管为信号处理元件，采用分离延伸栅结构将两者巧妙结合开发插拔式生物传感器。实现血液样品中microRNAs的绝对定量、高灵敏度、高准确率、快捷、低成本的检测。通过晶体管器件结构和栅极构型的优化、纳米线性状的调控、敏感元件的表面电势分析、器件仿真模拟等研究手段，阐明“纵深”型敏感元件的等效德拜屏蔽长度及其关键影响因素及物理化学机制，弄清传感器噪声起源，掌握提高传感器的探测限、灵敏度、信噪比和稳定性的技术方案。本项目的成功实现有望为基于传统晶体管类信息器件的生物化学传感器知识体系的建立提供实验数据与理论依据，为相关的生物电子/生物传感产业升级提供技术支撑，具有重要的学术意义与应用价值。

围绕冠心病早期预警microRNAs的便携式传感器这一能实现民生与经济共赢的重大需求，本项目结合理论计算和实验设计，掌握了分离延伸栅GaAs基MM-HEMT器件结构参数、构型参数和制备参数，确定了至少5种以上的结构适用于生物传感器的应用。构建了双电层栅极构型的分离延伸栅GaAs基MM-HEMT生物传感器，针对多种心梗标志物，譬如cTnI、micro-RNA208以及PSA等验证EG-HEMT传感器的检测性能，达到了响应时间30s以及最小检测限1 pg/mL的指标。冠心病标志物-miR-208a的检测，该生物传感器可以检测的浓度范围为：10pM/L-1uM/L。在0.1×PBS溶液中，其阈值电压偏移和灵敏度与miR-208a浓度的对数呈良好的线性关系，且灵敏度在1 nM时可达到40%。 我们使用制备的EG-HEMT进行了病人血样分析（北大人民医院提供），通过对比临床检测数据，验证了此种生物传感器的实用前景。在ITO衬底上修饰掺杂氧化锌（ZnO）纳米棒作为基底，构筑了“纵深型”敏感识别元件。通过前驱体溶液浓度、温度、反应时间及衬底处理这四方面的调控，获得了不同形貌的ZnO纳米棒。尝试了ZnO纳米棒识别元件与HEMT器件相连构筑生物传感器，获得了初步的探测性能。