集成纳米机器人的蛋白质折叠密码破译芯片设计与制造的基础理论研究

Diseases, including Parkinson’s disease and Alzheimer's disease, caused by protein folding have become a great threat to the health of old people, which will impose an additional burden to the patient's family. Investigation of the dynamic process of protein folding (unfolding) and misfolding is essentially significant as it will help to unveil the mystery of pathogenic mechanism of protein folding and search for an effective treatment that can cure those diseases. In this proposal, a functionalized chip integrated with a nanorobot that offers treatment and therapy of fold diseases is designed, this chip could be potentially used to characterize the folding states of a protein and identify the protein folding pathways. The chip is composed of a silicon nitride membrane with five nanopores and a nanorobot. All the five nanopores are coated with gold gate electrodes. Four nanopores located in the corners of a square are used to drive the motion of the nanorobot, while the nanopore located at the center of the square is used for protein sensing. The nanorobot is composed of four double-stranded DNAs and a nanoparticle, the nanoparticle acts as a manipulator that also connects the target protein molecules. By tuning the bias voltage on the gate electrode, the strength as well as the direction of the electroosmotic flow could be well controlled, thus the precise manipulation of the target protein could be realized by controlling the motion of the manipulator，which can keep the target protein residing inside the nanopore sensing region. The proposed chip integrated with a nanopore sensor and a nanorobot is featured with easy fabrication, low cost and high precision, which has the most potential to be widely used for human diagnosis in the near future.

包括帕金森病和老年痴呆症等疾病在内的蛋白质折叠病严重威胁到了老年人群的健康，甚至会增加患者家庭的负担。研究蛋白质（解）折叠和错误折叠的过程及规律对破解蛋白质折叠密码科学意义重大，对阐明蛋白质折叠病的致病机制和寻求有效的治疗方法至关重要。本项目提出设计研发一种内部集成有纳米机器人的蛋白质折叠病诊疗芯片，用于检测蛋白质的折叠状态和识别其折叠路径。该芯片主要由修饰有门电极的五纳米孔氮化硅薄膜（其中四个纳米孔位于矩形顶点用于驱动纳米机器人，一个纳米孔位于矩形几何中心作为蛋白质检测单元）以及DNA/纳米颗粒组装而成的纳米机器人组成，纳米颗粒作为机械手与待测蛋白质连接。通过调节门电极的电位控制矩形顶点四个纳米孔的电渗流强度和方向，结合电泳驱动可以控制机械手的运动从而实现对待测蛋白质的精准操控，使其稳定在矩形中心的纳米孔传感区。该芯片具有易集成制造、成本低和精度高等优点，将被广泛运用，造福人类。

基于微纳机电系统MEMS/NEMS开展微纳尺度流体传感和驱动的研究有助于解决人类对智能检测、精准医疗领域的重大需求。项目团队在纳米通道内离子输运机制与应用研究方面，通过分子动力学模拟对离子电流与纳米孔几何形状的对应关系进行了系统的研究，结合离子电导率分布和传统欧姆定律提出了计算具有不同亲疏水性和纳米孔形状的离子电流精确计算模型；研究了使用串联纳米孔系统泵送离子的可行性，通过调控纳米孔阵列数和纳米孔表面电荷密度实现了纳米孔空腔的高效脱盐。在基于纳米孔的单分子检测和测序方面，通过仿真技术系统研究了DNA碱基扰动离子电流的机理，新探索了MspA纳米孔的有效传感区并实现了DNA的单碱基辨识；基于类苯分子与MoS2薄膜的强相互作用，通过调控多肽中类苯残基的含量，使得蛋白质过孔速度降低了一个量级，实现了蛋白质的检测。在纳米流体中的单分子驱动与操控技术方面，提出将原子力显微镜与纳米孔传感系统进行集成，控制DNA通过固态纳米孔的速度并提高DNA检测的灵敏度；理论设计了MoS2/SnS2异质结构检测平台，驱动多肽沿着设计的异质结构路径将蛋白质移动到目标纳米孔并实现了多肽组分的辨识；通过向溶液中添加含疏水链的DDM与蛋白质疏水氨基酸结合，使蛋白质分子通过MoS2纳米孔的速度降低一个数量级，而且不影响对单个氨基酸的区分。在基于阵列纳米孔驱动的纳米颗粒-DNA自组装纳米机器人设计方面，从理论上设计了一个纳米颗粒-DNA自组装的纳米机器人，可以沿着固态膜表面移动，结合电泳和电渗可用于驱动纳米机器人沿石墨烯膜表面在所需方向上移动；通过进一步预设操控策略，简单地切换纳米孔编码和外加电场，实现了包括纳米机器人捕获、释放、跳跃和爬行的多模式智能驱动。本文的研究有望在不久的将来实现集成微纳操控技术的精准医疗，造福人类。