仿生固态纳米孔传输动力学行为与性能调控研究

The nanometer-sized pores fabricated on solid-state membranes such as SiNx, termed as solid-state nanopores, can serve as a detecting and analyzing platform targeting analytes including metal ions, small molecules, DNA, polymer and proteins. However, although solid-state nanopores are more stable, durable and easy processing than those of their biological counterpart, i.e., protein nanopores, they present lower sensitivity and accuracy. Consequently, here we propose to construct so-called biomimetic solid-state nanopores by taking into account the three-dimensional geometry and surface properties of the high-performance biological nanopores. To explore the translocation dynamics of molecules inside these biomimetic nanopores and improve their performance in single-molecule detection, we will combine the continuum theory-based modeling, classic- and first principles- molecular dynamics as well as necessary experiments to study the modeling and simulating techniques of the biomimetic nanopore system as well as abnormal behaviors and translocation dynamics of ions and molecules confined in biomimetic nanopores, in order to unveil the regulating mechanism of the single-molecule sensing capability of biomimetic nanopores and thereby provide the theoretic basis for the optimization and simplification of biomimetic nanopore-based devices.

氮化硅等固态膜上直径为纳米尺度的孔道（简称固态纳米孔）可用于金属离子、小分子、DNA分子、聚合物和蛋白质等物质的检测和分析。然而，尽管固态纳米孔具有远高于其生物学同类（即蛋白纳米孔）的稳定性、耐久性和易加工性，其检测敏感性和准确性还弱于蛋白纳米孔。因此，本项目提出参照生物纳米孔三维结构、表面电性和亲疏水性等关键特性，构建相应仿生固态纳米孔。针对仿生固态纳米孔中分子的传输动力学行为及单分子检测性能调控这一关键问题，拟采用连续介质理论建模、经典和第一原理分子动力学模拟计算，并结合必要的实验探索等研究手段，对仿生固态纳米孔体系的建模和模拟技术、受限在仿生固态纳米孔内的离子、分子的反常动力学行为、仿生固态纳米孔的传输动力学特性等科学问题开展深入研究，最终揭示仿生固态纳米孔单分子检测性能调控机制，为仿生固态纳米孔器件的优化简化设计提供理论基础。

本项目组通过理论建模和大规模计算模拟等手段系统研究了生物及仿生纳米孔内受限分子的动力学行为及其传输特性。首先研究了多种典型生物纳米孔的静电势分布和离子电流阻塞规律，揭示了部分纳米孔的优异检测性能背后的物理力学机制。以此为基础，构筑了由氮化硅和石墨烯纳米孔堆叠而成的仿生固体纳米孔，研究了外加偏压驱动下仿生固态纳米孔内待测分子的传输动力学，揭示了待测分子引起的离子电流阻塞信号幅值、持续时间与仿生纳米孔形状之间的关联规律。此外，我们还研究了针尖-基底缝隙等其他类型纳米孔道内分子、离子的新颖动力学行为。通过本项目研究，发展了针对仿生固态纳米孔的建模方法和模拟技术；认识了纳米孔表面形貌、带电性等特征对单分子检测性能的影响规律；提出了具有优良单分子检测性能的仿生固态纳米孔器件原型。本项目成果不仅深化了对纳米孔内受限分子传输动力学的认识，也可为纳米孔器件设计和优化提供理论指导。在本项目的支持下，已在Advanced Materials、Nanoscale、Carbon、《科学通报》等著名刊物上发表论文13篇。