Department of Biological and Chemical Sciences, Illinois Institute of Technology , Chicago, Illinois 60616, United States.
Acc Chem Res. 2013 Dec 17;46(12):2867-77. doi: 10.1021/ar400031x. Epub 2013 Apr 24.
Nanopore sensors have emerged as a label-free and amplification-free technique for measuring single molecules. First proposed in the mid-1990s, nanopore detection takes advantage of the ionic current modulations produced by the passage of target analytes through a single nanopore at a fixed applied potential. Over the last 15 years, these nanoscale pores have been used to sequence DNA, to study covalent and non-covalent bonding interactions, to investigate biomolecular folding and unfolding, and for other applications. A major issue in the application of nanopore sensors is the rapid transport of target analyte molecules through the nanopore. Current recording techniques do not always accurately detect these rapid events. Therefore, researchers have looked for methods that slow molecular and ionic transport. Thus far, several strategies can improve the resolution and sensitivity of nanopore sensors including variation of the experimental conditions, use of a host compound, and modification of the analyte molecule and the nanopore sensor. In this Account, we highlight our recent research efforts that have focused on applications of nanopore sensors including the differentiation of chiral molecules, the study of enzyme kinetics, and the determination of sample purity and composition. Then we summarize our efforts to regulate molecular transport. We show that the introduction of various surface functional groups such as hydrophobic, aromatic, positively charged, and negatively charged residues in the nanopore interior, an increase in the ionic strength of the electrolyte solution, and the use of ionic liquid solutions as the electrolyte instead of inorganic salts may improve the resolution and sensitivity of nanopore stochastic sensors. Our experiments also demonstrate that the introduction of multiple functional groups into a single nanopore and the development of a pattern-recognition nanopore sensor array could further enhance sensor resolution. Although we have demonstrated the feasibility of nanopore sensors for various applications, challenges remain before nanopore sensing is deployed for routine use in applications such as medical diagnosis, homeland security, pharmaceutical screening, and environmental monitoring.
纳米孔传感器作为一种无需标记和无需放大的技术，已被用于测量单分子。该技术于 20 世纪 90 年代中期首次提出，其利用在固定施加电势下，目标分析物通过单个纳米孔时产生的离子电流调制来进行检测。在过去的 15 年中，这些纳米级孔已被用于 DNA 测序、研究共价和非共价键相互作用、研究生物分子的折叠和展开，以及其他应用。纳米孔传感器应用中的一个主要问题是目标分析物分子快速通过纳米孔。当前的记录技术并不总是能准确检测到这些快速事件。因此，研究人员一直在寻找能减缓分子和离子传输的方法。到目前为止，几种策略可以提高纳米孔传感器的分辨率和灵敏度，包括改变实验条件、使用主体化合物以及修饰分析物分子和纳米孔传感器。在本报告中，我们重点介绍了我们最近的研究工作，这些工作集中在纳米孔传感器的应用上，包括手性分子的区分、酶动力学的研究以及样品纯度和组成的测定。然后，我们总结了我们在调节分子传输方面的努力。我们表明，在纳米孔内部引入各种表面功能基团，如疏水性、芳香性、正电荷和负电荷残基，增加电解质溶液的离子强度，以及使用离子液体溶液作为电解质而不是无机盐，都可能提高纳米孔随机传感器的分辨率和灵敏度。我们的实验还表明，在单个纳米孔中引入多个功能基团和开发模式识别纳米孔传感器阵列，可以进一步提高传感器的分辨率。尽管我们已经证明了纳米孔传感器在各种应用中的可行性，但在医疗诊断、国土安全、药物筛选和环境监测等应用中常规使用纳米孔传感技术仍存在挑战。
