College of Biosystems Engineering and Food Science, Key Laboratory of Intelligent Equipment and Robotics for Agriculture of Zhejiang Province, Zhejiang University, Hangzhou 310058, China.
Scion, 49 Sala Street, Rotorua 3010, New Zealand.
ACS Appl Mater Interfaces. 2023 Jun 7;15(22):27034-27045. doi: 10.1021/acsami.3c01094. Epub 2023 May 26.
Ionic current measurement has been the dominant signaling strategy in nanochannel-based sensors. However, the direct probing of the capture of small molecules is still challenging, and the sensing potential of the outer surface of nanochannels is always ignored. Here, we report the fabrication of an integrated nanochannel electrode (INCE) with nanoporous gold layers modified on two sides of nanochannels, and its application for small-molecule analysis was explored. Metal-organic frameworks (MOFs) were decorated inside and outside of nanochannels, enabling the reduction of pore size to several nanometers, which is among the thickness range of the electric double layer for confined ion diffusion. Combined with excellent adsorption characteristics of MOFs, the developed nanochannel sensor successfully constructed the internal nanoconfined space that could directly capture small molecules and instantly generate a current signal. The contribution of the outer surface and the internal nanoconfined space to diffusion suppression to electrochemical probes was investigated. We found that the constructed nanoelectrochemical cell was sensitive in both the inner channel and the outer surface, signifying a novel sensing mode with integration of the internal nanoconfined space and the outer surface of nanochannels. The MOF/INCE sensor showed excellent performance toward tetracycline (TC) with a detection limit of 0.1 ng·mL. Subsequently, sensitive and quantitative detection of TC down to 0.5 μg·kg was achieved in actual chicken samples. This work may open up a new model of nanoelectrochemistry and provide an alternative solution in the field of nanopore analysis for small molecules.
离子电流测量一直是基于纳米通道传感器的主要信号策略。然而，直接探测小分子的捕获仍然具有挑战性，并且纳米通道外表面的传感潜力总是被忽略。在这里，我们报告了一种集成纳米通道电极（INCE）的制造，该电极在纳米通道的两侧修饰有纳米多孔金层，并探索了其在小分子分析中的应用。金属有机骨架（MOFs）被修饰在纳米通道内外，将孔径缩小到几个纳米，这在受限离子扩散的双电层厚度范围内。结合 MOFs 的优异吸附特性，开发的纳米通道传感器成功构建了可以直接捕获小分子并立即产生电流信号的内部纳米受限空间。研究了外表面和内部纳米受限空间对扩散抑制对电化学探针的贡献。我们发现，构建的纳米电化学池在内部通道和外表面都很敏感，这标志着一种具有内部纳米受限空间和纳米通道外表面集成的新型传感模式。MOF/INCE 传感器对四环素（TC）表现出优异的性能，检测限为 0.1ng·mL。随后，在实际的鸡样品中实现了对 TC 的敏感和定量检测，检测限低至 0.5μg·kg。这项工作可能开创了纳米电化学的新模式，并为小分子的纳米孔分析领域提供了一种替代解决方案。
