Department of Chemistry and Biochemistry, Queens College, City University of New York , Flushing, New York 11367, United States.
J Am Chem Soc. 2017 Aug 30;139(34):11654-11657. doi: 10.1021/jacs.7b05058. Epub 2017 Aug 22.
Coating the inner wall of a quartz nanopipet with a thin layer of carbon yields a nanopore with tunable surface charge and chemical state for resistive-pulse and rectification sensing. Herein we report the experimental study and modeling of the electron-transfer gated ion transport processes in carbon nanopipets. The potential of the unbiased carbon layer can be tuned by adding very low (sub-nM) concentrations of redox species to the solution via bipolar electrochemistry. The potential of the carbon layer determines the electrical double-layer structure that, in turn, affects the ionic transport processes. The ion current rectification decreased when redox species with a relatively positive formal potential (e.g., Fe(CN)) were added to the solution and increased upon adding redox species with a negative formal potential (e.g., Ru(NH)). Additionally, the ion current displays high sensitivity to redox species, suggesting the possibility of trace-level analysis.
在石英纳米管的内壁涂上一层薄薄的碳，就可以得到一个带有可调表面电荷和化学状态的纳米孔，用于电阻脉冲和整流传感。本文报道了碳纳米管中电子转移门控离子输运过程的实验研究和建模。通过双极电化学，在溶液中添加非常低（亚纳摩尔）浓度的氧化还原物质，可以调谐无偏压碳层的电势。碳层的电势决定了双电层结构，进而影响离子输运过程。当向溶液中添加具有相对正形式电势（例如 Fe(CN)）的氧化还原物质时，离子电流整流减小，而当添加具有负形式电势（例如 Ru(NH)）的氧化还原物质时，离子电流整流增加。此外，离子电流对氧化还原物质表现出高灵敏度，这表明有可能进行痕量分析。
