Nanometer-scale pores have demonstrated potential as a tool for the electrical detection and characterization of molecules. To provide a physical basis for nanopore-based analytical metrology, we show that a simple model quantitatively describes how one type of analyte (polymers of poly(ethylene glycol), PEG) reduces the ionic current in a single α-hemolysin ion channel. Two critical observations are apparent in the data. The depth of PEG-induced current blockades and the residence time of the polymer in the nanopore both decrease with increasing applied potential. A model is presented which describes these phenomena by analyzing the polymer size, and cation interactions with the polymer under moderate confinement.
Citation: Proceedings of the National Academy of Sciences of the United States of America
Pub Type: Journals
bioelectronics, nanopore sensing, single molecule analysis