期刊
ACS NANO
卷 9, 期 2, 页码 1117-1126出版社
AMER CHEMICAL SOC
DOI: 10.1021/nn5039433
关键词
nanopore; DNA nanotechnology; nanofluidics; PEG; single-molecule; bilayer membrane
类别
资金
- Leverhulme Trust [RPG-170]
- UCL Chemistry
- EPSRC (Institutional Sponsorship Award)
- National Physical Laboratory
- Oxford Nanopore Technologies
- Winton Program of Physics for Sustainability, Gates Cambridge
- Oppenheimer Trust
- ERC [261101]
- European Research Council (ERC) [261101] Funding Source: European Research Council (ERC)
Membrane-spanning nanopores from folded DNA are a recent example of biomimetic man-made nanostructures that can open up applications in biosensing, drug delivery, and nanofluidics. In this report, we generate a DNA nanopore based on the archetypal six-helix-bundle architecture and systematically characterize it via single-channel current recordings to address several fundamental scientific questions in this emerging field. We establish that the DNA pores exhibit two voltage-dependent conductance states. Low transmembrane voltages favor a stable high-conductance level, which corresponds to an unobstructed DNA pore. The expected inner width of the open channel is confirmed by measuring the conductance change as a function of poly(ethylene glycol) (PEG) size, whereby smaller PEGs are assumed to enter the pore. PEG sizing also clarifies that the main ion-conducting path runs through the membrane-spanning channel lumen as opposed to any proposed gap between the outer pore wall and the lipid bilayer. At higher voltages, the channel shows a main low-conductance state probably caused by electric-field-induced changes of the DNA pore in its conformation or orientation. This voltage-dependent switching between the open and closed states is observed with planar lipid bilayers as well as bilayers mounted on glass nanopipettes. These findings settle a discrepancy between two previously published conductances. By systematically exploring a large space of parameters and answering key questions, our report supports the development of DNA nanopores for nanobiotechnology.
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