Direct, concurrent measurements of the forces and currents affecting DNA in a nanopore with comparable topography.
We report direct, concurrent measurements of the forces and currents associated with the translocation of a single-stranded DNA molecule tethered to the tip of an atomic force microscope (AFM) cantilever through synthetic pores with topagraphies comparable to the DNA. These measurements were performed to gauge the signal available for sequencing and the electric force required to impel a single molecule through synthetic nanopores ranging from 1.0 to 3.5 nm in diameter in silicon nitride membranes 6-10 nm thick. The measurements revealed that a molecule can slide relatively frictionlessly through a pore, but regular fluctuations are observed intermittently in the force (and the current) every 0.35-0.72 nm, which are attributed to individual nucleotides translating through the nanopore in a turnstile-like motion.
University of Notre Dame , Stinson-Remick Hall, Notre Dame Avenue, Notre Dame, Indiana 46556, United States.
Edward M
EM
Nelson
Hui
H
Li
Gregory
G
Timp
D001710:Biotin / Q000737:chemistry; D002138:Calibration; D004247:DNA / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D020342:Finite Element Analysis; D007700:Kinetics; D046210:Microfluidic Analytical Techniques; D044085:Microfluidics; D018625:Microscopy, Atomic Force; D058608:Nanopores; D036103:Nanotechnology / Q000379:methods*; D009690:Nucleic Acid Conformation; D017422:Sequence Analysis, DNA; D017655:Silicon Compounds / Q000737:chemistry; D019809:Streptavidin / Q000737:chemistry
D004277:DNA, Single-Stranded; D004129:Dimethylpolysiloxanes; D017655:Silicon Compounds; C013830:baysilon; D001710:Biotin; D004247:DNA; D019809:Streptavidin; C032734:silicon nitride