Effect of concentration gradient on ionic current rectification in polyethyleneimine modified glass nano-pipettes

Abstract

Ion current rectification dependent on the concentration gradient of KCl solutions was systematically investigated in polyethyleneimine modified glass nano-pipettes with inner diameter of 105 nm. Peak shape dependence of the rectification factor on outer KCl solution concentration was observed when inner KCl solution with concentration from 1 mM to 500 mM was used. The peak shape dependence was also observed when the concentrations of the inner and outer KCl solutions were identically controlled. The peak shape in the ion current rectification could be explained by the ion conductance changes through the conical nano-pipette, which result from modulation of ion concentration.

Recent advances of DNA sequencing via nanopore-based technologies

“…Yet, the system still suffers from some intrinsic limitations, such as vulnerability to external perturbations including pH, temperature, and mechanical vibration. These drawbacks could be readily overcome in solid-state nanopores, which are usually made from durable inorganic and polymeric materials like silicon [13], silicon nitride [14], and polyethylenimine [34]. In Zhang et al [35] discovered that substituting the electrolyte solution of KCl with MgCl 2 could slow down the DNA mobility by three times, owing to the reduced charge density on the DNA backbone derived from Mg 2?…”

Argon gas flow through glass nanopipette

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“…Now, in order to determine the constants 12 , aaand d , the following transformed conditions (13) -(14) should be applied on relation (26) according to:…”