Detection and discrimination of nanoparticles using bullet shape nanopores coated with PEG

Abstract

The use of single track-etched nanopores to distinguish molecules is limited by the difficulty in comparing independent experiments. This is mainly because the properties (size, surface state) among various equivalent nanopores are not strictly identical. In this work, we propose a way to discriminate different sized gold nanoparticles coated with PEG from 38 to 90 nm using bullet-like shape nanopores with tip diameters of 100 and 130 ± 30 nm, functionalized with polyethylene glycol (PEG) chains of different lengths (5 and 20 kDa). We show that the two classical parameters of current perturbations (the relative blockade amplitude and the dwell time) caused by the interaction of the nanoparticles with the nanopore allow the discrimination of the nanoparticles using each nanopore independently. Indeed, both the nanopore diameter and the PEG length influence the current blockade parameter, showing that it is possible to distinguish nanoparticles from independent experiments despite the inherent variability of the track-etched nanopores.