Nanoparticle Transport in Conical-Shaped Nanopores

Abstract

This report presents a fundamental study of nanoparticle transport phenomena in conical-shaped pores contained within glass membranes. The electrophoretic translocation of charged polystyrene (PS) nanoparticles (80- and 160-nm-radius) was investigated using the Coulter counter principle (or "resistive-pulse" method) in which the time-dependent nanopore current is recorded as the nanoparticle is driven across the membrane. Particle translocation through the conical-shaped nanopore results in a direction-dependent and asymmetric triangular-shaped resistive pulse. Because the sensing zone of conical-shaped nanopores is localized at the orifice, the translocation of nanoparticles through this zone is very rapid, resulting in pulse widths of ~200 μs for the nanopores used in this study. A linear dependence between translocation rate and nanoparticle concentration was observed from 10(7) to 10(11) particles/mL for both 80- and 160-nm-radius particles, and the magnitude of the resistive pulse scaled approximately in proportion to the particle volume. A finite-element simulation based on continuum theory to compute ion fluxes was combined with a dynamic electric force-based nanoparticle trajectory calculation to compute the position- and time-dependent nanoparticle velocity as the nanoparticle translocates through the conical-shaped nanopore. The computational results were used to compute the resistive pulse current-time response for conical-shaped pores, allowing comparison between experimental and simulated pulse heights and translocation times. The simulation and experimental results indicate that nanoparticle size can be differentiated based on pulse height, and to a lesser extent based on translocation time.

Protein detection using tunable pores: resistive pulses and current rectification

“…These channel have applications in biosensing [4][5][6] , materials characterisation 7,8 , quantification of ligandtarget interactions [9][10][11] , drug delivery 12 , and mimicking biological systems enabling, the study of ionic transport within confined geometries [13][14][15][16] . These nanopores have been created in a range of materials from graphene [17][18][19][20] , polymers 21 , silicon nitride 22 and glass 13,14,23,24 .…”

Biphasic Resistive Pulses and Ion Concentration Modulation during Particle Translocation through Cylindrical Nanopores

“…The modeling method is similar to that in ref 33, while we show a more detailed discussion on the resistive pulses with cylindrical nanopores, considering the combined effects of electrolyte concentration, surface charge, electric potential and pore geometry. Since the transition from current-position curves to current−time curves did not change the current magnitude on the vertical axis, 20 we obtained the current-position curve as a reflection of the recorded signal in time. The direction of translocation is determined by the surface charge and electric field.…”

Rapid Ultrasensitive Single Particle Surface-Enhanced Raman Spectroscopy Using Metallic Nanopores

“…As will be shown nanopores can be used to facilitate the rapid detection of single NPs while still collecting full vibrationally rich spectral information of the analyte. Importantly, NP translocation events, of both metallic and non-metallic particles, using SiN x solid-state nanopores have already been documented albeit by characterizing the translocation events using electrical means using a high ionic strength solution 29,30,31 . Generally speaking such a high ionic strength would typically aggregate larger unprotected Au NPs.…”