The Estimation of Field-Dependent Conductance Change of Nanopore by Field-Induced Charge in the Trans locations of AuNPs-DNA Conjugates

Solid-state nanopores have been proven to be a powerful tool for the characterization of individual molecules and nanoparticles. The basic motivation of this technique is to determine the particle size by the conductance change during the translocation of the particle. However, there still has not been a quantitative estimation of the dependence of electric field on the conductance change due to a particle translocation. Here, we present the first observations of the intriguing biphasic and asymmetrical events in the translocations of DNA-modified gold nanoparticles through similar to 60 nm nanopores. An electric field-dependent conductance change and quadratic nonlinear electrophoresis were observed as well. Thus, we develop an approximation of the conductance change of nanopore based on induced-charge electrophoresis. The effects of salt concentration, the applied voltage, and particle radius on the conductance change are studied. This study gives a fundamental understanding and provides valuable suggestions to understand the translocation of biomolecular attached metal nanoparticles through nanopores. The results indicate a novel way for direct observation and study of nonlinear electrophoresis of single nanoparticles using nanopore technique as well.