Transport time-independent determination of the surface charge of individual nanoparticles using the resistive pulse sensing

We explore the potential application of resistive pulse sensing technology for transport time-independent determining the size and surface charge density of individual nanoparticles simultaneously. The translocation of both uncharged and charged nanoparticles through a nanopore was modeled using the finite element simulation. A positive peak appears when a charged, but not uncharged, nanoparticle exits the nanopore. The magnitude of positive peak depends on the surface charge density and size of the nanoparticle. The formation of the positive peak is presumably attributed to the local ionic polarization induced by the combination of the charged surface and the externally applied electrical field.