(256p) Tuning Ionic Current Rectification in a Conical Nanopore By Surface Modification of Polyacrylic Acid Brushes

In cell membranes, the ion channels are asymmetrically distributed and possess various biological functions due to the functional groups, such as carboxylic acid, on the channel wall. Moreover, the extracellular and extracellular solution environments, such as pH and salt concentration, in biological cells are typically different, resulting in several unexpected and interesting ion transport phenomena. Inspired by this, the biomimetic, conical nanopores with biomimetic functional groups, polyacrylic acid(PAA) brushes, are prepared through a vapor-based plasma surface modification of a polymer nanopore made of polyurethane, which reveals different charge properties under different solution pHs. Several key factors, including pH, background salt concentration, and pH and salt gradients, on the ionic current rectification (ICR) of the PAA brushes-modified nanopore are investigated. Results show that in addition to pH and background salt concentration, the ICR can be regulated by pH and salt gradients through the nanopore.