Prospects of Observing Ionic Coulomb Blockade in Artificial Ion Confinements

Nanofluidics encompasses a wide range of advanced approaches to study charge and mass transport at the nanoscale. Modern technologies allow us to develop and improve artificial nanofluidic platforms that confine ions in a way similar to single-ion channels in living cells. Therefore, nanofluidic platforms show great potential to act as a test field for theoretical models. This review aims to highlight ionic Coulomb blockade (ICB)—an effect that is proposed to be the key player of ion channel selectivity, which is based upon electrostatic exclusion limiting ion transport. Thus, in this perspective, we focus on the most promising approaches that have been reported on the subject. We consider ion confinements of various dimensionalities and highlight the most recent advancements in the field. Furthermore, we concentrate on the most critical obstacles associated with these studies and suggest possible solutions to advance the field further.

Comment on “The size and structure of selected hydrated ions and implications for ion channel selectivity” by Z.-H. Yang, RSC. Adv., 2015, 5, 1213.

Hydration numbers of electrolytes from freezing point depressions plotted versus the entropic contributions for the gaseous cations dissolving in water.

Reply to the ‘Comment on “The size and structure of selected hydrated ions and implications for ion channel selectivity”’ by A. Zavitsas, RSC Adv., 2016, 6, 92771

We believe that in Zavitsas' previous work the assumption of “ideality” on an aqueous solution of an electrolyte conflicts with experimental evidence and the calculation of ion-pair formation equilibrium constants to demonstrate the existence of an ion-pair is artificial.

The size and structure of selected hydrated ions and implications for ion channel selectivity

The structures of hydrated sodium (yellow) and potassium (red) ions.