Ion Concentration Polarization Tunes Interpore Interactions and Transport Properties of Nanopore Arrays

• Published in: Advanced functional materials Vol. 34; no. 11
• Main Authors: Cao, Ethan, Cain, DaVante, Silva, Savannah, Siwy, Zuzanna S.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.03.2024
• Subjects: Arrays; Biological activity; Biological properties; Biomimetics; Cell membranes; Channels; Circuit design; Depletion; Ion concentration; ion concentration polarization; ionic diodes; Modelling; nanopore arrays; Polarization; Silicon nitride; Transport properties
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202312646

Biological processes require concerted function of many channels embedded in the cell membrane. While single solid‐state nanopores are already designed to mimic properties of individual biological channels, it is not yet known how to connect the pores to achieve biomimetic ionic circuits with interacting components. To identify fundamental processes that control interactions between nanopores embedded in the same membrane, a model system of minimal arrays consisting of two and three nanopores in silicon nitride films is designed. The constituent nanopores have an opening diameter <10 nm, and the interpore spacing is tuned between 15 and 200 nm. The experimental and modeling results reveal that nanopores in an array interact with each other via overlapping depletion zones created by the process of concentration polarization. The interactions can be further controlled by salt concentration and voltage. These results showcase a possibility of tuning interactions between nanopores and transport properties of arrays by chemical modification of the pore walls. Arrays consisting of nanoporous ionic diodes feature depletion zones with higher concentrations, and lower current suppression than homogeneously charged pores. These experiments and modeling provide the first steps to leave the constraints of single nanopores and to design biomimetic ionic circuits. All biological processes are based on ionic circuits composed of interacting channels in a cell membrane. Inspired by nature, ionic circuits composed of two and three solid‐state nanopores are designed with tunable interpore distances and diameters. The experiments and modeling identify fundamental physical phenomena that underlie interactions between nanopores and pave the way toward designing biomimetic processes.