EPFL BioE Talks SERIES "Nanofluidics Beyond Single Nanopores and Aqueous Media"


Event details

Date 27.02.2023
Hour 16:0017:00
Speaker Prof. Zuzanna S. Siwy, University of California, Irvine, CA (USA)
Location Online
Category Conferences - Seminars
Event Language English

Single nanopore research has revolutionized many areas, from DNA/protein sequencing to molecular separations. Inspired by Nature, we propose to move beyond the confines of single nanopores and create programmable arrays of interacting nanopores. If we could create an array of nanopores embedded in the same membrane where transport through individual nanopores depends on the presence and properties of neighboring nanopores, we could create highly intricate ionic systems with tunable and responsive transport properties. I will describe our first results on ionic transport through nanopore arrays consisting of three up to nine nanopores located at tunable positions and interpore distances. The nanopores interact with each other via overlapping depletion zones at pore entrances created by concentration polarization. The interactions can be further tuned by salt concentration and modifying the chemistry of the pore walls such that each pore functions as a diode. Interactions of such nonlinear ionic devices leads to unusual additivity of conductances of individual pores. Finally, I will discuss possibilities to induce different transport properties in pores in the same array by placement of gate electrode.
The majority of nanopore experiments and modeling has considered aqueous environment. In the second part of the talk, I will discuss new transport properties of nanopores that originate from a choice of solvent. By replacing water with aprotic, high dipole-moment organic solvents, we have achieved unusual interfaces where the distributions of potential and ions are dictated by the long-range bilayer structure of the solvent. Using acetonitrile as an example solvent and silica an example surface, we show that the solid/liquid interface exhibits effective surface potential whose sign switches from negative in low salt concentrations to positive at higher salt concentrations. The threshold concentration at which the surface potential changes sign is dependent on the chemical identity of the salt as well as sizes of the constituent ions. Acetonitrile and other high dipole moment aprotic solvents can therefore create interfaces whose molecular structure influence macroscopic observables such as ion current.

Dr. Zuzanna S. Siwy received her Ph.D. in 1997 from the Silesian University of Technology, Gliwice, Poland, and habilitation in 2004. She was a Fellow of the Foundation for Polish Science, and the Alexander von Humboldt Foundation at the Institute for Heavy Ions Research (GSI) in Darmstadt, Germany. In 2005, Dr. Siwy joined the Department of Physics and Astronomy at the University of California, Irvine. In 2007, she became the Fellow of the Alfred von Sloan Foundation. In 2009, Dr. Siwy was awarded the Presidential Early Career Award for Scientists and Engineers as well as the Bessel Award from the Alexander von Humboldt Foundation. She is a Fellow of the American Physical Society, and AAAS. Her current research interests focus on using synthetic nanopores as templates for biomimetic channels, preparation of ionic diodes and ionic transistors as well as model systems to discover new physics under nanoconfinement.

Zoom link (with one-time registration for the whole series) for attending remotely: https://go.epfl.ch/EPFLBioETalks

Practical information

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Nanofluidics - Nanopores