Ionic Transport in Electrostatic Janus Membranes. An Explicit Solvent Molecular Dynamic Simulation
Joan M Montes de Oca1,2, Johnson Dhanasekaran1,2, Andrés Córdoba1,2
1Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States.
ACS Nano
|March 1, 2022
Summary
Janus pores act as ionic current rectifiers, with efficiency increasing as pores shrink. Molecular simulations reveal water reorientation and ion segregation, leading to a new model where electric leakage controls transport.
Area of Science:
- Nanotechnology
- Physical Chemistry
- Materials Science
Background:
- Janus membranes, featuring two-sided charges, show potential as ionic current rectifiers.
- Ionic current rectification is achieved by creating a current from salinity gradients using pores with opposite charge regions.
- The efficiency of nanoscale Janus pores is inversely related to their diameter.
Purpose of the Study:
- To investigate the molecular mechanisms underlying rectification in Janus nanopores under an applied electric field.
- To understand the structure and dynamics of water and ions within Janus nanopores.
Main Methods:
- Utilizing molecular simulations with explicit water and ions.
- Analyzing the behavior of molecular species in aqueous electrolyte solutions.
- Comparing simulation results with experimental observations on asymmetric membranes.
Main Results:
- Simulation results align with experimental observations for macroscopic properties.
- Identified pronounced local reorientation of water molecules within the pores.
- Observed segregation of ionic species, not predicted by continuum models.
- Developed a new model for ionic current rectification.
Conclusions:
- Electric leakage at the pore entrance is a critical factor controlling net ionic transport in Janus nanopores.
- Molecular simulations provide unprecedented insight into the nanoscale phenomena governing ionic rectification.
- The findings advance the understanding and design of advanced ionic devices.
More Related Videos
09:42Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
9.1K
08:54Vibrational Spectra of a N719-Chromophore/Titania Interface from Empirical-Potential Molecular-Dynamics Simulation, Solvated by a Room Temperature Ionic Liquid
Published on: January 25, 2020
5.7K
Related Concept Videos
01:44The Significance of Membrane Transport
31.4K
The transport of solutes across the cell membrane is essential for metabolic processes, like maintaining cell size and volume, generating the action potential, exchanging nutrients and gases, etc. Membrane transport can be either passive or active. It can be simple diffusion, facilitated, or mediated transport aided by transport proteins such as transporters and channels.
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
31.4K
01:19Membrane Asymmetry Regulating Transporters
5.2K
Enzymes like flippase, floppase, and scramblase transfer phospholipids from one layer to another in the membrane, thereby affecting membrane asymmetry.
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
5.2K
01:24Protein Diffusion in the Membrane
4.7K
Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...
4.7K
01:29Primary Active Transport
11.3K
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they would...
11.3K
01:23Transcellular Transport of Solutes
3.9K
Transcellular transport of solutes is the movement of substances like monosaccharides and amino acids through polarized cells. This transport mechanism is primarily seen in epithelial and endothelial cells aided by membrane transport proteins such as channels and transporters. The tight junctions between these cells confine the membrane proteins to the two sides of the cell. The epithelial cells have distinct apical and basolateral domains. In contrast, the endothelial cells show the luminal...
3.9K
01:17Pore Transport and Ion-Pair Transport
717
Pore transport and ion-pair formation are critical mechanisms for the absorption and distribution of drugs in the body.
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct...
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct...
717