Measurement of Ion Selectivity

Creative Bioarray is committed to providing clients with experimental measurement services for ion channel selectivity using a variety of methods, which helps them understand important knowledge about ion permeation and selectivity. Our dedicated research team and the wide range of advanced technologies available guarantee to meet your scientific research needs.

Background

Ion channels form action potentials and gradient potentials on the cell membrane, which determine the excitability and conductivity of cells. Except that some ion channels can pass through several ions non-selectively, most ion channels have selective permeability to different ions. Such precise control of ionic current regulated by protein ion channels is the basis for the proper functioning of the cells. Studying the mechanism of ion permeation and selectivity in ion channels is the key to understanding the function of ion channels correctly.

The application of advanced experimental and theoretical methods, especially electrophysiological measurement, structural analysis, and kinetic simulation, has gained a lot of knowledge about ion permeation and selectivity in the past two decades. The development of these technologies has provided the possibility for the inspection of the mechanisms of ion transport through ion channels at macroscopic and microscopic levels of resolution and, in many cases, in a time-resolved picture.

Fig. 1 Cell membranes contain channels that selectively permit ions to move into or out of the cell. (Mita, 2021)

Measurement of Ion Channel Selectivity

We provide measurement services for our clients through multiple methods, including:

• Measurement of ion selectivity through the ratio of ionic conductance, the reversal potential for currents under biionic conditions, crystallographic titration, or through channel block experiments.
• Computationally estimation of ion channel selectivity through the ratio of ion conductance, free-energy perturbation, or by comparing the potential of mean force (PMF) for the permeation of different ion species.
• Calculation of selectivity by combining ion binding affinity and permeation rates in a PMF or free energy profile of ion permeation.

Based on the above strategies, we provide measurement services for clients, including but not limited to:

• Measurement of ion selectivity of potassium channels, sodium channels, and calcium channels.
• Quantification and interpretation of ion selectivity in wide channels, such as the OmpF porin of the outer membrane of E. coli.

Applications

• Study on the molecular mechanism of ion channels transporting ions across cell membranes in a selective manner
• Study on the physical mechanisms leading to ion permeation
• Establishment of accurate models to simulate ion permeation and selectivity

Creative Bioarray has a first-class comprehensive technology platform and has accumulated a lot of experience in ion channel detection. Our research team has established a variety of experimental measurement protocols to provide clients with flexible solutions. If you are interested in our service, please feel free to contact us and we will provide you with reliable measurement results in a short period.

Reference

1. Mita, K.; et al. Conductance selectivity of Na⁺ across the K⁺ channel via Na⁺ trapped in a tortuous trajectory. Proceedings of the National Academy of Sciences, 2021, 118(12): e2017168118.