Probing Ion Channels with Water-Soluble Polymers
Added at the same weight concentration, differently sized polymers reduce bulk solution conductivity to a similar extent. However, their action on the channel conductance is size-dependent. To enter the channel pore, large polymers have to overcome a significant entropic barrier, whereas small polymers are able to penetrate and inhibit ion current through the pore more efficiently. Therefore, the polymer-induced change in channel conductance quantitatively gauges the channel size.
Related references:
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