The incorporation of valinomycin, a neutral antibiotic, into a polyvinyl chloride membrane allows for the manufacture of an ion-selective electrode that is highly selective for potassium.
<h3>How Valinomycin Ionophores Enter and Transport K+ across Model Lipid Bilayer Membranes?</h3>
A biomimetic lipid membrane attached to the surface of the gold electrode contained the cyclic peptide valinomycin.
The ionophore characteristics of the peptide were investigated using electrochemical impedance spectroscopy, and the conformation and orientation of the antibiotic valinomycin within the membrane were identified using polarization modulation infrared reflection absorption spectroscopy.
By forming a complex with potassium ions and an ion pair with a counter anion, valinomycin transports ions across the membrane, and the combination of these two techniques revealed novel information about the ionophore mechanism.
The ion pair is located inside the hydrophobic portion of the membrane and makes a little angle of around 22° with the surface normal.
