Investigation of biophysical properties of ion channels with nonlinear methods

The aim of this study is to show how nonlinear methods can be used to investigate the biophysical properties of ion channels. For this purpose, the membrane ion current signals of the EAG1 potassium channel of MCF-7 cells and of the TRP channel of ARPE-19 cells were used. Entropy measurements and maximum Lyapunov exponent were chosen as nonlinear methods. The vital state functional of the ion channels in the membrane was monitored using the entropy parameter. The behavioural or functional sensitivity of ion channels was quantified by the maximum Lyapunov exponent. It is known that the entropy of a system increases as it moves towards equilibrium. In this context, during the electrical activity of a living cell, the entropy of the cell reaches its maximum when the membrane ion fluxes reach the equilibrium, that is, when the value of the ion fluxes approaches zero. Therefore, the accuracy of the results obtained in this study was calibrated by reference to this general assumption. The results show functional differences between the MCF-7 EAG1 potassium channel and the ARPE-19 TRP channel. This method has potential applications in analysing cell behaviour or studying ion channel biophysical properties. It can also be used to observe differences in the behaviour of normal and cancerous cells of the same type, or to measure the effects of drugs on the cell.