Evaluation of FEM Electric Field Analysis Using the Electric Properties of Giant Unilamellar Vesicles (GUV) and Jurkat Cells Measured by Electrorotation Spectroscopy: Introduction of Cryo-and Lyoprotectants by Electrofusion of GUVs and Living Cells

摘要

Electrofusion of giant unilamellar vesicles (GUVs) and living cells is a gentle method for delivering membrane impermeable cryo-/lyo-protective molecules into living cells for cryo-/lyopreservation. In this method, an optimal length and strength of an electric pulse are required to initiate GUV-cell fusion. Calculating the electric field by the finite element method (FEM) might be a powerful analytical method for prediction of the optimal pulse length and strength of a deformed and adhered GUV-cell. The objective of this study is to clarify whether an FEM model of a pulsed GUV or cell could be applicable for prediction of its electric field, especially the change of membrane potential. First, electric properties of GUVs and Jurkat cells were derived from electrorotation spectra with a dipole approximation model. Secondly, the electric field and the membrane potential of a single GUV or cell after applying a stepwise electric field were calculated by an FEM model using the measured electric properties. At the first stage after applying a step electric field, the calculated membrane potential by the FEM model shows good agreement with the membrane potential derived from the dipole approximation model. After complete relaxation of the electric field, the calculated membrane potential of the FEM model is lower than that of the dipole approximation model. This might be because both models do not take into account the effects of electric double layers on both sides of the membrane.