Effect Of Electric Field On Cell Deformation And Ion Trans-membrane Migration

The biological effects of electromagnetic field can be divided into thermal effects and non-thermal effects.At the cellular level,non-thermal effects include cell deformation,fusion,rotation,and ion trans-membrane migration,etc.which will affect directly the physiological and biochemical functions of organisms.In this thesis,the effects of external electric field on cell deformation and ion trans-membrane migration have been studied.The results can be used as the basic theory of non-thermal biological effect mechanism of electromagnetic field,and it can also provide valuable guidance for the application of electromagnetic field in biomedical field.The main work is as follows:1.Study on the effect of electric field on the deformation of isotropic single cell.Based on the single spherical shell cell model,the effects of cell membrane dielectric constant,conductivity,cell membrane thickness and external field frequency on cell deformation are numerically analyzed through the change of cell relative elongation modulus without medium consumption;Considering the dispersion of cellular medium,the effect of cell parameters on dielectrophoresis factor was numerically analyzed by using Clausius Mossotti factor.The results show that: When the loss of medium is not considered,the dielectric constant,thickness and external field frequency of cell membrane are the main factors causing cell deformation;Considering the dielectric dispersion,when the external field frequency is less than the constant force frequency range,the cell size is the main factor affecting the dielectrophoresis force.When the external field frequency is greater than the constant force frequency range,the dielectrophoresis force is mainly affected by the dielectric constant of extracellular fluid and the conductivity of internal fluid,and the low-frequency electric field is more likely to cause the biological effect of cells.2.Study on the effect of electric field on the surface electric field stress of anisotropic single cell.Considering the electrical anisotropy of cell membrane,taking a single cell as the research object,the effects of cell membrane normal dielectric constant and applied electric field frequency on cell deformation are numerically analyzed by Maxwell stress tensor method.The results show that: The normal dielectric constant of the membrane has different effects on the electric field stress at different positions on the cell membrane.At the same position,the greater the normal dielectric constant,the greater the normal component of the electric field intensity acting on the cell,and the greater the tangential stress.When the frequency is low,the frequency hardly affects the electric field stress acting on the cell.Within a certain frequency range,the frequency affects the size and direction of the electric field stress acting on the cell.There is a frequency window phenomenon in the electric field stress and cell deformation.3.Analysis of the interaction between electric field and multiple isotropic spherical cells.The spatial electric field line,electric field distribution cloud map and cell surface force density distribution under different spacing and arrangement of cells are obtained by ANSYS Maxwell software.Using Maxwell stress tensor method,the effects of spacing and arrangement on electric field stress distribution are numerically analyzed.The results show that: The number,spacing and arrangement of cells will affect the distribution of electric field stress on the cell surface,and the deformation of cells under the action of electric field is related to the electric field stress on the cell surface.4.Study on the effect of electric field on ion trans-membrane migration.For cells composed of lossless media,the effects of variable electric field on cell trans-membrane potential are analyzed by using bio-electromagnetic theory,and using Nernst and Boltzmann formulas,the effects of external electric field frequency and cell parameters on the relative change of ion concentration on one side of cell membrane are numerically analyzed.The results show that: The geometric and electrical parameters of cells and the frequency of applied electric field affect the changes of trans-membrane potential and ion concentration on one side of cell membrane.For a certain cell,there is a frequency window phenomenon in the changes of trans-membrane potential and ion concentration on one side of cell membrane.