Terahertz Electric Field-Induced Membrane Electroporation by Molecular Dynamics Simulations

In this paper, the membrane electroporation induced by the terahertz electric field is simulated by means of the molecular dynamics method. The influences of the waveform and frequency of the applied terahertz electric field on the electroporation and the unique features of the process of the electroporation with the applied terahertz electric field are given. It shows that whether the electroporation can happen depends on the waveform of the applied terahertz electric field when the magnitude is not large enough. No pore appears if the terahertz electric field direction periodically reverses, and dipole moments of the interfacial water and the bulk water keep reversing. The nm-scale single pore forms with the applied terahertz trapezoidal electric field. It is found that the average pore formation time is strongly influenced by the terahertz electric field frequency. An abnormal variation region that shows decline exists on the correlation curve of the average pore formation time and the trapezoidal electric field frequency, whereas the overall trend of the curve is increasing. The decrease of the water oriented polarization degree results in the increase of the electroporation time, and the abnormal variation region appearance may be related to the drastic change of average water hydrogen bond number that is resulted from the resonance of water hydrogen bond network and the applied electric field. Compared to the nanosecond electric pulse and constant electric field, the numbers of the water protrusions and the water bridges are smaller and the pore formation time is relatively longer with the applied terahertz electric field.