Single-Cell Biophysics: Measurement, Modulation, and Modeling

Single-Cell Biophysics: Measurement, Modulation, and Modeling

Poster Abstracts

19-POS Board 10 Can Microsecond Pulse Affect Endoplasmic Reticulum? Theoretical Proof of Concept with a Realistic Microdosimetry Single-Cell Model Agnese Denzi 1,2 , Hanna Hanna 3 , Frank M. Andre 3 , Lluis M. Mir 3 , Francesca Apollonio 2 , Micaela Liberti 2 . 1 Istituto Italiano di Tecnologia, Rome, Italy, 2 University of Rome “La Sapienza, Rome, Italy, 3 CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gustave Roussy,, Villejuif, France. The use of electric pulses has become a promising application in cancer. Usually, pulses with duration in the range of μs and amplitude of kV/m are used to permeabilize the plasma membrane. Shorter pulses, with duration from few to hundreds of nanoseconds and amplitude of MV/m, are used to also permeabilize the cell internal structures, due to their higher frequency content [1]. Aim of this work is to theoretically demonstrate the efficacy of electroporation with a 100 μs pulse also on endoplasmic reticulum (ER). An accurate 2D microdosimetry model was obtained considering real images from an optical microscope: the nucleus in blue (Hoechst 33342) whereas the ER in green (Fluo-4). A MATLAB®2013 custom algorithm has been developed to recognize cell, ER and nucleus borders. Successively the images have been transformed in vector ones and imported in an electromagnetic simulator. The parameters for the model were taken from [2]. The maximum of the transmembrane potential has been considered both for the plasma and the ER membranes. Considering a poration threshold value as in [3], the external electric fields necessary to obtain the cell (Eth_cell) and ER (Eth_ER) poration have been calculated (Table 1). TABLE I Parameter Values The efficacy of 100 μs pulse in ER poration has been numerically demonstrated and can be related to the higher frequency content present in the rise and fall times of the applied pulse. Furthermore, the electroporation of the external membrane could facilitate the electric field to penetrate inside the cell. [1] M. Breton et al, Bioelectromagnetics, 2012. [2] A. Denzi et al, Journal of membrane biology, 2013. [3] K. C. Smith et al, Plasma Science, IEEE Transactions on, 2006. Eth_cell (MV/m) ≈0.02 Eth_ER (MV/m) ≈0.07 Ratio=Eth_ER/Eth_cell ≈3.5

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