Date of Award

Summer 2014

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Electrical & Computer Engineering

Committee Director

Ravindra P. Joshi

Committee Member

Linda L. Vahala

Committee Member

Frederic D. McKenzie

Committee Member

Shu Xiao

Abstract

This dissertation focuses on the dynamics and bioeffects of electroporation of biological cell and ionic conduction in nanopores under high-intensity, nanosecond pulses. The electroporation model utilized the current continuity equation and the asymptotic Smoluchowski equation to explore the transmembrane potential and pore density of the plasma and intracellular membranes; the ionic conduction model employed the Poisson-Nernst-Planck equations and the Navier-Stokes equations to analyze the ionic current and ion concentration profile.

Nanosecond electric pulses of high-intensity amplitude can initiate electroporation of intracellular organelles. The pulse parameters and cell electrical properties, that can selectively electroporate liposomes but keep the plasma and nuclear membranes intact, have been evaluated and optimized. This opens up the possibility of loading cell liposomes with potent drugs for subsequent release as part of a procedure for electrochemotherapy.

The traditional spherical model ignores the geometric influence; therefore, the more realistic irregular shape of intracellular organelles is considered to explore the geometric impact on dynamics of electroporation. The results obtained here show that in the shorter pulse range, geometric dependence is very pronounced, and so short pulses could be very effective in highly irregularly shaped cells.

In addition, nanopore transport is analyzed using a numerical method that couples the Nernst-Planck equations for ionic concentrations, the Poisson equation for the electric potential and Navier-Stokes equations for the fluid flow. Roles of the applied bias, the geometric asymmetry in the nanopore, as well as the charge distribution lining the membrane are comprehensively examined. The results show non-linear I-V characteristics that are in reasonable agreement with data, and suggest a bias-dependent expansion of an asymmetric pore, possibly arising from the enhanced flux of incident ions on the membrane walls.

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DOI

10.25777/y7jm-my45

ISBN

9781321316568

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