Single cell electroporation using proton beam fabricated biochips

Abstract

Electroporation introduces polar molecules into a host cell through its membrane by giving quick electrical pulses across the cell. For this thesis, the design and fabrication of a novel single cell electroporation biochip by the proton beam writing technique are presented. The biochip features individual mouse neuroblastoma cells positioned in between nickel micro-electrodes. SYTOX® Green nucleic acid stain (S7020) was then successfully incorporated into the cell upon electrical impulses across the electrodes. Green fluorescence is observed when the stain binds with the DNA inside the cell nucleus. The electric field strengths, pulse durations and numbers of pulses have been considered and optimized to achieve a high transfection rate of 82.1% and survival rate of 86.7%. Proton induced high resolution (~100 nm) fluorescence images of these stained electroporated cells on our biochips further proves that the stain has been successfully bound to the DNA. This single cell electroporation system is a promising method for the introduction of a variety of fluorophores, including nanoparticles and quantum dots, into cells with high success rate.