BIONANOTRONICS: ON THE MICROFABRICATION OF ELECTRODES FOR THE EXAMINATION INTO THE NATURE OF CURRENT TRANSDUCTION THROUGH DEOXYRIBONUCLEIC ACIDS

Includes bibliographical references (pages 132-137).Maintaining Moore's law has become increasingly difficult. The rate at which integrated circuits are made smaller, faster, and more energy efficient is decelerating. Technical, optical, quantum mechanical, and economic limitations inherently part of using silicon and standard microfabrication techniques such as photolithography are fast approaching their limits on how small the fundamental units of electronics can be. Natural polymers such as deoxyribonucleic acids (DNA) may have the potential to act as charge carrying wires and replace silicon. Being small (2nm width), carbon-based, relatively inexpensive, and having a complex highly reliable self-assembly and self-repair mechanism make DNA a focus for electrical transduction platforms, but its potential to act as a charge carrier is still unknown. Early studies show mixed results having DNA conductivity ranging from that of an insulator to that of a superconductor suggesting that more research is required. The purpose here is to design and manufacture a series of microelectrodes to act as testing platforms to better electrically characterize the conductivity of DNA so that its potential to be used as a fundamental charge carrying unit can be better understood. Microelectrodes designed and manufactured include (A) 2-dimensional gold microelectrodes to reproduce and verify past DNA conductivity studies, (B) 3-dimensional gold microelectrodes to create a suspended DNA bridge minimizing the effect of the substrate, (C) 3-dimensional pyrolyzed SU-8 polymer microelectrodes, a form of glassy carbon, for the study of potential inexpensive biocompatible alternatives to gold-based electrodes, (D) 3-dimensional sub-micron SU-8 nanoelectrodes using electron-beam lithography for current transduction experiments on much smaller lengths of DNA compared to the standard 15??m length of ??-DNA, (E) 3- dimensional PolyFerroCNT??? electrodes comprised of polydimethylsiloxane, ferrofluid, and graphetized multi-walled carbon nanotubes for the purpose of creating thermally stable, flexible, conductive, semi-transparent, and biocompatible electrodes with magnetically inducible ???active??? microstructures. All five types of microelectrodes, with exception of those manufactured using electron-beam lithography, were successfully manufactured and tested for their ability to attach to either synthesized oligonucleotides or ??-DNA