Bottom-up surface engineering of DNA macro-assemblies for nanoelectronics and optical biosensors
Gnanaprakasa, Tony Jefferson
Type of Degreethesis
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Nanotechnology has promised an out of the ordinary impact on mankind. From the most mundane of consumables to the indispensable advancements in health care and medicine that it has potential in; make it an exciting revolution in science and engineering. Design and implementation of nanomaterials for the applications mentioned afore is the next big challenge. Despite the prodigious efforts carried out in unraveling the complications encountered, it is still problematical to engineer nanomaterials because of their physiochemical properties that make them complex systems to manifest, yet enthralling to work with. Standing out from this category of fascinating materials, single-walled carbon nanotubes (SWNTs) have been of great interest for their outstanding physical and chemical properties and their potential in the future of nanoelectronics and nanomedicine. In recent years, three dimensional nanoarchitectures have been found to be the apt candidates for the development of nanoelectronic devices and novel sonde diagnostic platforms. But lack of the proper chemical functionalities and biocompatibility has impeded their impact on nanomedicine and clinical diagnostics. Deoxyribonucleic acid (DNA) is a bio-nanomaterial from nature‟s tool box and forms the central icon of modern medicine and has been greatly admired for its versatility and complex design. As a result, DNA was used as a template to design a layer-by-layer assembled SWNT based macromolecular surfaces for nanoelectronics with great control. These 3D nanoarchitectures provide a promising step in developing novel biomimetic antimicrobial thin films. The electron transfer properties and conductivity of these materials was then studied using scanning electrochemical microscopy (SECM) as a non-destructive method. It was verified that the charge injection through the multilayers were solely due to electron hoping across the DNA-SWNT adducts, as a result of an increase in feedback response from the SECM. Subsequently, portable and sensitive optical biosensors were designed for the detection of the virulent disease causing gene in foodborne pathogens. In this case, the virulent hipO gene from Campylobacter jejuni was detected using a DNA self-assembled monolayer developed over gold surface on a surface plasmon resonance (SPREETA) platform and avidinated polystyrene surface on the diffraction optics technology (DOT) platform in real-time with high specificity. Hence the research presented here elaborates the use of DNA as a molecular tool to develop novel biomimetic nanoelectronic and medical diagnostic sensor platforms.