Effects of Ultraviolet Light Irradiation on the Electrical Properties of Dna Molecular Wires

OF THE THESIS Effects of Ultraviolet Light Irradiation on the Electrical Properties of DNA Molecular Wires by James Chi Masters of Science in Bioengineering: Biomechanics San Diego State University, 2014 Fabrication process for nanotechnology is approaching the barriers set by the fundamental laws of physics. Alternative technologies for implementing long term molecular wires in electronics such as deoxyribonucleic acids (DNA) continue to be pursued. Specifically, this thesis recorded the electrical properties of double-stranded λ-DNA during exposure of ultraviolet (UV) light. Various researches have confirmed that DNA undergoes a biochemical change when exposed to UV light. Further insight showed that the primarily damages occurred by the creation of cyclobutane pyridimine dimers (CPDs). This will likely induce a change in the electrical conductivity of the system. In this research, DNA is suspended between two 3dimensional microelectrodes, separated by a 10 micron gap, fabricated using negative lithography. Afterwards, separate samples were either exposed to UV-C (254 nm) or UV-B (365 nm) light at 0.6 Joules/cm 2 intervals. Experimental results showed that electrical conductivity decreased dependent on the amount of UV irradiation absorbed by the DNA. Also, UV-C light produced a quicker response than UV-B light. Additionally, oversaturation of UV light energy will eventually cause the DNA wire to dissociate. The nature of molecular charge transport mechanisms in DNA postulates multiple responses from various researchers. However, the specificity of UV light damage on the structure of DNA provided a unique experiment that helped test certain postulations. This thesis will mainly discuss charge hopping and tunneling mechanism and its application after UV light radiation.