Modeling of the Electrical Conductivity of DNA

The authors have developed a PSpice model of the electrical behavior of DNA molecules for use in nanoelectronic circuit design. To describe the relationship between the current through DNA and the applied voltage we used published results of the direct measurements of electrical conduction through DNA molecules. The experimental dc current-voltage (-) curves show a nonlinear conduction mechanism as well as the existence of a temperature dependent semiconductive voltage gap. A weighted least-squares polynomial fit to the experimental data at one temperature, with fitted temperature dependent polynomial coefficient of the linear term, was used as a mathematical model of electrical behavior of DNA. An equivalent electrical circuit was created in PSpice in which DNA was modeled as a voltage-controlled current source described by the mathematical model that includes temperature dependence . PSpice simulations with this model generated - curves at other temperatures that were in excellent agreement with the corresponding experimental data (average deviation 5%). This is important because having models of DNA molecules in the form of equivalent electronic circuits would be useful in the design of nanoelectronic circuits and devices.