Fabrication of electrochemical DNA biosensor based on electrostatic interactions

There is a growing need for rapid and accurate detection of contaminants in various sample materials for clinical, environmental and industrial analyses. This thesis has used Escherichia coli DNA as a model DNA to develop new the DNA biosensors based on electrostatic interactions. In electrostatic repulsion of [α-SiW₁₂O₄₀]^4- anions with the anionic phosphate backbone of DNA is proposed. Whereas, in electrostatic attraction of [Ru (NH₃)₆]³⁺ cations with the anionic phosphate backbone of DNA is proposed. The detection of DNA hybridization was successfully accomplished by Fourier transformed alternating current voltammetry (FTACV) and differential pulse voltammetry (DPV). Further improvement in performance was accomplished by use of two nanocomposite materials, gold-multiwalled carbon nanotubes (Au-MWCNTs) and gold-reduced graphene oxide (Au-RGO).