DNA Biosensor for Determination of 5-Fluorouracil based on Gold Electrode Modified with Au and Polyaniline Nanoparticles and FFT Square Wave Voltammetry

Document Type: Research Paper


1 Center of Excellence in Electrochemistry, University of Tehran, Tehran, Iran

2 Medical Faculty, Shahid Beheshti University of Medical Sciences, Tehran, Iran


In the present study, a new biosensor for 5-Fluorouracil was described using modified gold
electrode and Fast Fourier transform square wave voltammetry (FFT SWV). Calf thymus DNA
immobilization was on a gold electrode decorated with polyaniline and gold nanoparticles. The
electrochemical characteristics of the electrodes were investigated by cyclic voltammetry, and
electrochemical impedance spectroscopy. After interaction DNA with the analyte, a dramatic
decline in [Fe(CN)6]/[Fe(CN)6]]3-/4- signal was observed which could be used as the signal. The
important parameters of the detection system, such as, pH were optimized. The linear dynamic
range of the biosensor was1×10-9 to 1×10-6 M (r2=0.996) limits of detection of
2.5×10−10 M. In addition to the wide linear range response, the proposed method demonstrated
acceptable sensitivity, repeatability and long-term stability. Future experiments could be performed
to examine several other effective factors so as to decrease the influence of the environment and
investigate its application to FFTSWV detection.