▎ 摘　　要

In this work, a simple and new electrochemical biosensor based on a glassy carbon electrode (GCE) modified with a nanocomposite of polyaniline (PANI) and graphene oxide (GO) nanosheets for DNA detection was designed. The modification process was characterized by scanning electron microscopy (SEM) and electrochemical methods. The immobilization and hybridization processes were followed using electrochemical techniques and the experimental conditions were optimized, too. The electrochemical response for DNA hybridization was measured using the electrochemical impedance spectroscopy (EIS) method. The obtained calibration graph contains a linear range of 1.0 x 10(-16) M to 1.0 x 10(-8) M and a detection limit of 3.3 x 10(-17) M. The designed biosensor (ssDNA/PANI/GO/GCE) revealed high selectivity for the detection of the complementary sequences from non-complementary sequences, so the fabricated biosensor can be used for the detection of prostate cancer (PCa) DNA sequences.