Development of DNA electrochemical biosensor based on immobilization of ssDNA on the surface of nickel oxide nanoparticles modified glassy carbon electrode

A sensitive electrochemical method for DNA hybridization based on immobilization of DNA probe and [Ru(NH3)(5)Cl]PF6 complex onto nickel oxide nanomaterials (NiOx(np)) modified glassy carbon electrode was developed. Due to strong affinity of NiOxnp for phosphate groups, oligonucleotides probe with a terminal 5'-phosphate group was attached to the surface of the modified electrode. DNA immobilization and hybridization were characterized by electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry using K3Fe(CN)(6)/K4Fe(CN)(6) and [Ru(NH3)(5)Cl]PF6 as probe and indicator, respectively. The Ru-complex current response indicates only the complementary sequence showing an obvious current signal in comparison to non-complementary and three or single point mismatched sequences. The fabricated biosensor possessed good selectivity and sensitivity for complementary probe, taxon: 32630 tumor necrosis factor (TNF). The linear dynamic range, sensitivity and detection limit of the proposed biosensor were 4 x 10(-10) M to 1 x 10(-8) M, 34.32 nA nM(-1) and 6.8 x 10(-11) M, respectively. Excellent reproducibility and stability, quite simple and inexpensive preparation are the other advantages of proposed biosensor. (C) 2011 Elsevier B.V. All rights reserved.