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

Abstract

A sensitive electrochemical method for DNA hybridization based on immobilization of DNA probe and [Ru(NH 3) 5Cl]PF 6 complex onto nickel oxide nanomaterials (NiOx np) modified glassy carbon electrode was developed. Due to strong affinity of NiOx np 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 K 3Fe(CN) 6/K 4Fe(CN) 6 and [Ru(NH 3) 5Cl]PF 6 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 4×10 -10M to 1×10 -8M, 34.32nAnM -1 and 6.8×10 -11M, respectively. Excellent reproducibility and stability, quite simple and inexpensive preparation are the other advantages of proposed biosensor. © 2011 Elsevier B.V.