The electrochemical properties of a Prussian blue (PB) electrode were improved by introducing cetyltrimethylammonium bromide (CTAB) and Au nanoparticles (AuNPs) into PB films. The novel hybrid films (PB/CTAB/AuNPs) were fabricated by electrodepositing PB and AuNPs in the presence of CTAB. The electrochemical behavior of the hybrid film in some supporting electrolyte (cations for the K+, Na+, or K+/Na+) was investigated in detail, and well-defined and reversible voltammetric responses were obtained in Na+-based electrolytes. The catalytic activity of the PB/CTAB/AuNPs electrode toward hydrogen peroxide (H2O2) reduction at a neutral pH was also investigated, and the results indicated that the electrochemical reduction of H2O2 in the presence of physiological levels of Na+ was superior to that of a PB-modified electrode. Moreover, the PB/CTAB/AuNPs electrode exhibited good performance, a low detection limit (0.1 mu M), and high stability at a wide range of concentrations (0.882-195 mu M). To determine the performance of PB nanocomposite electrodes in Na+-based phosphate buffers, an amperometric biosensor with a PB/CTAB/AuNPs electrocatalyst was developed. To fabricate this sensor, the enzyme was immobilized in sol-gel and was electrodeposited onto a PB nanocomposite film. The results indicated that the biosensor can be used at a wide range of concentrations (20-400 mu M) and possesses a low detection limit (7 mu M) for glucose. These characteristics demonstrate that PB nanocomposite film can be used as an electron mediator for biosensors in potassium-free phosphate buffers.

The Hexaaza macrocyclic copper(II) complex (Cu(II)L-1,8-Dihydroxyethyl-1,3,6,8,10,13-hexaazacyclotetradecane copper(II) perchlorate monohydrate) was synthesized and purified. The interaction of this complex with calf thymus DNA has been explored by using absorption, emission, viscosity measurements, electrochemical studies and DNA cleavage. All of the experimental results indicate that the complex bind to DNA by non-classical or partial intercalative interaction. The complex has also been found to promote the cleavage plasmid pBR 322, in the presence of H2O2 and ascorbic acid. The cleaving mechanism for the Cu(II)L complex has been proposed.

The hexaaza macrocyclic copper(II) complex Cu(II)L(L1,8-Dihydroxyethyl-1,3,6,8,10,13-hexaazacyclotetradecane), which has octahedral structure similar to some natural complexes, is synthesized and purified. In this study, oxidative breakage DNA by the reaction of Cu(II)L with H2O2 and ascorbate has been investigated by gel electrophoresis experiments. In electrochemical experiments, the on scDNA-modified glassy carbon electrode(GCE) is cleaved by the Cu(II)L and redox changing of the metal catalyst without adding any other reagents. Above all, the need for concentration of scDNA is much lower than that of gel electrophoresis experiments and the process of the performance is easy. Furthermore, Cyclic Voltammetry (CV) and A.C. Impedance, which are performed to monitor scDNA cleavage at the scDNA-modified glassy carbon electrode (GCE), are fast, simple and highly efficient. The mechanism of the damage can be suggested: Fenton.