Interaction between immobilized DNA and tris(bpy) osmium(II/III) complex

The interaction between a tris(bipyridyl)osmium (II/III) ion (osmium comple x) and immobilized DNA was studied. The amount of immobilized DNA on the pr epared carbon paste electrode (surface area; 0.66-2.37 X 10(-2) cm(2)) was 0.26-2.78 X 10(-4) mol cm(-2) Compared with the bare porous electrode (584 mV), the equilibrium potential of osmium complex with the immobilized singl e strand DNA electrode shifted to the higher side (650 mV). On the other ha nd, the equilibrium potential of one with the immobilized double strand DNA (dsDNA) electrode shifted to the lower side (542 mV). These results sugges t that the osmium complex interacted specifically with dsDNA. The amount of the osmium complex on immobilized dsDNA electrodes was determined and it g ave a good linear plot in the concentration range of 0.5 to 4 mM. (C) 2000 Elsevier Science S.A. All rights reserved.