Bienzyme reactions on cross-linked DNA scaffolds for electrochemical analysis

Enzymes play an essential role in various detection technologies. We show here that interstrand cross-linked oligodeoxynucleotides (CL-ODNs) can provide stable scaffolds for efficiently coupling two types of enzymatic reactions on an electrode. Glucose can be electrochemically detected using glucose oxidase (GOx) and horseradish peroxidase (HRP). When both GOx and HRP were immobilized on an electrode surface by attachment at the termini of CL-ODNs, the current value was markedly increased compared with that obtained on a standard ODN scaffold. The relative orientation of the enzymes on the electrode strongly affected the current intensities. The CL-ODN also allowed GOx-HRP to form a complex on the tiny surface of a microelectrode, resulting in the imaging of local glucose distribution. These results suggest that CL-ODNs have potential utility in other sensing technologies.