Room temperature ionic liquid doped DNA network immobilized horseradish peroxidase biosensor for amperometric determination of hydrogen peroxide.

A novel electrochemical H(2)O(2) biosensor was constructed by embedding horseradish peroxide (HRP) in a 1-butyl-3-methylimidazolium tetrafluoroborate doped DNA network casting on a gold electrode. The HRP entrapped in the composite system displayed good electrocatalytic response to the reduction of H(2)O(2). The composite system could provide both a biocompatible microenvironment for enzymes to keep their good bioactivity and an effective pathway of electron transfer between the redox center of enzymes, H(2)O(2) and the electrode surface. Voltammetric and time-based amperometric techniques were applied to characterize the properties of the biosensor. The effects of pH and potential on the amperometric response to H(2)O(2) were studied. The biosensor can achieve 95% of the steady-state current within 2 s response to H(2)O(2). The detection limit of the biosensor was 3.5 microM, and linear range was from 0.01 to 7.4 mM. Moreover, the biosensor exhibited good sensitivity and stability. The film can also be readily used as an immobilization matrix to entrap other enzymes to prepare other similar biosensors.