An amperometric biosensor for the detection of hydrogen peroxide released from human breast cancer cells.

The rapid, accurate and sensitive determination of hydrogen peroxide (H(2)O(2)) is of great significance in the physiological, pathological and environmental fields. In this work, we have proposed a highly sensitive and selective amperometric biosensor for the detection of extracellular H(2)O(2) released from human breast cancer cells with the help of a sequence-specific peptide. Since the peptide immobilized on the electrode surface can specifically bind with horseradish peroxidase (HRP) in a favorable orientation, which then well promotes the catalytic activities of the immobilized enzyme toward the reaction of o-phenylenediamine and H(2)O(2), the proposed biosensor can detect H(2)O(2) in a wide linear range from 1.0×10(-7) M to 1.0×10(-4) M with a low detection limit of 3.0×10(-8) M. It can be also directly used to efficiently trace extracellular H(2)O(2) released from human breast cancer cells MCF-7. Furthermore, the reproducibility, stability and selectivity of the biosensor are also quite well compared with the previous report, so our biosensor might be potentially useful in physiological and pathological detection of H(2)O(2) in the future.