Amplified detection of bleomycin based on an electrochemically driven recycling strategy

The present work demonstrates a rapid and sensitive method for bleomycin (BLM) detection, taking advantage of an electrochemically driven recycling strategy. DNA probes, the substrate for BLM, are first immobilized on a gold electrode surface. Complexation of BLM with Fe2+ ions and oxygen may result in the production of the BLM·Fe3+ complex and free radicals, which may trigger an irreversible cleavage of DNA probes. Cyclic voltammetry is applied as a stimulus to regenerate the BLM·Fe2+ complex from Fe3+ species, subsequently initiating a new cleavage event. The electrochemically driven recycling of the BLM·Fe2+ complex may lead to the continuous strand scission of a large quantity of DNA probes, which can be transduced into significantly amplified electrochemical signals. With [Fe(CN)6]3−/4− as the redox species, BLM can be detected down to 0.74 pM within 10 min. Further studies reveal that the proposed method can also exhibit satisfactory performance in serum samples, and thus may provide a promising tool for the BLM assay in clinical diagnosis.