Label-free electrogenerated chemiluminescence biosensing method for trace bleomycin detection based on a Ru(phen)3(2+)-hairpin DNA composite film electrode

Abstract

A novel label-free electrogenerated chemiluminescence (ECL) DNA-based biosensing method for the determination of trace bleomycin (BLM) was developed on basis of Fe(II)·BLM-mediated DNA strand scission and Ru(phen)3(2+) as an ECL probe. A thiolated ss-DNA, as substrate for BLMs, was self-assembled onto surface of a gold electrode to form a hairpin structure. Ru(phen)3(2+) was intercalated into the hairpin DNA structure. In the presence of Fe(II)·BLM, the hairpin DNA sequence undergoes the irreversible cleavage event under the oxidative effect of BLM with Fe(II) as a cofactor and the intercalated Ru(phen)3(2+) released from the gold electrode, which can be transduced into a significant decrease in ECL intensity. The ECL intensity versus the concentration of BLMs was linear in the range from 0.1 pM to 50 pM. The detection limit was 0.03 pM. This work demonstrates that using the sequence selectivity of DNA cleavage strategy for the fabrication of the label-free ECL biosensing method is a promising approach for the determination of antitumor drugs.