▎ 摘　　要

A novel indicator-free DNA hybridization biosensor with a graphene-based nanocomposite as the enhanced sensing platform was developed for the detection of the BCR/ABL fusion gene in chronic myelogenous leukemia. The platform was constructed by homogenously distributing ordered FePt nanoparticles (NPs) onto the electrochemically reduced graphene oxide (ERGNO). The surface structure and electrochemical performance of the FePt/ERGNO nanocomposite were systematically investigated. Owing to the synergistic effects of FePt NPs and ERGNO with a large surface area and excellent electron transfer ability, the obtained nanocomposite greatly facilitated the sensing behavior for DNA detection, resulting in excellent sensitivity and selectivity. A remarkable change has been observed in the impedance spectra before and after hybridization of the probe single-stranded DNA (ssDNA) with the target DNA. Under the optimized conditions, the complementary target genes could be quantified in a wide range of 1.0 x 10(-14) to 1.0 x 10(-9) mol/L with a detection limit of 2.6 x 10(-15) mol/L. The approach does not need an oligonucleotide probe or target to be labeled previously, which makes it advantageous in terms of simplicity and noninvasiveness.