A stochastic DNA walker electrochemiluminescence biosensor based on quenching effect of Pt@CuS on luminol@Au/Ni-Co nanocages for ultrasensitive detection of I27L gene

• Luminol@Au/Ni-Co NCs as ECL donors with excellent catalytic activity. • Pt@CuS nanocomposites were used as acceptor quenchers for signal-off sensor. • Stochastic DNA walker improved the sensitivity of ECL sensor. • The ECL sensor possessed splendid analytical performance for the detection of I27L. The common I27L mutations of the hepatocyte nuclear factor-1α (HNF1A) significantly increase the incidence of maturity-onset diabetes of the young (MODY). Hence, the establishment of an ultrasensitive detection strategy for I27L gene is crucial for the diagnosis and treatment of MODY. Herein, a signal-off electrochemiluminescence resonance energy transfer (ECL-RET) biosensor with effective target-induced stochastic DNA walker amplification was fabricated for I27L detection. In this biosensor, Prussian blue analogues (Ni-Co) nanocages/Au-supported luminol (luminol@Au/Ni-Co) were used as ECL donors and exhibited excellent luminous efficiency. On the other hand, Pt nanoparticles-grown on copper sulphide (Pt@CuS) were used as energy acceptors to quench the initial signal based on RET between luminol and CuS. Moreover, the autonomous locomotion of I27L assisted by Exo III is the key in this DNA walker biosensor, as it continually induces new digestion processes on the electrode surface and quenches signals caused by the introduction of numerous acceptors. The efficient donor/acceptor pairs and DNA walker amplification system of the ECL-RET allowed the proposed biosensor to effectively detect I27L with a wide linear range of 0.0001 to 100 nM and a limit of detection as low as 23 fM. Thus, the ECL-RET biosensor provides a promising sensing platform for the diagnosis and typing of diabetes.