Efficient quenching of electrochemiluminescence from K-doped graphene–CdS:Eu NCs by G-quadruplex–hemin and target recycling-assisted amplification for ultrasensitive DNA biosensing

Based on the K-doped graphene–CdS:Eu NC composites and the nicking endonuclease (NEase) assisted strand-scission cycle, we have developed an ultrasensitive and selective electrochemiluminescence (ECL) DNA biosensor using the G-quadruplex–hemin-based DNAzyme which acts as an electrocatalyst for the reduction of H2O2, the coreactant of CdS:Eu NCs ECL.