Ultrasensitive photoelectrochemical sensing of Pb2+ based on allosteric transition of G-Quadruplex DNAzyme.

Abstract: A sensitive photoelectrochemical (PEC) approach for Pb2+ sensing was achieved firstly with the coupling of G-quadruplex-based DNAzyme and biocatalytic precipitation (BCP) on a CdS quantum dots electrode. Pb2+ can induce the conformational change of K+-stabilized G-quadruplex-based DNAzyme, leading to the decrease of the catalytic activity to H2O2-mediated 4-chloro-1-naphthol oxidation (BCP reaction). From the respective BCP reaction that monitors the event of DNAzyme deactivation, a novel PEC Pb2+ sensor could be realized with a detection limit of 1.0×10−8 M. [Copyright &y& Elsevier]