Electrochemical analysis of 8-hydroxy-2′-deoxyguanosine with enhanced sensitivity based on exonuclease-mediated functional nucleic acid.

Abstract In this work, an electrochemical method for sensitive analysis of 8-hydroxy-2′-deoxyguanosine, a key biomarker that is widely used to study oxidative injury-related diseases, is proposed based on exonuclease-mediated functional nucleic acid. In the design, exonuclease can not only distinguish the existence of target, but also suppress the background noise, thus the sensitivity can be enhanced. Moreover, DNAzyme designed in the functional nucleic acid can further improve the sensitivity of the analysis during signal generation process. Therefore, exonuclease-mediated functional nucleic acid may ensure high sensitivity of the assay. Further studies reveal that the detection of 8-hydroxy-2′-deoxyguanosine can be achieved with a linearity from 0.01 nM to 7.0 μM and a detection limit of 6.82 pM. The new method has also been successfully applied to the determination of 8-OHdG in urine with good results, indicating its great potential for practical use. Graphical abstract fx1 Highlights • A novel electrochemical biosensor for 8-OHdG detection has been developed. • The combination of aptamer and DNAzyme ensures the high selectivity and sensitivity of the assay. • The background signal is reduces by exonuclease. • The biosensor has been applied for urine samples detection with satisfactory results. [ABSTRACT FROM AUTHOR]