Reduced graphene oxide-ZnO nanocomposite based electrochemical sensor for sensitive and selective monitoring of 8-hydroxy-2'-deoxyguanosine.

Developing reliable and feasible electrochemical sensors for the detection of 8-hydroxy-2'-deoxyguanosine (8-OHdG) is important because the urinary level of 8-OHdG is related to cancer disease. Moreover, the co-existed uric acid (UA) as an interference severe affects the sensitive detection of 8-OHdG. Herein, sensitive monitoring of 8-OHdG was conducted using a nanocomposite of reduced graphene oxide (rGO) and ZnO nanoparticles (ZnO@rGO) as the sensing material. This nanocomposite was prepared via in-situ reduction of GO with Zn powders. Compared with those obtained on the unmodified glassy carbon electrode (GCE) and GO modified GCE (GO/GCE) the oxidation signals of 8-OHdG are significantly enhanced on the ZnO@rGO nanocomposite coated GCE (ZnO@rGO/GCE). Moreover, uricase has been employed successfully to eliminate the interferences of UA. A large amount of UA did not affect the oxidation signals of trace level of 8-OHdG. The linear range for the detection of 8-OHdG using ZnO@rGO/GCE was from 5.0 to 5000.0 nM. The detection limit was 1.25 nM calculated from a three-signal-to-noise ratio. The developed monitoring system is sensitive and selective for the determination of 8-OHdG and thus useful in practical applications, such as for the monitoring of 8-OHdG in the clinic urine samples.