Graphene supported gold hollow sphere for real-time electrochemical detection of H2O2 released from cells

In this work, graphene undergoes twice oxidization to produce reoxidized-graphene oxide (ROGO), and then ROGO reacts with thiourea to obtain thiol-functionalized reduced ROGO (rROGO-SH), achieving reduction and surface thiolation. Subsequently, Au hollow spheres (Au HS) are decorated on rROGO-SH, and an electrochemical sensor is therefore fabricated by coating rROGO-S-Au HS on a glassy carbon electrode (GCE). rROGO-S-Au HS/GCE exhibits attractive electrochemical performance for H2O2 detection with a wide linear detection range (5 μM to 11.5 mM), low detection limit (5 μM), and good sensitivity (0.19 mA mM−1 cm−2). Due to its good performance for in-vivo detection, rROGO-S-Au HS/GCE can sensitively detect a trace amount of H2O2 released from living tumor cells. Hence, the rROGO-S-Au HS based electrochemical sensing platform shows great potential for online monitoring of H2O2 levels at tumor sites, which is beneficial for the rapid and sensitive diagnosis of cancer, as well as in vivo monitoring of tumor progression.