Self-assembled reduced graphene oxide-cerium oxide nanocomposite@cytochrome c hydrogel as a solid electrochemical reactive oxygen species detection platform

Monitoring of aberrant cellular levels of reactive oxygen species (ROS) has been a challenging task due to their shorter half-life and low concentration. Herein, a hybrid alginate-polyacrylamide hydrogel was preparedviaanin situself-assembly of reduced graphene oxide-cerium oxide nanocomposite (rGO-CeO2) and cytochromec(Cytc) and employed for electrochemical detection of ROS. The hydrogel platform, on one hand, provided a very large electroactive surface coverage and effectively increased the reactivity of Cytc, and, on the other hand, integrated the rGO-CeO(2)nanocomposite for enhancing electrochemical signals and structural stability. The formation of the rGO-CeO2@Cytchydrogel was confirmed through various microscopic and spectroscopic techniques. Besides, the electrochemical characteristics of rGO-CeO2@Cytchydrogel-modified screen-printed electrodes were investigated through cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. For the detection of ROS, CV and DPV measurements were carried out to monitor the concentration-dependent changes in current responses. The prepared sensor exhibited a selective and excellent linear response towards hydrogen peroxide (H2O2), hydroxyl radical ((OH)-O-center dot) and superoxide anion radical (O-2(center dot-)) in the desired concentration range with detection limits of 0.166 mu M, 0.338 mu M and 0.229 mu M, respectively. Taken together, these hybrid hydrogels based on electrochemical interfaces could be potential candidates for real time assessment of intracellular ROS levels, with implications for unraveling ROS-related disease mechanisms.