Hierarchical graphene/nanorods-based H2O2 electrochemical sensor with self-cleaning and anti-biofouling properties

Detection of H2O2 in bio-fluids plays an important role in early-diagnosis of many diseases, and thus the development of electrochemical H2O2 sensors has been explored. However, constructing robust sensors that could self-clean and avoid biofouling is still challenging, because the complex compositions of bio-fluids could easily absorb to or even passivate the sensor electrode. In this work, we reported the development of H2O2 electrochemical sensor based on hierarchical vertical graphene/nanorods structure (vG/NRs) with self-cleaning and anti-biofouling properties. The hierarchical vG/NRs structure consisted of ZnO nanorods branched on vertical graphene nanowalls, which were fabricated through multiple steps of plasma enhanced chemical vapor deposition, atomic layer deposition and hydrothermal growth. The hierarchical vG/NRs after fluorination (vG/NRs-F) displayed excellent liquid repellence and anti-platelet adhesion properties. The vG/NRs-F was utilized as working electrodes and integrated as electrochemical sensors. H2O2 molecules in solution could access to the vG/NRs surface, inducing electrochemical signals for detection with reasonable sensitivity and selectivity. Meanwhile, the vG/NRs-F electrode could resist the contamination of biocomponents in blood serum after sensing experiment, enabling stable sensing of H2O2 without interfering by biofouling. Our work offers a promising strategy to design self-cleaning and anti-biofouling sensors with extended applicability for detection in complex biological fluids.