Enhanced nonenzymatic sensing of hydrogen peroxide released from living cells based on Fe3O4/self-reduced graphene nanocomposites

Abstract

A novel, sensitive, nonenzymatic amperometric sensor for the reliable detection of extracellular H₂O₂ released from living cells was fabricated based on Fe₃O₄/reduced graphene oxide (Fe₃O₄/rGO) nanocomposites, which were prepared using a simple and cost-effective one-pot approach. Electrochemical performances of the Fe₃O₄/rGO nanocomposites modified glassy carbon electrode (GCE) were studied. The results demonstrated that this H₂O₂ sensor exhibited excellent electrocatalytic performance towards the reduction of H₂O₂ at a potential of −0.3 V in the wide linear concentration range from 0.001 to 20 mM with a high sensitivity of 387.6 μA mM⁻¹ cm⁻² and a detection limit as low as 0.17 μM (S/N = 3), which was lower than certain enzymes and noble metal nanomaterials-based biosensors. Moreover, good anti-interference property, reproducibility, and long-term stability of the enzymeless sensor were achieved. Because of these remarkable analytical advantages, a novel, effective approach for the detection of extracellular H₂O₂ released from HeLa cells stimulated by CdTe quantum dots (QDs) was established by the constructed sensor. Since H₂O₂ is a byproduct of several oxidative biological reactions, this work could be applied to study the downstream biological effects of various stimuli in pathophysiology, and may expand the application of Fe₃O₄-based nanomaterials in the field of electrochemical sensing and bioanalysis.