A facile homogeneous electrochemical biosensing strategy based on displacement reaction for intracellular and extracellular hydrogen peroxide detection.

Abstract

Traditional electrochemical hydrogen peroxide (H2O2) assays all indispensably require the immobilization of enzyme or nanomaterials on electrode surface. These complex electrode surface modifications are laborious and time-consuming. To overcome such limitations, we developed here a facile homogeneous electrochemical biosensor based on displacement reaction for detection of intracellular and extracellular H2O2 produced by living cells. Methylene blue-labeled short single-stranded DNA strand (DNA-MB) was ingeniously designed as the reporter, which was adsorbed on CeO2 nanoparticles to result in low electrochemical signal. In the presence of H2O2, DNA-MB was released from CeO2 nanoparticles, leading to the significant enhancement of current signal. Therefore, a simple homogeneous electrochemical H2O2 assay is successfully achieved. This strategy also displays excellent anti-interference capability and reproducibility for H2O2 determination. More importantly, this method was capable of conveniently realizing intracellular and extracellular H2O2 assay. Thus, with the excellent merits of simplicity, rapidness, good repeatability, high specific and sensitivity, the proposed strategy has great potential to be applied in exploring the roles of H2O2 in physiological and pathological processes.