Search

Abnormal expression of hydrogen peroxide (H 2 O 2) elucidates cell dysfunctions and might induce the occurrence and deterioration of various diseases. However, limited by its ultralow level under pathophysiological conditions, intracellular and extracellular H 2 O 2 was difficult to be detected accurately. Herein, a colorimetric and homogeneous electrochemical dual-mode biosensing platform was constructed for intracellular/extracellular H 2 O 2 detection based on FeS x /SiO 2 nanoparticles (FeS x /SiO 2 NPs) with high peroxidase-like activity. In this design, FeS x /SiO 2 NPs were synthesized with excellent catalytic activity and stability compared to natural enzymes, which improved the sensitivity and stability of sensing strategy. 3,3′,5,5′-Tetramethylbenzidine (TMB), as a multifunctional indicator, was oxidized in the presence of H 2 O 2 , generated color changes and realized visual analysis. In this process, the characteristic peak current of TMB decreased, which could realize the ultrasensitive detection of H 2 O 2 by homogeneous electrochemistry. Accordingly, by integrating visual analysis ability of colorimetry and the high sensitivity of homogeneous electrochemistry, the dual-mode biosensing platform exhibited high accuracy, sensitivity and reliability. The detection limits of H 2 O 2 were 0.2 μM (S/N = 3) for the colorimetric method and 2.5 nM (S/N = 3) for the homogeneous electrochemistry assay. Therefore, the dual-mode biosensing platform provided a new opportunity for highly accurate and sensitive detection of intracellular/extracellular H 2 O 2. [Display omitted] • A CM-EC dual-mode biosensing platform was constructed. • FeS x /SiO 2 nanoparticles with high peroxidase-like activity were synthesized. • The intracellular/extracellular H 2 O 2 detection was realized. • This method can be applied in cell samples without any pretreatment. [ABSTRACT FROM AUTHOR]