Stable enzymatic curve platform and ultrafast catalytic kinetic endows MnSiO3 oxidase mimic with high reliability and supersensitivity

Over the past decades, advanced nanomaterial mediated intrinsic enzymatic colorimetric biosensing has been widely explored in assays and diagnostics. However, low affinity towards substrate and unstable detected curve platform leads to unsatisfactory catalytic kinetic and weak ability to eliminate the interference from difference of individual operation time, significantly decreases their sensitivity and reliability. To our best knowledge, no enzymatic colorimetric detection nanoagents have been reported to have ultrafast catalytic kinetic and stable enzymatic curve platform with satisfactory and reliable accuracy. Herein, a MnSiO3 oxidase mimic was first reported with supersensitivity and high reliability in the paradigm for colorimetric detection of biothiols. The experiment results reveal that the supersensitivity is attributed to its ultrafast affinity towards substrate mediated an excellent catalytic kinetic (Km = 17 μM) and superior limit of detection (10 nM for GSH), which is superior to the previously reported methods. The presence of SiO32− ions further improves the stability of oxidized substrate, provides a stable detected curve platform (∼10 min) and finally exhibits a high reliable accuracy whether addition of test samples at any timepoint within 10 min, which could eliminate the interference of individual operation time. In addition, MnSiO3 is practicable for specific analysis of biological fluids (fetal calf serum and cancer cellula) and design of visual logic gates. Hence, this MnSiO3 oxidase provides a promising solution for biosensing with super-sensitivity and high reliability.