Prudently designed Se@fMWCNT as a peroxidase mimicking nanozyme for distinctive electrochemical detection of H2O2 and glutathione

Abstract

Nanozymes are nanomaterials with enzymatic characteristics that are used to overcome the challenges associated with naturally occurring enzymes. A peroxidase mimicking nanozyme has been developed in this work, which has ability in the reduction of hydrogen peroxide (H₂O₂) to water, by oxidising the substrates in the presence of H₂O₂. We have designed and developed a neoteric Se@fMWCNT nanocomposite with peroxidase mimicking activity for electrochemical detection of H₂O₂ and glutathione (GSH). The choice of selenium (Se) was inspired by the natural enzymatic antioxidant glutathione peroxidase, which has Se as its active centre. Before preparation of the nanocomposite, MWCNT was functionalized with acid to obtain functionalized MWCNT, in order to improve biocompatibility and to increase conductivity by providing abundant active sites for the successful incorporation of Se. The as-synthesized nanocomposite was immobilized on a glassy carbon electrode, which could then be used for amperometric detection of the analytes H₂O₂ and GSH at neutral pH. The fabricated sensor exhibits a linear detection range of 50 nM–1.4 μM and a limit of detection (LOD) of 18.23 nM for H₂O₂, and a range of 50–450 μM and 500 μM–1.5 mM for GSH determination, with an LOD of 19.2 μM.