In situ decorating the surface and interlayer of montmorillonite with Co0.5Ni0.5Fe2O4 nanoparticles: A sustainable, biocompatible colorimetric platform for H2O2 and acetylcholine

Originated from nature and used for nature is a way of sustainable development. In this work, montmorillonite (MMT), a natural two-dimensional (2D) layered mineral, the surface and interlayer of which were nano-decorated by chemical synthesis technique was applied in biological detection field. Magnetic ferrite (Co0.5Ni0.5Fe2O4) was anchored on the surface and intercalated in the interlayer of montmorillonite, which served as a competitive candidate of enzyme mimics. Cytotoxicity test toward HUVEC and Hela cells verified the good biocompatibility of Co0.5Ni0.5Fe2O4-MMT, guaranteeing its safety in biological applications. Based on the peroxidase-like activity of Co0.5Ni0.5Fe2O4-MMT, a colorimetric sensing platform for H2O2 was established by a facile mix-and-detect approach with the detection limit of 0.565 µM (3σ/slope). It was implied that the peroxidase-like activity of Co0.5Ni0.5Fe2O4-MMT was originated from generation of ·OH and ·O2− produced from catalytic decomposition process of H2O2. Coupled with cascaded catalytic reactions of ACh, a facile and efficient sensing platform for ACh with satisfactory anti-interference ability was established. Thus, all these remarkable features highlighted the superiority of Co0.5Ni0.5Fe2O4-MMT, and endowed it with a powerful competitiveness in the fields of environmental assessing, biosensing, and disease monitoring.