Natural Nanominerals Show Enzyme-Like Activities

Abstract

Natural nanominerals (NNMs) are progressively deposited during earth’s formation. They have shown a broad range of applications from industrial catalysis, environmental treatment, and earth science to pharmaceutics due to their unique nanostructures and characteristics. Here, we first report that NNMs have intrinsic enzyme-like properties and show good biocompatibility. First, we characterized the morphology and structure of the six most representative NNMs including sepiolite, attapulgite, halloysite, montmorillonite, kaolinite, and diatomite by SEM, TEM, and XRD. Then, we quantitatively tested their peroxidase- (POD-), catalase- (CAT-), oxidase- (OXD-), and superoxide dismutase- (SOD-) like activities. The results indicate that different kinds of NNMs show varying degrees of POD-like, CAT-like, and SOD-like activities and minor OXD-like activity. Finally, we tested their cytotoxicity and found that the selected representative NNMs have no or less influence on cell viability, showing high biosafety. At present, NNMs have been widely used, mostly focusing on the physical and chemical properties, such as luminescence and conductivity. Our work promotes the understanding of NNMs, providing a new direction for the better application of NNMs.

Attapulgite Doped with Fe and Cu Nanooxides as Peroxidase Nanozymes for Antibacterial Coatings

“…Attapulgite (ATP) is a natural and available nanomineral with a special layered-chain construction and has a large specific surface area (>100 m 2 g –1 ), strong adsorption capability, and dynamic nature of the surface, providing rapid mass transport and abundantly accessible sites for efficient catalytic reactions. − In addition, the good biocompatibility and the excellent stability of ATP make it possible to be applied as a nanozyme. Our previous study has confirmed that ATP showed intrinsic POD-like activities . However, due to the natural properties of ATP such as low metal contents and inertness, the POD-like activity of ATP is too low to be applied in practical use.…”

“…Two kinds of antibacterial methods were evaluated to fully assess the disinfection performance of Fe-Cu/ATP by using E. coli and S. aureus as the models. One is a short-time method where E. coli and S. aureus were mixed with samples with or without an ultralow concentration of H 2 O 2 (0.5 mM) at 37 °C for 1 h. As shown in Figure 5, pristine ATP possesses intrinsic POD-like activity, 26 which can kill bacteria due to its oxidizing properties by producing • OH and • O 2 − radicals, exhibiting some degree of antibacterial properties, which may be due to the isomorphic metallic elements in the structure. Notably, Fe-Cu/ATP with an enhanced POD-like activity has an antibacterial rate of 100% for both E. coli and S. aureus.…”

“…Our previous study has confirmed that ATP showed intrinsic POD-like activities. 26 However, due to the natural properties of ATP such as low metal contents and inertness, the POD-like activity of ATP is too low to be applied in practical use. Introducing additional active components and increasing the specific surface area are potential strategies to improve the nanozymic activity of natural ATP.…”