Haloperoxidase Mimicry by CeO_2–x Nanorods of Different Aspect Ratios for Antibacterial Performance

Abstract

Cerium oxide nanorods as haloperoxidase started to gain attention due to their great potential as a biologically benign antifoulant. The antibacterial efficiency induced by haloperoxidase activity of cerium oxide nanorods with different aspect ratios is currently unexplored. Herein, the relationship between different aspect ratios, haloperoxidase activities, and antibacterial effects was systematically investigated. CeO2–x nanorods with different aspect ratios were synthesized by merely controlling NaOH concentrations via a traditional hydrothermal method. The CeO2–x nanorods exposed {110} facets and supplied the Ce3+ sites to ensure the haloperoxidase activities. The haloperoxidase activities of CeO2–x nanorods were varied with their aspect ratios because of their differences in Ce3+ concentration, oxygen vacancies, and band gap energies. More importantly, their antibacterial efficiency was in the same order as their haloperoxidase activity, indicating that natural intermediates (HOBr) are induced by the haloperoxidase mimicking activity to achieve antibacterial efficiency. This work provides a guide for improving antibacterial efficiency of cerium oxide nanorods by modulating their aspect ratios.

Biocatalytic Nanomaterials: A New Pathway for Bacterial Disinfection

“…[ 40 ] Copyright 2015, Wiley‐VCH; BCNs with chemical auxiliaries: Reproduced with permission. [ 41 ] Copyright 2020, American Chemical Society; energy sensitive BCNs: Reproduced with permission. [ 42 ] Copyright 2018, American Chemical Society; EPS decomposition: Reproduced with permission.…”

“…Similarly, CeO 2‐x nanorods were also proved to enable morphology‐dependent HPO‐mimetic properties, which sharply reduced bacterial survival rates after only 5s of coincubation (Figure 4C,D). [ 41 ] It is worth noting that as compared to vanadium‐based nanocatalysts, cerium‐based nanocatalysts show much higher biocompatibility, suggesting new possibilities for clinical antibacterial treatment.…”

Will the Bacteria Survive in the CeO2 Nanozyme-H2O2 System?

“…Therefore, the exploration of new antimicrobial strategies is urgently demanded [ 13 , 14 , 15 , 16 ]. Nanozyme-based antibacterial strategies have been recently demonstrated to be a promising new approach for bacterial infection treatment [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. For example, Qu et al developed graphene quantum dots (GQDs) that can act as a peroxidase mimic to enhance the antibacterial capacity of H 2 O 2 and can be used for wound disinfection [ 25 ].…”

Haloperoxidase-mimicking CeO2−xnanorods for the deactivation of human coronavirus OC43

“…The HPO-like properties of CeO 2−x nanorods have been attributed to the facile redox cycle enabled by the Ce 3+ /Ce 4+ states, via the reaction: CeO 2 ↔ CeO 2−x + x/2O 2 . 21 Nevertheless, despite the extensive studies on the antifouling, 21 antibacterial, 25 and antioxidant 17 properties of CeO 2−x nanorods, their antiviral properties remained unknown.…”

“…CeO 2−x nanorods with different lengths and aspect ratios were synthesized via an established hydrothermal method. 21,25 The hydrothermal approach leverages the dissolution and recrystallization of CeO 2−x to control the growth of the nanoparticles, 26 where dissolved hydroxide ions promote the nucleation of cerium hydroxide. As such, lengths of the nanorods were varied by tuning the concentration of NaOH to be 1 M, 5 M, and 9 M, and subsequently confirmed using transmission electron microscopy (TEM) (Fig.…”