In Situ Fabrication of Nanoceria with Oxidase-like Activity at Neutral pH: Mechanism and Boosted Bio-Nanozyme Cascades

Abstract

Catalytic cascades have drawn much attention by avoiding the isolation of intermediates and due to high atom economy. Yet, developing an efficient, one-pot biocatalytic cascade remains challenging. Combined with the selectivity of biological enzymes and tunable activity of nanozymes, we herein demonstrate an effective bio-nanozyme cascade formed by glucose oxidase (GOx) and in situ-generated nanoceria. The prepared H2O2–nanoceria complex shows strong oxidative activity for common chromogenic substrates under physiological conditions, which are the optimal reaction conditions for most biological enzymes. Interestingly, GOx not only provides H2O2 for the second step reaction but also simultaneously leads to 7.4-fold enhancement of activity. We characterized the process of in situ generation of nanoceria at pH 7.0 and how proteins boost the activity by enhancing product desorption. In addition, the proposed one-pot bio-nanozyme cascade shows high stability and analytical performance for serum glucose with a detection limit of 5 μM.

Nanoceria-Based Artificial Nanozymes: Review of Materials and Applications

“…In the current situation, it is still a challenge that the OXD activity is low at physiological pH. , As a result, Zhang et al found that glucose oxidase CeO 2 NMs induced a cascade-nanozyme in which chromogenic substrates exhibited strong oxidative reactions. This study provides a new idea for promoting biomimicry catalytic cascade reactions in neutral conditions.…”

Light-activated carbon dot nanozyme with scandium for a highly efficient and pH-universal bio-nanozyme cascade colorimetric assay

“…Numerous strategies have been developed to enhance the selectivity of nanozyme-based sensors, including the design of bio-nanozyme cascades, [11][12][13][14] nanozyme-linked immunoassays, 15,16 and DNA/aptamer-coupling systems. 5,7 Among them, cascade catalysis has attracted much attention due to the superiority of enzymes.…”

β-Cyclodextrin Stabilized Nanoceria for Hydrolytic Cleavage of Paraoxon in Aqueous and Cationic Micellar Media

“…The occurrence of two ionic valencies (Ce 3+ /Ce 4+ ) on the active sites of nanoceria is responsible for the oxygen vacancy generation on the surface, which facilitates the phosphohydrolase activity of CeO 2 NPs. − Because of their ionic valency state, they behave as radical scavengers . Nanoceria exhibit pH-dependent variation of surface charges (negative, positive, or neutral) and other specific properties like homogenization, dispersion, and stabilization in aqueous solutions, which help in its application as oxidase, catalase, biomolecule adsorbent, sensors, , etc. Recent advancements in research have proven the enzyme mimetic like activity and catalytic phosphorylation activity of CeO 2 NPs with several biomolecules such as DNA, RNA, nucleic acid, and peptides. − …”

“…Nanoceria exhibit pH-dependent variation of surface charges (negative, positive, or neutral) and other specific properties like homogenization, dispersion, and stabilization in aqueous solutions, which help in its application as oxidase, catalase, biomolecule adsorbent, sensors, , etc. Recent advancements in research have proven the enzyme mimetic like activity and catalytic phosphorylation activity of CeO 2 NPs with several biomolecules such as DNA, RNA, nucleic acid, and peptides. − …”