Decreasing Crystallinity is Beneficial to the Superoxide Dismutase‐like Activity of Ceria Nanoparticles

Abstract

Ceria nanoparticles were classified as nanozymes because they are able to mimic the activities of some natural enzymes such as superoxide dismutase (SOD), catalase, oxidase and photolyase under given conditions. These functions have driven studies to explore the factors that could promote ceria nanoparticle enzyme activities. Accordingly, factors including size, shape, exposed plane and surface coating that could modulate the enzymatic activities of ceria nanoparticles have been explored. In the present study, we investigated the relationship between ceria nanoparticle crystallinity and SOD-like activity. Two groups of ceria nanoparticles with sizes of several nanometers and tens of nanometers in each group were synthesized with different crystallinities. The ceria nanoparticle crystallinities were closely connected to their Ce 3 + /Ce 4 + ratio, where the lower crystallinity resulted in a higher Ce 3 + concentration and vice versa. The catalytic activity evaluation results indicated that the nanoparticles featuring lower crystallinity exhibited higher SOD-like activity even though the nanoparticles had a smaller specific surface area. The crystallinity-dominated SOD-like activity variation could be sensed by cells, as the nanoparticles featuring lower crystallinity could better protect the cells from paraquat-induced oxidative stress. Therefore, decreasing crystallinity could be an effective way to achieve highly active ceria nanoparticles for SOD-related biological applications.

Hybrid Polyelectrolyte Capsules Loaded with Gadolinium-Doped Cerium Oxide Nanoparticles as a Biocompatible MRI Agent for Theranostic Applications

“…It was previously shown that the synthesis of cerium oxide nanoparticles under mild conditions using hydrothermal methods makes it possible to obtain nanoparticles with a low level of crystallinity and a higher content of Ce 3+ , which ensures their high antioxidant activity. Conversely, cerium oxide nanoparticles prepared using prolonged high-temperature annealing show negligible enzyme-like properties and are unable to protect human MSCs from oxidative stress [ 28 ]. The degree of crystallinity could also affect the biodegradability of ceria NPs.…”

Study on chitosan/gelatin hydrogels containing ceria nanoparticles for promoting the healing of diabetic wound

“…The thermal decomposition method was used to create four sizes of CNPs, and were then modified with the PEG600 diacid described in our previous studies, 46,47 which were described in details in the supporting information.…”

“…The surface composition of CNPs was analyzed by X‐ray photoelectron spectroscopy (XPS, ESCALAB 250Xi, Thermo Scientific, USA) with Al‐K α radiation (1486 eV), base pressure 10 −9 mbar, and pass energy 50 eV. The spectra were deconvoluted into 10 peaks based on the final state occupation of the Ce 3d level from 875 to 920 eV by the XPSPEAK41 software 35,47 . FT‐IR spectroscopy with ATR equipment (Specturm Two, Perkin Elmer, USA) and thermogravimetric analysis (TGA) analyzer (SDT650, TA, USA) were utilized to characterize the surface modification of CNPs.…”

Length‐Controlled Construction of Ceria Nanowires with Ultrafine Diameter and Stable Morphology for Targeted Acute Lung Injury Therapy

“…The O 2 •− scavenging capability was tested by the previous procedures. [ 31 ] The reaction was built up by a working solution and a testing solution. The working solution contained EDTA‐2Na (800 µL, 0.1 M), nitrotetrazolium blue chloride (300 µL, 2 m m ), riboflavin (200 µL, 0.6 m m ), and sodium phosphate buffer (11.4 mL, 10 m m , pH 7.8).…”