pH-Responsive Morphology-Controlled Redox Behavior and Cellular Uptake of Nanoceria in Fibrosarcoma

Abstract

The present work reports structural/microstructural correlations with biological performance for three nanoceria morphologies, aiming to elucidate the major factors in their interactions with fibrosarcoma. These include the pH of the in vitro medium and the crystallinities, stoichiometries, surface areas and chemistries, and maximal oxygen vacancy concentrations ([VO ••]Max). Although the [VO ••]Max is dominant in the redox behavior, the role of the morphology was manifested in the order of effectiveness of the redox regulation, which was nanocubes (NC) < nanorods (NR) < nanooctahedra (NO). The proposed mechanism illustrates the role of VO •• in explaining antioxidant behavior at physiological pH 7.4 and prooxidant behavior in the tumor microenvironment pH 6.4. Cellular uptake at pH 7.4 was dominated by the morphology of the nanoparticle, demonstrating the order NO < NC < NR. Control of the [VO ••]Max, morphology, and dependent structural and microstructural parameters can be used to optimize the uptake and redox performance of nanoceria.

Design strategies for ceria nanomaterials: untangling key mechanistic concepts

“…51 In contrast, most reports of the synthesis of CeO 2Àx typically detail procedures based on precipitation and hydrothermal synthesis, which have been done at considerably lower temperatures (r200 1C). However, in the case of CeO 2Àx , the ready Ce 4+ 2 Ce 3+ redox switching, even at room temperature under the influence of pH change, 6,14 demonstrates that at least some point defects in CeO 2Àx (viz., surface defects) are mobile at low temperatures.…”

“…12 It also has therapeutic prospects in biomedicine, [11][12][13] cancer treatments, 12 and neurodegenerative disorder treatment 13 owing to its controllable and pH-dependent Ce 4+ 2 Ce 3+ redox switching capability. 14 The oxygen storage and redox capacities of CeO 2Àx are largely dependent on the type and concentrations of defects, particularly oxygen vacancies, which depend on the particle morphologies and associated exposed crystallographic surfaces. [14][15][16][17] More specifically, CeO 2Àx has been emerging as a significant functional material, including as catalysts for automotive catalytic convertors (three-way catalysts), steam reforming, watergas shift reaction, hydrocarbon reforming, dehalogenation, and hydrogenation; as catalyst support; in fuel cells (as electrolyte in solid oxide fuel cells and oxygen permeation membrane in polymer exchange membrane fuel cells); as electrochromic films; as sensors for O 2 , NO, and hydrocarbons; and as ultraviolet absorbents.…”

“…14 The oxygen storage and redox capacities of CeO 2Àx are largely dependent on the type and concentrations of defects, particularly oxygen vacancies, which depend on the particle morphologies and associated exposed crystallographic surfaces. [14][15][16][17] More specifically, CeO 2Àx has been emerging as a significant functional material, including as catalysts for automotive catalytic convertors (three-way catalysts), steam reforming, watergas shift reaction, hydrocarbon reforming, dehalogenation, and hydrogenation; as catalyst support; in fuel cells (as electrolyte in solid oxide fuel cells and oxygen permeation membrane in polymer exchange membrane fuel cells); as electrochromic films; as sensors for O 2 , NO, and hydrocarbons; and as ultraviolet absorbents. [18][19][20] Conventionally, it is well known as a glass polishing compound and, more recently, it has been used in both biomedicine as a redox catalyst for cell therapies and in environmental chemistry as a photocatalyst for water and air purification.…”

Regulation of Ce (Ⅲ) / Ce (Ⅳ) ratio of cerium oxide for antibacterial application

“…At basic physicochemical pH, Ce (Ⅲ)/Ce (Ⅳ) couple exhibits antioxidant properties by scavenging reactive oxygen species (ROS). At acidic pH, the Ce (Ⅲ)/Ce (Ⅳ) couple shows prooxidant properties by producing ROS ( Mehmood et al., 2018 ). This unique redox potential of cerium oxide can be used to provide protection for normal cells and exhibit cytotoxic effects for bacteria in an acidic environment.…”

Enhanced Artificial Enzyme Activities on the Reconstructed Sawtoothlike Nanofacets of Pure and Pr-Doped Ceria Nanocubes

“…The biomimetic enzyme activities of nanoceria have been studied previously with wide application in biomedicine and environmental protection. , Depending on the aqueous solution conditions, nanoceria exhibits versatile performances, such as mimicking oxidase, superoxide dismutase, peroxidase, hydroxyl radical scavenger, phosphatase, etc. , In order to investigate the effects of Pr modification and thermal treatment on CeO 2 NCs, three distinctive and characteristic capabilities, mimicking oxidase, hydroxyl radical scavenger, and phosphatase, which represent the oxidizing, reducing, and hydrolytic properties, respectively, have been evaluated in this work.…”