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Chain-Breaking Antioxidant and Peroxyl Radical Trapping Activity of Phenol-Coated Magnetic Iron Oxide Nanoparticles

Superparamagnetic iron oxide nanoparticles (SPION) are important materials for biomedical applications, and phenol capping is a common procedure to passivate their surface. As phenol capped SPION have been reported to behave as antioxidants, herein, we investigate the mechanism underlying this activ...

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Autores principales: Scurti, Stefano, Caretti, Daniele, Mollica, Fabio, Di Antonio, Erika, Amorati, Riccardo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9219998/
https://www.ncbi.nlm.nih.gov/pubmed/35740061
http://dx.doi.org/10.3390/antiox11061163
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author Scurti, Stefano
Caretti, Daniele
Mollica, Fabio
Di Antonio, Erika
Amorati, Riccardo
author_facet Scurti, Stefano
Caretti, Daniele
Mollica, Fabio
Di Antonio, Erika
Amorati, Riccardo
author_sort Scurti, Stefano
collection PubMed
description Superparamagnetic iron oxide nanoparticles (SPION) are important materials for biomedical applications, and phenol capping is a common procedure to passivate their surface. As phenol capped SPION have been reported to behave as antioxidants, herein, we investigate the mechanism underlying this activity by studying the reaction with alkyl peroxyl (ROO(•)) radicals. SPION were prepared by coprecipitation of Fe(II) and Fe(III), using phenolic antioxidants (gallic acid, Trolox and nordihydroguaiaretic acid) as post-synthesis capping agents and by different purification procedures. The reactivity of ROO(•) was investigated by inhibited autoxidation studies, using styrene as an oxidizable substrate (solvent MeCN, 30 °C) and azo-bis(isobutyronitrile) as a radical initiator. While unprotected, bare SPION behaved as prooxidant, accelerating the O(2) consumption of styrene autoxidation, phenol capping provided a variable antioxidant effect that was dependent upon the purification degree of the material. Thoroughly washed SPION, containing from 7% to 14% (w/w) of phenols, had a low reactivity toward peroxyl radicals, while SPION with a higher phenol content (46% to 55%) showed a strong radical trapping activity. Our results indicate that the antioxidant activity of phenol-capped SPION can be caused by its release in a solution of weakly bound phenols, and that purification plays a major role in determining the properties of these materials.
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spelling pubmed-92199982022-06-24 Chain-Breaking Antioxidant and Peroxyl Radical Trapping Activity of Phenol-Coated Magnetic Iron Oxide Nanoparticles Scurti, Stefano Caretti, Daniele Mollica, Fabio Di Antonio, Erika Amorati, Riccardo Antioxidants (Basel) Article Superparamagnetic iron oxide nanoparticles (SPION) are important materials for biomedical applications, and phenol capping is a common procedure to passivate their surface. As phenol capped SPION have been reported to behave as antioxidants, herein, we investigate the mechanism underlying this activity by studying the reaction with alkyl peroxyl (ROO(•)) radicals. SPION were prepared by coprecipitation of Fe(II) and Fe(III), using phenolic antioxidants (gallic acid, Trolox and nordihydroguaiaretic acid) as post-synthesis capping agents and by different purification procedures. The reactivity of ROO(•) was investigated by inhibited autoxidation studies, using styrene as an oxidizable substrate (solvent MeCN, 30 °C) and azo-bis(isobutyronitrile) as a radical initiator. While unprotected, bare SPION behaved as prooxidant, accelerating the O(2) consumption of styrene autoxidation, phenol capping provided a variable antioxidant effect that was dependent upon the purification degree of the material. Thoroughly washed SPION, containing from 7% to 14% (w/w) of phenols, had a low reactivity toward peroxyl radicals, while SPION with a higher phenol content (46% to 55%) showed a strong radical trapping activity. Our results indicate that the antioxidant activity of phenol-capped SPION can be caused by its release in a solution of weakly bound phenols, and that purification plays a major role in determining the properties of these materials. MDPI 2022-06-14 /pmc/articles/PMC9219998/ /pubmed/35740061 http://dx.doi.org/10.3390/antiox11061163 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Scurti, Stefano
Caretti, Daniele
Mollica, Fabio
Di Antonio, Erika
Amorati, Riccardo
Chain-Breaking Antioxidant and Peroxyl Radical Trapping Activity of Phenol-Coated Magnetic Iron Oxide Nanoparticles
title Chain-Breaking Antioxidant and Peroxyl Radical Trapping Activity of Phenol-Coated Magnetic Iron Oxide Nanoparticles
title_full Chain-Breaking Antioxidant and Peroxyl Radical Trapping Activity of Phenol-Coated Magnetic Iron Oxide Nanoparticles
title_fullStr Chain-Breaking Antioxidant and Peroxyl Radical Trapping Activity of Phenol-Coated Magnetic Iron Oxide Nanoparticles
title_full_unstemmed Chain-Breaking Antioxidant and Peroxyl Radical Trapping Activity of Phenol-Coated Magnetic Iron Oxide Nanoparticles
title_short Chain-Breaking Antioxidant and Peroxyl Radical Trapping Activity of Phenol-Coated Magnetic Iron Oxide Nanoparticles
title_sort chain-breaking antioxidant and peroxyl radical trapping activity of phenol-coated magnetic iron oxide nanoparticles
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9219998/
https://www.ncbi.nlm.nih.gov/pubmed/35740061
http://dx.doi.org/10.3390/antiox11061163
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