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Nano Research

Article Title

Probing hydroxyl radical generation from H2O2 upon plasmon excitation of gold nanorods using electron spin resonance: Molecular oxygen-mediated activation

Keywords

gold nanorod, oxygen activation, hydroxyl radical, plasmon catalysis, electron spin resonance

Abstract

Gold nanostructures are among the noble metal nanomaterials being intenselystudied due to their good biocompatibility, tunable localized surface plasmonresonance (SPR), and ease of modification. These properties give gold nanostructuresmany potential chemical and biomedical applications. Herein, wedemonstrate the critical role of oxygen activation during the decomposition ofhydrogen peroxide (H2O2) in the presence of photoexcited gold nanorods (AuNRs)by using electron spin resonance (ESR) techniques. Upon SPR excitation, O2 isactivated first, and the resulting reactive intermediates further activate H2O2 toproduce •OH. The reactive intermediates exhibit singlet oxygen-like (1O2-like)reactivity, indicated by 1O2-specific oxidation reaction, quenching behaviors,and the lack of the typical 1O2 ESR signal. In addition, by using the antioxidantsodium ascorbate (NaA) as an example, we show that hydroxyl radicals fromH2O2 activation can induce much stronger NaA oxidation than that in theabsence of H2O2. These results may have significant biomedical implications.For example, as oxidative stress levels are known to influence tumorigenesisand cancer progression, the ability to control redox status inside tumormicroenvironments using noble metal nanostructures may provide new strategiesfor regulating the metabolism of reactive oxygen species and new approachesfor cancer treatment.

Graphical Abstract

Publisher

Tsinghua University Press

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