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

• Published in: Nano research 2016-06, Vol.9 (6), p.1663-1673
• Main Authors: Wen, Tao, Zhang, Hui, Chong, Yu, Wamer, Wayne G., Yin, Jun-Jie, Wu, Xiaochun
• Format: Article
• Language: English
• Subjects: Activation; Antioxidants; Ascorbic acid; Atomic/Molecular Structure and Spectra; Biocompatibility; Biomedical materials; Biomedicine; Biotechnology; Cancer; Chemistry and Materials Science; Condensed Matter Physics; Electron paramagnetic resonance; Electron spin; Electron spin resonance; Excitation; Free radicals; Gold; Hydrogen peroxide; Hydroxyl radicals; Intermediates; Materials Science; Metabolism; Microenvironments; Nanomaterials; Nanorods; Nanostructure; Nanotechnology; Noble metals; Oxidation; Oxidative stress; Oxygen; Reactive oxygen species; Research Article; Resonance; Singlet oxygen; Sodium; Spin resonance; Stability; Surface plasmon resonance; Tumorigenesis; 元激发; 分子氧; 氧活化; 测金; 电子自旋共振; 纳米棒; 羟基自由基; 表面等离子体共振
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-016-1060-7

Gold nanostructures are among the noble metal nanomaterials being intensely studied due to their good biocompatibility, tunable localized surface plasmon resonance （SPR）, and ease of modification. These properties give gold nano- structures many potential chemical and biomedical applications. Herein, we demonstrate the critical role of oxygen activation during the decomposition of hydrogen peroxide （H202） in the presence of photoexcited gold nanorods （AuNRs） by using electron spin resonance （ESR） techniques. Upon SPR excitation, 02 is activated first, and the resulting reactive intermediates further activate H202 to produce ,OH. The reactive intermediates exhibit singlet oxygen-like （102-1ike） reactivity, indicated by 102-specific oxidation reaction, quenching behaviors, and the lack of the typical 102 ESR signal. In addition, by using the antioxidant sodium ascorbate （NaA） as an example, we show that hydroxyl radicals from H202 activation can induce much stronger NaA oxidation than that in the absence of H202. These results may have significant biomedical implications. For example, as oxidative stress levels are known to influence tumorigenesis and cancer progression, the ability to control redox status inside tumor microenvironments using noble metal nanostructures may provide new strategies for regulating the metabolism of reactive oxygen species and new approaches for cancer treatment.