The H2O2 mediated oxidation of zero-valent silver nanoparticles (AgNPs) under acidic conditions (pHs 3.0, 3.5 and 4.0) is investigated here as is the associated production of hydroxyl radicals (HO�). Citrate-stabilized AgNPs initially react with H2O2 to form reactive intermediates with these species subsequently (i) reacting with an additional molecule of H2O2 to form surface-associated Ag(I) and O2�- resulting in the reduction of Ag(I) to Ag0 on the surface of citrate-stabilized AgNPs via electron charging and discharging process1-2, and (ii) decomposing with the aid of protons to produce HO�. The generation of HO� proceeds concomitantly with the oxidative dissolution of silver nanoparticles (AgNPs) and the release of Ag+, which is recognized as a critical determinant of AgNP toxicity.3 The combined generation of HO� and release of Ag+ from AgNPs under acidic conditions might be expected to synergistically affect the viability of cells and tissues. As such, the safety of topical exposure to AgNP-containing commercial products such as medicines, cosmetics and dressings which can access skin or internal organs such as the stomach warrants further investigation especially with regard to the impact of HO� generated by the AgNP-mediated decomposition of H2O2.(1) He, D.; Jones, A.M.; Garg, S.; Pham, A.N. and Waite, T.D. 2011  J. Phys. Chem. C115(13), 5461-5468(2) He, D.; Garg, S. and Waite, T.D. 2012  Langmuir28(27), 10266-10275.(3) He, D.; Dorantes-Aranda, J. and Waite, T.D. 2012  Environ. Sci. Technol.46(16), 8731-8738.

Fenton-like zerovalent silver nanoparticle-mediated hydroxyl radical production

248th National Meeting (2014)

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