Metal nanoparticles are reported to be toxic due to the generation of free radicals at their surface. Relatively inert thiol-capped gold nanoparticles (AuNPs) have been reported to induce radical formation in the presence of hydroperoxides, which would conflict with their potential use as inert scaffolds for the design of novel nano-antioxidants. With the aim of clarifying this aspect, we investigated the pro-oxidant activity of dodecanethiol-capped AuNPs (∼5 nm diameter), prepared through the Brust–Schiffrin synthesis, by oxygen-uptake kinetic studies. The pro-oxidant activity was found to be proportional to the impurities of the transfer agent tetraoctylammonium bromide (TOAB) left from the synthesis and decreased on repeated washing of the nanoparticles. Under identical settings similar batches of AuNP (∼9 nm diameter) prepared through the Ulman method without onium salts showed no pro-oxidant behavior. The alternative onium phase-transfer agents Oct4NBF4 (Oct=octyl), Hex4NBF4 (Hex=hexyl), and Hex4NPF6 were comparatively investigated and showed lower pro-oxidant activity depending on the counterion (Br−>PF6−>BF4−).

Baschieri, A., Del Secco, B., Zaccheroni, N., Valgimigli, L., Amorati, R. (2018). The Role of Onium Salts in the Pro-Oxidant Effect of Gold Nanoparticles in Lipophilic Environments. CHEMISTRY-A EUROPEAN JOURNAL, 24(36), 9113-9119 [10.1002/chem.201801110].

The Role of Onium Salts in the Pro-Oxidant Effect of Gold Nanoparticles in Lipophilic Environments

Baschieri, Andrea;Del Secco, Benedetta;Zaccheroni, Nelsi
;
Valgimigli, Luca
;
Amorati, Riccardo
2018

Abstract

Metal nanoparticles are reported to be toxic due to the generation of free radicals at their surface. Relatively inert thiol-capped gold nanoparticles (AuNPs) have been reported to induce radical formation in the presence of hydroperoxides, which would conflict with their potential use as inert scaffolds for the design of novel nano-antioxidants. With the aim of clarifying this aspect, we investigated the pro-oxidant activity of dodecanethiol-capped AuNPs (∼5 nm diameter), prepared through the Brust–Schiffrin synthesis, by oxygen-uptake kinetic studies. The pro-oxidant activity was found to be proportional to the impurities of the transfer agent tetraoctylammonium bromide (TOAB) left from the synthesis and decreased on repeated washing of the nanoparticles. Under identical settings similar batches of AuNP (∼9 nm diameter) prepared through the Ulman method without onium salts showed no pro-oxidant behavior. The alternative onium phase-transfer agents Oct4NBF4 (Oct=octyl), Hex4NBF4 (Hex=hexyl), and Hex4NPF6 were comparatively investigated and showed lower pro-oxidant activity depending on the counterion (Br−>PF6−>BF4−).
2018
Baschieri, A., Del Secco, B., Zaccheroni, N., Valgimigli, L., Amorati, R. (2018). The Role of Onium Salts in the Pro-Oxidant Effect of Gold Nanoparticles in Lipophilic Environments. CHEMISTRY-A EUROPEAN JOURNAL, 24(36), 9113-9119 [10.1002/chem.201801110].
Baschieri, Andrea; Del Secco, Benedetta; Zaccheroni, Nelsi*; Valgimigli, Luca; Amorati, Riccardo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/659441
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