Silver Sub-nanoclusters Electrocatalyze Ethanol Oxidation and Provide Protection against Ethanol Toxicity in Cultured Mammalian Cells

摘要

Abstract: Silver atomic quantum clusters (AgAQCs), with two or three silver atoms, show electrocatalyticnactivities that are not found in nanoparticles or in bulk silver. AgAQCs supported on glassy carbon electrodesnoxidize ethanol and other alcohols in macroscopic electrochemical cells in acidic and basic media. Thisnelectrocatalysis occurs at very low potentials (from ∼ 200 mV vs RHE), at physiological pH, and at ethanolnconcentrations that are found in alcoholic patients. When mammalian cells are co-exposed to ethanol andnAgAQCs, alcohol-induced alterations such as rounded cell morphology, disorganization of the actinncytoskeleton, and activation of caspase-3 are all prevented. This cytoprotective effect of AgAQCs is alsonobserved in primary cultures of newborn rat astrocytes exposed to ethanol, which is a cellular model ofnfetal alcohol syndrome. AgAQCs oxidize ethanol from the culture medium only when ethanol and AgAQCsnare added to cells simultaneously, which suggests that cytoprotection by AgAQCs is provided by the ethanolnelectro-oxidation meditated by the combined action of AgAQCs and cells. Overall, these findings not onlynshow that AgAQCs are efficient electrocatalysts at physiological pH and prevent ethanol toxicity in culturednmammalian cells, but also suggest that AgAQCs could be used to modify redox reactions and in this waynpromote or inhibit biological reactions.