Fig. 1.

The panel on the left shows kinetic measurements of glutathione oxidation via disulfide bond formation, showing significant increase in oxidation, measured by signals of oxidized species versus reduced species in mass spectra, after incubating with silica particles in water in dark. The panel on the right shows the mass spectra comparison measuring oxidized glutathione (GSSG) as well as the reduced species (GSH) under different conditions, (Top) incubated with mesoporous silica particles, (Middle) incubated with nonporous silica particles—500 nm in diameter, and (Bottom) without incubation with particles.