▎ 摘　　要

NOVELTY - Oxidized-carbon nanoparticles that are free from an exogenously-supplied functionalized solubilizing agent and form a non-settling dispersion in water at a concentration of about 1-5 mg/ml, the dispersion being stable to settling at ambient room temperature for at least seven days and exhibiting an absorbance maximum at about 220 nm, the oxidized-carbon nanoparticles containing about 9-15% carbonyl groups by X-ray photoelectron spectroscopy (XPS), and passing through a 0.22 mpipore size polyethersulfone (PES) filter membrane. USE - The oxidized-carbon nanoparticles are useful for biological polysulfide synthesis. ADVANTAGE - The The oxidized-carbon nanoparticles: are safe; and eliminates harmful free radicals and conversion of hydrogen sulfide to polysulfides to restore protein persulfidation. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) forming persulfide and/or polysulfide from hydrogen sulfide, comprising contacting cells containing hydrogen sulfide with the oxidized-carbon nanoparticles; (2) composition, comprising oxidized-carbon nanoparticles present in a persulfide-and/or polysulfide-producing dissolved or dispersed in a diluent; and (3) preparing an aqueous composition of oxidized-carbon nanoparticles, comprising (a) mixing carbon nanoparticles in an oxidizing concentrated nitric acid or fuming nitric acid alone or dissolved in concentrated sulfuric acid or fuming sulfuric acid to form an acidic reaction composition, (b) stirring the acidic reaction composition at atmospheric pressure at a temperature of about 22 degrees C and reflux for a time sufficient to form oxidized-carbon nanoparticles that contain about 9-15% carbonyl groups by X-ray photoelectron spectroscopy (XPS), (c) cooling acidic refluxed reaction composition and quenching same in an aqueous medium that also optionally includes a base to form an aqueous reacted composition, (d) dialyzing the aqueous reacted composition through a membrane with a molecular weight cut off of about 1000 Da against water for a time sufficient to remove water-soluble materials of a molecular weight of less than about 1000 Da to form an aqueous composition of oxidized-carbon nanoparticles, and (e) filtering the aqueous composition of oxidized-carbon nanoparticles through a 0.22 mpipore size polyethersulfone (PES) filter membrane to form an aqueous composition filtrate of the SOD-like oxidized-carbon nanoparticles.