▎ 摘　　要

NOVELTY - A composition comprising a graphitic composition comprising natural graphene, at least one nonionic surface active polymeric component and an aqueous medium, is provided. The composition is sonicated for at least one of a time and at an energy sufficient to exfoliate the graphene component and disperse graphene component within the aqueous medium. The sonicated composition is centrifuged for at least one of a time and a rotational rate to separate the dispersed graphene component from undispersed graphitic material, to obtain aqueous graphene dispersion. USE - Preparation of aqueous graphene dispersion used for biomedical applications. ADVANTAGE - The method enables preparation of stable, highly concentrated aqueous graphene dispersion with graphene nanoplatelets dimensioned to reduce cytotoxicity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) usage method of nonionic surface active polymeric component to affect dispersion of graphene in aqueous medium; (2) usage method of density gradient to separate graphene platelets, which involves providing a composition comprising a graphene source material, sonicating the composition to exfoliate the graphene component and disperse the graphene component within aqueous medium, contacting the dispersed graphene component with a fluid medium comprising a density gradient, and centrifuging the dispersed graphene component to induce a graphene buoyant density approximating a density along gradient and concentrating at least a portion of the graphene dispersion, and separating the concentrated graphene dispersion into at least one separation fraction enriched with graphene platelets of a thickness dimension; and (3) graphene composition, which comprises graphene platelets complexed with an ethylene diamine crosslinked poly(ethylene oxide)-poly(propylene oxide) block copolymer.