Abstract: In some embodiments, the present disclosure pertains to methods of treating an inflammatory disease in a subject by administering a carbon material to the subject. In some embodiments, the carbon material selectively targets T cells in the subject. In some embodiments, the carbon material includes poly(ethylene glycol)-functionalized hydrophilic carbon clusters. In some embodiments, the administration of the carbon material to the subject reduces or inhibits T cell-mediated reactions in the subject. In some embodiments, the carbon material selectively targets T cells over other types of immune cells by preferential uptake into the T cells. In some embodiments, the carbon material reduces or inhibits proliferation of targeted T cells, reduces or inhibits cytokine production by targeted T cells, and reduces intracellular oxidant content in targeted T cells. In some embodiments, the present disclosure pertains to methods of modulating T cells ex-vivo by incubating the T cells with a carbon material.