Compounds and methods are disclosed in which a prodrug can be delivered in an elevated oxidative state to cells by means of graphitic nanoparticles to which the prodrug is attached by a hydrophilic polymer and which have been made soluble by a hydrophilic polymer, such as PEG. The graphitic nanoparticle may be a single walled carbon nanotube (SWNT). The prodrug may be a DNA-binding metal-based drug. Exemplified is a platinum(IV) complex c,c,t-[Pt(NH3)2Cl2(OEt)(O2CCH2CH2CO2H)], which is nearly nontoxic to testicular cancer cells, but displays a significantly enhanced cytotoxicity profile when attached to the surface of amine-functionalized soluble SWNTs. An amine functionality on the hydrophilic polymer may be used to link the prodrug.