System and method for loading the front line anticancer drug, doxorubicin (DOX) onto DNA-capped gold nanoparticles whose duplex DNA has been designed for specific DOX intercalation. Since each AuNP contains about 108 high affinity drug sites, this design allows for a high local DOX concentration on the particle. Drug binding was confirmed by monitoring the increase in DNA melting temperature, the shift in the plasmon resonance maximum, and the increase in the NP hydrodynamic radius as a function of [DOX]/[DNA] ratio. The feasibility of the nanoparticles as a drug delivery system was demonstrated by showing that particle-bound DOX could be transferred to a target DNA.