This invention is predicated on the present applicants' discovery that nanostructures comprising discrete regions of different composition can be used to deliver to a biological cell a desired combination of molecules in close proximity. Different molecules can be selectively bonded to discrete regions of different composition in sufficiently close physical relationship to enhance delivery or effectiveness within the cell. The preferred nanostructures are multicomponent nanorods. Important applications include delivery of missing DNA sequences for gene therapy and delivery of antigens or DNA encoding antigens for vaccination.