This mini-review summarizes recent data obtained in the process of creation of a versatile modular platform suitable for construction of supramolecular theranostic agents. As an example, we consider multifunctional hybrid agents for imaging and elimination of cancer cells. The use of an adapter protein system barnase:barstar for producing targeted multifunctional hybrid structures on the basis of highly specific peptides and mini-antibodies as addressing modules and recombinant proteins and/or nanoparticles of different natures (quantum dots, nanogold, magnetic nanoparticles, nanodiamonds, upconverting nanophosphors, polymer nanoparticles) as agents visualizing and damaging cancer cells is described. New perspectives for the creation of selective and highly effective compounds for theranostics and personified medicine are contemplated.