Red blood cell-derived vesicles (RDV) as a nanoparticle drug delivery system. The RDV are smaller than one micrometer, capable of encapsulating and delivering an exogenous substance into cells. The substance may be at least one selected from the group consisting of fluorophores, nucleic acids, superparamagnetic compounds and therapeutic agents. The RDV are capable of delivering encapsulated substances into cells including stem cells. The delivered substance within the cell or stem cell may be traced or tracked using a suitable device either in vitro or in vivo.
