Erydel proprietary method is based on the unique properties of the erythrocytes to be reversibly opened under hypotonic conditions without losing their functionalities. The temporary opening of pores on the red cell membrane allows small molecule, peptides, proteins, nucleic acids, dyes, nanoparticles, etc., to be encapsulated. Pores open when erythrocytes are placed in a hypotonic environment. Once normal osmosis has been restored and drug excess has been removed, pores are then re-sealed. The loaded erythrocytes, infused to a patient, act as drug or diagnostic carrier besides maintaining their physiological properties.