Red blood cells reach nearly every part of the body and live for about four months, which makes them a good vehicle for carrying drugs. A team led by Hidde Ploegh at MIT engineered erythroblasts, the precursors of red blood cells, to make surface proteins with an extra tag. An enzyme called sortase then turns the tag into a "sticky" hitch that any molecule with a matching tag can attach to.
In mice, red blood cells carrying the vitamin biotin survived in circulation for at least 28 days without harm. Because mature red blood cells lose their DNA, the modified cells carry no ongoing genetic risk. The work was published in the Proceedings of the National Academy of Sciences in 2014.
via Turning red blood cells into cargo ships | Science