Tiny capsules that can be injected into the bloodstream and perform corrective tasks, using biological microelectromechanical systems (bioMEMS), have been used to cure rats with diabetes.
A University of Illinois at Chicago researcher has created a nano-scale capsule, using pores on the surface only 7 nanometers across. This is big enough to let the insulin out, but small enough to keep antibodies from entering.

If it works, the nanopore capsules could be used to treat other diseases as well. The capsules could possibly carry dopamine to treat Parkinson’s patients, or cells that secrete blood-clotting factors for hemophiliacs.