A parasite called Toxoplasma gondii lurks inside 1 in 3 people worldwide, hiding out in the brain and other organs. Now, scientists have hijacked this microorganism to shuttle drugs into the brain — although they've yet to test the invention in humans.
Many drugs are difficult to deliver into the brain because the delicate organ is protected by a tight membrane known as the blood-brain barrier, which allows only select substances to pass out of the bloodstream and into its tissues. The barrier is especially impervious to large, water-attracting molecules, including many proteins.
