TREATMENTS for debilitating brain diseases like Parkinson’s are often
thwarted because many drugs can’t get out of the blood vessels into the
surrounding brain tissue. But an implantable pump might solve the problem by
delivering drugs directly to the brain.
Unlike blood vessels throughout the body, those in the brain are lined with
densely packed cells that form a barrier between the brain and the bloodstream.
While this “blood-brain barrier” protects the brain from potentially harmful
molecules in the blood, it also blocks therapeutic drugs, so most drugs injected
intravenously are useless.
But Li Cao of Iowa State University in…


