But without help, the large enzyme can’t make it through the protective barrier that separates the blood from one of the most important organs — the brain. For Gordon’s children, that help comes from an innovative molecular transport system, a chemical tag attached to IDS that shuttles it through the tightly joined cells that make up the blood–brain barrier. Several such shuttles, which take advantage of natural transport systems in the brain, are now being developed. And that’s not just for rare diseases such as Hunter syndrome, but also for cancer, Alzheimer’s disease and other common brain disorders. ‘It seems like every major company in this space has a programme to develop brain shuttles,’ he says.”From Nature.