Stem cells could be inhaled to treat neurological conditions (Image: Hans Neleman / Stone / Getty)

STEM cells show promise for treating a range of neurological conditions, including Parkinson’s, strokes and Alzheimer’s, but it is tricky getting them into the brain. Perhaps inhaling stem cells might be the answer – if mice are anything to go by.

Other options all have their drawbacks. Drilling through the skull and injecting the stem cells is painful and carries some risks. You can also inject them into the bloodstream but only a fraction reach their target due to the blood-brain barrier.

The nose, …