Scientists at the QIMR Berghofer Medical Research Institute created models of the human blood-brain barrier, a wall of cells that protects the brain with pathogens and toxins, and successfully opened it.

The barrier works as a natural shield and blocks 98 per cent of disease-fighting drugs from entering the brain.

QIMR Berghofer scientists created blood-brain barrier models using stem cells from Alzheimer’s patients and successfully unlocked the barrier using focused ultrasound.

In a remarkable breakthrough, the scientists opened the barrier to drugs that can combat Alzheimer’s disease.

“It’s a major breakthrough in terms of understanding the way that we can deliver drugs to the brain,” group leader Professor Anthony White said.

“We’re really on the cusp of being able to make some kind of difference in people with Alzheimer’s disease.”

Stem cell researcher Dr Lotta Oikari said the results were very consistent and researchers were able to replicate the experiment a number of times.

She said the model can potentially identify previously tested drugs that might have failed and attempt to deliver them more efficiently with the new method.

Fellow researcher Joanna Wasielewska hoped the research would be a therapeutic breakthrough for Alzheimer’s patients.

“The very first clinical trials show its safety in human patients,” she said.

“We are really at this last step of breaking the ultrasound-mediated drug delivery to patients suffering from brain disorders.”

Researchers are already working on developing models for motor neurone disease and childhood dementia.