Measuring just four millimetres across, the tiny “organoids” could lead to new treatments for neurological and mental diseases.
Stem cell scientists have grown a miniaturised “brain-in-a-bottle” which they hope will lead to treatments for neurological and mental diseases.
The tiny hollow “organoids”, measuring three to four millimetres across, have a structure similar to that of an immature human brain including defined regions.
But the scientists insist they are still a long way from building a working artificial brain – or even replacement parts for damaged brains.
The goal was to produce a biological tool that can be used to investigate the workings of the brain, better understand brain diseases and test out new drugs.
One expert said the “audacious” discovery could lead to the future creation of a simple animal-like brain that could be linked to sense organs and had the ability to learn.
Other laboratory “models” of human organs have previously been grown from stem cells, including those replicating the liver, intestine, pituitary gland and eye.
The key to the new research involved nourishing immature cells in a gel-like “matrix” that allowed the complex organoid structures to develop.
These were then transferred to a spinning bioreactor which provided extra nutrients and oxygen, enabling them to grow much larger in size.
After two months of development the “mini-brains” had become globular spheres up to four millimetres in diameter. Each one mimicked the layered structure of a human brain growing within a developing foetus.
Among the identifiable regions were a cerebral cortex, forebrain, choroid plexus – the body that produces cerebro-spinal fluid – and even a rudimentary retina.
In a further experiment to show the technique’s potential, the researchers used cells taken from a patient with the brain disease microcephaly to create the mini-brains.
They found that the organoids’ growth was stunted, mimicking the disease which causes the brain to be much smaller than normal.
Professor Juergen Knoblich, from the Institute of Molecular Biotechnology in Vienna, said: “We’ve been able to model one disease which is microcephaly.
“But ultimately we’d like to move to more common disorders like schizophrenia or autism. We are confident that we might be able to model some of these defects.”
He said the extreme complexity and inter-connectivity of the adult brain made him “pessimistic” about the possibility of replacing whole brain structures with laboratory-grown versions.
Stem cell scientist Dr Zameel Cader, from Oxford University and the John Radcliffe Hospital, described the research as “fascinating and exciting”.
He added: “The structure they have generated is a long way from a real brain and the challenges for creating even a primitive foetal brain remain daunting.
“The proper organisation and blood supply of the brain are not present in this model and are major limitations.
“However, their model is audacious and the similarities with some of the features of a human brain are really quite astounding.”