8 1 / 2025 // LEOPOLDINA / NEWS
“ An organoid cannot think ”
Leopoldina Member Jürgen Knoblich speaks at the Class II – Life Sciences Evening Lecture
Jürgen Knoblich ML has become known around the world for being the first person to establish a brain organoid in vitro . The mo lecular biologist , Member of the Leopoldina since 2024 , will speak about his research at a public evening lecture of the Class II – Life Sciences Symposium .
With your work on brain organoids , you have developed a completely new approach to researching the human brain . What is this all about ? Jürgen Knoblich : A major limitation in pharmaceutical and biological science is that almost all research is carried out on animals . We understand many things better about animals than humans . But our brain is not just a blown-up version of a mouse brain . During the development of our brains , processes occur which are simply not present in a mouse . In recent years , new methods have completely revo lutionised biomedical research . We can take blood stem cells from patients , carry out “ reprogramming ” and use them to produce muscle cells , individual nerve cells and even entire tissues . We have succeeded in turning these cells into “ brain organoids ” – three-dimensional tissue cultures which correspond to a foetal human brain in terms of their structure and in part their function .
These pea-sized organoids are often referred to as “ mini-brains ”. Do you think this is an appropriate term ? Knoblich : We don ’ t like this term at all , as an organoid cannot think .
Is this purely research or do you have applications in mind ? Knoblich : My laboratory only carries out basic research . But we have also patented these organoids and set up a biotech company to commercialise this model .
So you want to understand the brain and treat diseases ?
Jürgen Knoblich .
Image : Luiza Puiu
Knoblich : The main priority is to understand diseases ! For example , we have modelled tuberous sclerosis – a terrible form of epilepsy – in an organoid and discovered that a very specific precursor cell type , which only exists in humans , produces too many “ inhibitory interneurons ”.
Would my organoid look different from yours ? And can we gain insights for individualised therapies from this ? Knoblich : I do not think that we would find any differences between your organoid and mine . We can model very serious disorders , but we are not able to model different personalities or things like that .
When experiments are conducted on the human brain , even on only individual cells , people naturally question the ethics straight away ? Knoblich : First of all , research on organoids is positive in terms of ethics . Because of them we need to carry out fewer experiments on the living brain . And they are a good supplement to experiments on animals . One reason for people ’ s fear relates to exaggerated statements from researchers who may have attributed intelligence to organoids . Hans Schöler , a
Member of the Leopoldina , and I were asked by the Leopoldina to investigate these ethical issues in a working group and statement . We had extremely interesting discussions with philosophers , legal academics and neurobiologists .
What was the outcome ? Knoblich : We discussed three questions : Firstly , are organoids worth protecting ? And we came to the conclusion that no , they do not have any properties worth protecting . Secondly : Can they experience pain ? There is currently no evidence of this . And thirdly : Can organoids develop consciousness ? And the unanimous opinion is that this is not possible .
And what are the ethical limits to research with brain organoids ? Knoblich : One limit would be for example , if someone were to implant a large number of organoids into a monkey so that its brain consisted of 30 , 40 percent human cells . This would violate the Animal Welfare Act and is also outlawed by the international stem cell research community .
You were already working for the Leopoldina in the working group for “ Brain organoids – opportunities and limitations ” before you were elected to the Academy . How did this come about ? Knoblich : I am one of the few people who started working for the Leopoldina before being elected a Member . I was the first to write an article on the ethics of organoids , so Hans Schöler invited me to join the working group . I was very impressed by the breadth of discourse across different scientific fields . And then when I was elected to the Academy it was of course a great honour . I am particularly pleased because although I work in Austria , also for the Academy there , I am still German .
■ THE INTERVIEW WAS CONDUCTED BY CHRISTOPH DRÖSSER