Researchers at Stanford University have developed a method to grow thousands of identical brain organoids using xanthan gum, a common food additive, to prevent them from sticking together. This breakthrough, led by Sergiu Pasca and Sarah Heilshorn, enables large-scale testing for brain development and drug screening. The technique could advance studies on disorders like autism and schizophrenia.
For nearly a decade, the Stanford Brain Organogenesis Program has pioneered the use of stem cells to create three-dimensional brain-like structures known as human neural organoids and assembloids. Launched in 2018 under Stanford's Wu Tsai Neurosciences Institute, the program brings together experts in neuroscience, chemistry, and engineering to study neural circuits, neurodevelopmental disorders, and brain connectivity.
A major hurdle has been scaling production: organoids often fuse together, resulting in inconsistent batches. Early on, around twelve years ago, Sergiu Pasca, the program's director and Kenneth T. Norris, Jr. Professor of Psychiatry and Behavioral Sciences, could produce only a handful. "In the early days, I had eight or nine of them, and I named each of them after mythological creatures," Pasca recalled.
To address this, Pasca collaborated with materials engineer Sarah Heilshorn. Their team tested 23 biocompatible materials and found xanthan gum prevented clumping without affecting development. As detailed in a 2025 Nature Biomedical Engineering paper, this simple additive allows for uniform growth in batches. "We can easily make 10,000 of them now," Pasca said. The method is freely shared, with several labs already adopting it.
To demonstrate its value, co-lead author Genta Narazaki grew 2,400 organoids and screened them against 298 FDA-approved drugs. Several, including a breast cancer treatment, stunted growth, highlighting potential risks to developing brains—information crucial since such drugs are rarely tested on pregnant people or infants due to ethical concerns.
Pasca's team now aims to apply the technique to neuropsychiatric conditions. "Addressing those diseases is really important, but unless you scale up, there's no way to make a dent," he said. This innovation promises more precise research into brain disorders and safer drug development.