Xanthan gum could help scale up brain organoid research, Stanford study finds

Stanford University researchers have identified xanthan gum, a common food additive used to thicken and stabilize products, as a way to keep lab-grown brain organoids from fusing during growth. In a June study published in Nature Biomedical Engineering, the team screened 23 materials to see which could prevent organoids from fusing, a problem that has limited researchers to small batches and curtailed large-scale testing of brain disorders.

Organoids, three-dimensional models derived from human stem cells, imitate early brain development and are used to study conditions such as epilepsy, autism, and rare genetic disorders. But when placed in culture, organoids tend to clump and fuse, reducing usable samples. The Stanford team found xanthan gum uniquely kept organoids separate even at low concentrations, enabling researchers to scale up production to tens of thousands of organoids for experimentation.

Lead author Sergiu Pasca, a professor of psychiatry at Stanford's School of Medicine, said, “We can easily make 10,000 of them now. This, as with all of our methods, is open and freely accessible. There are already numerous labs that have implemented this technique.” The team tested 23 materials and selected xanthan gum due to its biocompatibility and relative affordability, enabling broader adoption across research labs. The researchers grew organoids in a nutrient-rich liquid for six days and then added one of the test materials. They then measured the number of remaining organoids 25 days later, finding that xanthan gum was the only material that kept the organoids from fusing together.

Xanthan gum is an emulsifier used in foods such as salad dressings to help thicken and stabilize products, and it has been linked in some contexts to digestive side effects like increased bowel movements, diarrhea and gas. Emerging data also suggest the additive could be linked to colorectal cancer risk by altering gut microbiota and inducing inflammation. Stanford researchers emphasize that the lab use of xanthan gum is separate from dietary exposure and would occur under controlled conditions in growth media. The broader goal is to generate thousands of organoids to test safety and efficacy for drugs and to better model neurological conditions.

To demonstrate how the technique could be used by other scientists, co-lead study author Genta Narazaki grew 2,400 organoids in batches and exposed each patch to one of 298 FDA-approved drugs. The team observed several instances in which drug exposure stunted organoid growth, indicating potential risks to fetal brain development and underscoring the importance of scalable models for safety testing. Pasca noted that a single researcher using this approach could produce thousands of organoids and run extensive drug screens, a capability that previously required more limited sample sizes.

The study’s authors said the method could accelerate work on conditions that arise during early brain development, including autism and Timothy syndrome—a rare disorder caused by mutations in the CACNA1C gene that can involve heart conditions, developmental delays, infections and seizures. Autism, in particular, remains a focus of research as US prevalence has risen in recent years; researchers hope that larger organoid banks will yield new insights into disease mechanisms and potential therapies.

The Nature Biomedical Engineering article describes a scalable workflow that researchers can implement to produce large numbers of cortical organoids for drug testing and disease modeling. Pasca and colleagues stressed the importance of accessible methods that can be adopted by many labs, aiming to shorten timelines from discovery to clinical guidance. “Addressing those diseases is really important, but unless you scale up, there’s no way to make a dent,” Pasca said. “That’s the goal right now.”

The findings come as organoid research continues to mature, offering a platform to study brain development and disorders without the need for human or animal experimentation. By enabling tens of thousands of organoids to be grown and tested, the study argues that researchers can more reliably model how disorders progress and how potential medications affect developing brains. The work also addresses safety questions for pregnant women and children, where drug effects on neurodevelopment are of particular concern. The team plans to continue refining the approach, expanding the repertoire of materials that can support long-term organoid viability, and applying the method to study a broader array of neuropsychiatric conditions, including epilepsy and schizophrenia, to better understand their onset and progression.