UCSF Scientists Invent Algae-Derived Dynamic Gel to Enable Reliable 3D Bioprinting of Complex Human Organoids

UCSF researchers invent a dynamic algae-based gel for 3D bioprinting, allowing lab-grown organs to develop with greater precision and consistency.

By: AXL Media

Published: Mar 12, 2026, 11:27 AM EDT

Source: Information for this report was sourced from University of California - San Francisco

Overcoming the Randomness of Lab-Grown Organoids

Miniature organs grown in laboratory settings, known as organoids, have long been plagued by unpredictable development patterns, often organizing themselves into different shapes every time they are cultured. This inconsistency has historically made it difficult for scientists to use them as reliable models for studying human disease or testing new pharmaceuticals. However, a team at UC San Francisco has introduced a breakthrough material that provides a more predictable foundation for cellular growth. By creating a medium that balances structural support with flexibility, the researchers have found a way to guide stem cells toward more natural and repeatable developmental outcomes.

Engineering a Womb-Like Growth Environment

The innovation involves mixing microparticles of alginate—a complex carbohydrate extracted from algae—into Matrigel, the industry-standard substance used for culturing cells. This mixture creates a material with properties similar to wet sand, which is stable enough to hold 3D-printed cells in place but soft enough to yield as those cells expand. Dr. Zev Gartner, a professor of Pharmaceutical Chemistry at UCSF, explained that the key factor is "stress relaxation," or the material's ability to loosen its grip over time. This ensures the environment gives way at the exact pace required for the living tissues to reshape and fold themselves into complex forms.

The Limitations of Traditional Bioprinting Media

Prior to this discovery, 3D bioprinting of complex, three-dimensional tissues was hindered by the physical limitations of existing gels. Standard liquid Matrigel is typically too runny to maintain the precise shapes required for printing, while its solidified form is often too rigid, pushing back against the cells and stalling their natural growth. Postdoctoral fellow Austin Graham noted that the goal was to find a material that allowed for exact cell placement without sacrificing the cells' ability to organize themselves. The new alginate-infused gel provides this "middle ground," allowing for high-precision printing that does not interfere with biological maturation.