Tag Archives: California Institute for Regenerative Medicine (CIRM)

First fully synthetic brain tissue model could enable more reliable animal-free drug testing

A November 17, 2025 University of California at Riverside (UCR) news release (also on EurekAlert) by Jules Bernstein announced some encouraging news for those who would like to see the end of animal testing, Note: Links have been removed,

For the first time, scientists have grown functional, brain-like tissue without using any animal-derived materials or added biological coatings. The development opens the door to more controlled and humane neurological drug testing.

Neural tissue engineering’s overall goal is to create something that closely resembles the structure and function of the human brain, enabling more reproducible neurological disease studies and drug testing.

“One of the drawbacks of most brain tissue platforms is that they utilize biological coatings to help living cells thrive. These animal-derived coatings are poorly defined, which makes it difficult to recreate their exact composition for reliable testing,” said Iman Noshadi, a UCR associate professor of bioengineering who led the team.

In addition, using animal brains to conduct research relevant to human conditions — as is currently the norm — is not ideal. There are significant genetic and physiological differences between rodent and human brains. This platform could reduce, and in some cases eliminate, the need to use animal brains for this purpose and aligns with U.S. FDA efforts to phase out animal testing requirements in drug development.

The new material, described in the Advanced Functional Materials journal, functions as a scaffold on which to grow donor brain cells and could be used to model traumatic brain injuries, strokes, or neurological diseases like Alzheimer’s.

It is primarily composed of a common polymer known for its chemical neutrality called polyethylene glycol, or PEG. Typically, living cells do not attach to PEG without the addition of proteins like laminin or fibrin.

By reshaping PEG into a maze of textured, interconnected pores, the research team turned an inert material into a matrix that cells recognize, colonize, and use to build functional neural networks. Once these cells mature, they could exhibit donor-specific neural activity, allowing direct evaluation of drugs targeted to their neurological conditions.

“Since the engineered scaffold is stable, it permits longer-term studies,” said Prince David Okoro, the study’s lead author and a doctoral candidate in Noshadi’s lab. “That’s especially important as mature brain cells are more reflective of real tissue function when investigating relevant diseases or traumas.”

To build the scaffold structure, the team used a process involving water, ethanol, and PEG flowing through nested glass capillaries. When the mixture reached an outer water stream, its components began to separate. A flash of light stabilized this separation, locking in the porous structure.

The pores allow oxygen and nutrients to circulate throughout the structure efficiently, essentially feeding the donated stem cells.  

“The material ensures cells get what they need to grow, organize, and communicate with each other in brain-like clusters,” Noshadi said. “Because the structure more closely mimics biology, we can start to design tissue models with much finer control over how cells behave.”

The research began in 2020 and was supported by Noshadi’s startup funds from UC Riverside. Okoro’s work was funded by the California Institute for Regenerative Medicine.

Currently, the scaffold material is only about two millimeters wide. Going forward, the team is working to scale the model and has submitted a related paper focused on liver tissue.

The group’s long-term goal is to develop a suite of interconnected organ-level cultures that reflect how systems in the body interact. They hope these tissue platforms will offer stability, longevity, and functionality comparable to the brain tissue model.

“An interconnected system would let us see how different tissues respond to the same treatment and how a problem in one organ may influence another. It is a step toward understanding human biology and disease in a more integrated way,” Noshadi said.

Here’s a link to and a citation for the paper,

Bicontinuous Microarchitected Scaffolds Provide Topographic Cues That Govern Neuronal Behavior and Maturation by Prince D. Okoro, Kevin Dalsania, Shiril B. Iragavarapu, Benjamin Dela Cruz, Aihik Banerjee, Merve Basaranbilek, Martin F. Haase, Bahman Anvari, Iman Noshadi. Advanced Functional Materials Volume 36, Issue 5, 15 January 2026 e09452 First published online: 01 October 2025 DOI: https://doi.org/10.1002/adfm.202509452

This paper is open access.

Need to improve oversight on chimeric human-animal research

It seems chimeras are of more interest these days. In all likelihood that has something to do with the fellow who received a transplant of a pig’s heart in January 2022 (he died in March 2022).

For those who aren’t familiar with the term, a chimera is an entity with two different DNA (deoxyribonucleic acid) identities. In short, if you get a DNA sample from the heart, it’s different from a DNA sample obtained from a cheek swab. This contrasts with a hybrid such as a mule (donkey/horse) whose DNA samples show a consisted identity throughout its body.

A December 12, 2022 The Hastings Center news release (also on EurekAlert) announces a special report,

A new report on the ethics of crossing species boundaries by inserting human cells into nonhuman animals – research surrounded by debate – makes recommendations clarifying the ethical issues and calling for improved oversight of this work.

The report, “Creating Chimeric Animals — Seeking Clarity On Ethics and Oversight,” was developed by an interdisciplinary team, with funding from the National Institutes of Health. Principal investigators are Josephine Johnston and Karen Maschke, research scholars at The Hastings Center, and Insoo Hyun, director of the Center for Life Sciences and Public Learning at the Museum of Life Sciences in Boston, formerly of Case Western Reserve University.

Advances in human stem cell science and gene editing enable scientists to insert human cells more extensively and precisely into nonhuman animals, creating “chimeric” animals, embryos, and other organisms that contain a mix of human and nonhuman cells.

Many people hope that this research will yield enormous benefits, including better models of human disease, inexpensive sources of human eggs and embryos for research, and sources of tissues and organs suitable for transplantation into humans. 

But there are ethical concerns about this type of research, which raise questions such as whether the moral status of nonhuman animals is altered by the insertion of human stem cells, whether these studies should be subject to additional prohibitions or oversight, and whether this kind of research should be done at all.

The report found that:

Animal welfare is a primary ethical issue and should be a focus of ethical and policy analysis as well as the governance and oversight of chimeric research.

Chimeric studies raise the possibility of unique or novel harms resulting from the insertion and development of human stem cells in nonhuman animals, particularly when those cells develop in the brain or central nervous system.

Oversight and governance of chimeric research are siloed, and public communication is minimal. Public communication should be improved, communication between the different committees involved in oversight at each institution should be enhanced, and a national mechanism created for those involved in oversight of these studies. 

Scientists, journalists, bioethicists, and others writing about chimeric research should use precise and accessible language that clarifies rather than obscures the ethical issues at stake. The terms “chimera,” which in Greek mythology refers to a fire-breathing monster, and “humanization” are examples of ethically laden, or overly broad language to be avoided.

The Research Team

The Hastings Center

• Josephine Johnston
• Karen J. Maschke
• Carolyn P. Neuhaus
• Margaret M. Matthews
• Isabel Bolo

Case Western Reserve University
• Insoo Hyun (now at Museum of Science, Boston)
• Patricia Marshall
• Kaitlynn P. Craig

The Work Group

• Kara Drolet, Oregon Health & Science University
• Henry T. Greely, Stanford University
• Lori R. Hill, MD Anderson Cancer Center
• Amy Hinterberger, King’s College London
• Elisa A. Hurley, Public Responsibility in Medicine and Research
• Robert Kesterson, University of Alabama at Birmingham
• Jonathan Kimmelman, McGill University
• Nancy M. P. King, Wake Forest University School of Medicine
• Geoffrey Lomax, California Institute for Regenerative Medicine
• Melissa J. Lopes, Harvard University Embryonic Stem Cell Research Oversight Committee
• P. Pearl O’Rourke, Harvard Medical School
• Brendan Parent, NYU Grossman School of Medicine
• Steven Peckman, University of California, Los Angeles
• Monika Piotrowska, State University of New York at Albany
• May Schwarz, The Salk Institute for Biological Studies
• Jeff Sebo, New York University
• Chris Stodgell, University of Rochester
• Robert Streiffer, University of Wisconsin-Madison
• Lorenz Studer, Memorial Sloan Kettering Cancer Center
• Amy Wilkerson, The Rockefeller University

Here’s a link to and a citation for the report,

Creating Chimeric Animals: Seeking Clarity on Ethics and Oversight edited by Karen J. Maschke, Margaret M. Matthews, Kaitlynn P. Craig, Carolyn P. Neuhaus, Insoo Hyun, Josephine Johnston, The Hastings Center Report Volume 52, Issue S2 (Special Report), November‐December 2022 First Published: 09 December 2022

This report is open access.