Growing mini-organs in synthetic gel: A step toward animal-free research

The synthetic PIC gel discovered at Radboud University in 2013 has proven surprisingly effective for growing mini-organs. This finding comes from research led by molecular chemist Paul Kouwer: "This brings us a step closer to animal-free research."

When someone falls ill, a tissue biopsy is sometimes needed to determine the exact problem. Increasingly, researchers aim to grow these biopsies into mini-organs (organoids) in the lab, allowing them to study the tissue in detail and identify the most effective treatment.

According to Kouwer, "Matrigel—a biological gel derived from mouse tumors—is almost always used for this purpose." Millions of mice are bred and sacrificed each year to produce it. "That's clearly unacceptable," he adds, "especially when you realize that these animal-derived components actually undermine the reliability of the results."

The PIC gel, first developed at Radboud University in 2013, has now shown itself to be exceptionally well-suited for growing organoids. Kouwer explains, "That's a major difference compared to other synthetic gels. Those usually work fine for growing stem cells, but when it comes to more advanced applications—like organoids—it becomes much more difficult. We found that the process runs much more smoothly with our PIC gel."

Protein from bacteria

To optimize the PIC gel for organoid growth, Kouwer collaborated with Hans Clevers of the Hubrecht Institute in Utrecht, a pioneer of organoid technology. Clevers recently discovered that a bacterial protein helps mini-organs grow remarkably well on surfaces. "I suggested linking that protein to our gel to create more realistic three-dimensional tissues," says Kouwer. "Clevers was skeptical at first—but it worked beautifully."

The most exciting part is that this method eliminates the need for animals altogether. "We've now tested it with human organoids that were originally grown in Matrigel," Kouwer says. "The next step is to grow human organoids directly in the PIC gel, so the tissue is never exposed to any animal-derived components."

Toward patient-specific therapies

Kouwer also envisions broader applications for the gel. "Imagine a patient diagnosed with cancer," he says. "Ideally, you'd take a biopsy of the tumor, grow it in the lab, and then test which treatment works best. For example, in head and neck cancer, only about 30% of human biopsies can currently be grown successfully in Matrigel.

"Our gel is synthetic and therefore adaptable—unlike the animal-based version. The fact that organoids grow so well in our synthetic PIC gel gives us hope that we can further refine it and help many more patients."

Provided by Radboud University