From serendipity to startup: the story behind SBMatrices
What began as an accidental discovery in a chemistry lab has evolved into a deeptech venture with the potential to significantly impact organoid research and regenerative medicine. SBMatrices, a spin-off from Radboud University, is developing Fybrix—a synthetic, animal-free alternative to Matrigel, the current gold standard for 3D cell culture.
Matrigel, a biomaterial derived from mouse tumors, has an ill-defined composition, it is expensive, poorly reproducible, and difficult to scale. Despite its widespread use, its animal and cancerous origin present ethical and scientific limitations that hinder progress, particularly in clinical translation. By combining innovative chemistry with biological insight, SBMatrices offers a next- generation solution: Fybrix is reproducible, defined, and biocompatible. Early results suggest it even accelerates organoid growth and differentiation.
At the heart of SBMatrices are scientist and founder Dr. Paul Kouwer and entrepreneur-CEO Sander Claus. Together, they share their journey of transforming a promising lab material towards market-ready product—that could help shape the future of personalized and regenerative medicine.
AN ACCIDENTAL BREAKTHROUGH
The lab originally worked on electrooptical polymers. Paul explains: “In a project for anticounterfeit applications, to secure bank- notes, we tried to design water-soluble poly- mers. Instead, we unexpectedly ended up with a gel.That alone was intriguing, but what truly caught our attention was that the gelation occurred upon heating—not on cooling like gelatin deserts—and that the gels formed a fibrous network, just like collagen. That’s when we started to consider potential biological applications.”
Though Paul’s team had no prior experience in cell biology, help was closer than expected: right across the street at the Radboudumc. “They were immediately intrigued and began testing it with fibroblasts, stem cells and other primary cells and cell lines.” says Paul.
Paul continues: “But the early experiments lacked structure. We couldn’t draw solid conclusions. So, I brought the biology in-house. I expanded my research group with biologists, who worked closely with the hospital researchers. That changed everything. We started validating the material in more structured ways—with stem cells, for instance, which are highly sensitive to their environment.
By adjusting the gel material, we could steer cell behavior. We built up increasing fundamental knowledge on cell-matrix interactions, and at the same time worked on applied themes, such as fibrosis. Now, we also work increasingly on the expansion and application of organoids.”
FROM GEL TO COMPANY
The commercial potential of the material became apparent early on, but an early commercialization attempt with an external partner failed because of a poor match of the team and the market approach. At the same time, in labs at Radboud University, Radboudumc and at close collaborators, exciting biological results came in and momentum grew, resulting in researchers from outside Radboud or the Netherlands requesting samples. Paul occasionally asked his PhD students to produce extra batches to meet this demand, but they began to push back.
“One of them eventually said: ‘Paul, I’m not a sample machine.’ And she was right. We couldn’t keep handling this informally within the university. Paul said. That realization marked a turning point. Paul decided to professionalize the effort and applied for a NWO Demonstrator grant. With that support, the team successfully scaled production from a typical 100 milligrams to standard 10-gram batches—enough to make liters of gel.
Paul: ”Currently, we focus on organoid culture as beachhead market; commercially viable alternatives to Matrigel are simply unavailable, plus demand is large and rapidly growing. On top of that, together with partners from industry and academia (including Hans Clevers, one of the founding fathers of organoid technology), we have excellent results that even outcompete Matrigel.”
BUILDING THE TEAM
Initially, Paul teamed up with one of his PhD students to explore commercialization through the Venture Challenge. The plan was for her to become CEO—but ultimately, entrepreneurship wasn’t the right fit. “And I didn’t want to be CEO either, I’m a scientist. I love the science. When I’m asked a question, I always think from the content first. I needed a partner who could think strategically and commercially. Someone who can say: ‘Yes, the science is strong—but how does this fit into a bigger picture?” Paul said.
Mid 2023, Paul began searching for a business co-founder. Through regional development agency Oost NL, he met Sander Claus—an experienced entrepreneur with a track record in business development, albeit outside of life sciences. Paul: “At first, I had no idea what I was getting into.” Sander admits. “The sector was completely new to me. I had to learn a new terminology almost daily—thank goodness for ChatGPT—and programs like unlock_ in Leiden and the TTT initiative from RegMed XB were incredibly helpful.”
Over time, the product began to take shape in his mind. “Writing the business plan helped me understand the opportunity. We’re preparing for seed financing now and planning our market entry.”
THE ROLE OF TTT AND THE VOUCHER
A voucher from the TTT program gave Sander the space to explore the technology’s market potential.
Sander: “I’ve been an entrepreneur for decades and am used to taking risks, but this sector was so new that I didn’t have a framework to assess the opportunity. The voucher gave me time to dive deep and assess the risks and potential. I discovered that there was strong interest and a credible business case. Paul’s passion and our personal connection ultimately convinced me to join as CEO.”
Paul adds: “We used part of the voucher to prepare the material for clinical applications, aligning with GMP standards. The funding wasn’t huge, but it was strategically important. It forced us to think ahead—about long-term strategy, compliance, and product readiness.”
DRIVEN BY PURPOSE
Both founders are motivated by a deep sense of purpose. Paul is clear: “My life would have been easier without starting a company, but I believe in this material. It has scientific, commercial and most importantly, it has massive societal value. I see absolutely no reason to keep using animal-derived materials for 3D cell culture. This product needs to be on the market.”
Sander agrees: “It’s simply too valuable to leave on the shelf. Initially, I struggled to grasp the product’s full impact—I don’t have a biotech background. First, I understood we were offering an alternative to animal-based testing and production but only later, I realized the proposition goes much further: we are also enabling true progress in personalized and regenerative medicine.”
PREPARING FOR LAUNCH
The team is preparing for market entry, but with careful timing.“While we’re working on the license to be finalized and start sales, we are already engaging with end users”. Paul says.
Paul continues: “We want to talk to as many Matrigel users as possible. We need to understand their pains and itches. During the Venture Challenge, we interviewed many people and realized their priorities vary. If you ask what users think of Matrigel, you’ll get a long list of drawbacks— with high costs and poor reproducibility usually on top. But when you dig deeper, only one or two of the disadvantages are real showstoppers, and they differ per lab.
That’s what makes it both complicated and exciting. We need to ask the right questions: What exactly do you need? What’s the real problem? Then we can deliver targeted solutions. At the same time, we’re already seeing users needing support. That means we need capacity—for both onboarding and continued optimization. We’ll need both chemists and biologists, and of course, additional funding.
Sander adds: “We’re having discussions with Oost NL and targeting research institutes first. Pharma companies may be slower and more cautious, but it’s important to engage them early. We want to host hands-on trainings and foster collaborations, and we aim to start an early user community to encourage knowledge sharing. Every day, researchers make discoveries that we need we to share in order to build and expand the knowledge base of Fybrix.”
LOOKING AHEAD
For now, SBMatrices operates from the Huygens building at Radboud University—that offers facilities supported by the province to help startups access lab infrastructure. “It’s exactly what we need at this stage,” Sander says.
Paul is optimistic: “Initially, I thought I’d stay in academia and support the spin-off from a distance but realized that to make it work, I need to be fully involved. Fortunately, we’ve been able to strike a good balance with Radboud University. They’re mindful of potential conflicts of interest, but the collaboration has been smooth. It helps that we’re in such an entrepreneurial environment.”
The team recently defended their application for the NWO Take-Off Phase 2 grant and is actively exploring additional funding. A €1–2 million seed round is underway, aimed at team building, market development, and technical optimization—including sterilization protocols.
Paul reflects on what it means to commercialize academic work: “It doesn’t feel strange. Many of my colleagues are founding companies. But my motivation is very specific: I believe this product is valuable. It belongs in the hands of researchers, developers, and clinicians. That’s what drives me.”
Are you currently working with Matrigel—or looking for a synthetic, animal-free alternative? Paul and Sander would love to hear from you. Your insights, feedback, and use cases can help shape the future of Fybrix. Reach out to explore collaboration, request a sample, or share your thoughts.
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