Bioreactors have relied on impellers for decades, yet these mechanical mixers create shear forces that damage fragile cells such as induced pluripotent stem cells, natural killer cells, and dinoflagellates. Olivier Detournay, a cellular biologist who began his cancer immunology and coral research career, realized that the same physical principles governing Earth’s rotation could inspire a gentler mixing method.

In a conversation with host David Brühlmann, Detournay explains how a geophysics paper about planetary precession led to the SoftXS bioreactor, which rotates slowly at a fixed tilt angle and contains no internal hardware. The resulting resonance mixes liquid cultures evenly while keeping shear stress extraordinarily low. 

This article distills the key points from both podcast episodes, providing readers who missed the audio with a comprehensive overview of Detournay’s invention, scientific basis, and commercial roadmap.

A Career Bridge from Corals to Bioreactors

Early Work in Immunology and Marine Biology

Detournay earned a PhD in cellular therapy, focusing on cancer immunology. While completing that doctorate, he also participated in a side project that screened tropical corals for molecules capable of boosting immune cell activity. 

The work hinted at a valuable therapeutic resource inside coral reefs, but progress stalled once researchers discovered that coral animals were not the true producers. Instead, photosynthetic microalgae known as dinoflagellates generated the bioactive compounds.

The Dinoflagellate Roadblock

Producing dinoflagellates at scale proved nearly impossible. Static cultures kept the cells alive but yielded low biomass. Traditional stirred tanks killed them because bubbling or impeller shear ruptured the delicate membranes. 

Detournay concluded that industrially relevant production would require an entirely new mixing paradigm, one able to suspend cells and supply gases without creating destructive forces.

An Inspiration from Planetary Physics

Discovering the Precession Paper

During a literature search, Detournay encountered a geophysics article describing the complex movement of Earth’s interior magma, which is driven by the combination of rotation, gravity, and axial precession. 

The magma flows chaotically yet experiences minimal internal shear. Although most of the mathematics was beyond his biological training, several phrases stood out: steering, resonance, and low shear.

We need today a renew of the steering methods. There has been decades since we are always turning around the same principle for steering a bioproduction process to make it clear to steer a bioreactor, meaning the use of impellers.

Collaborating across Disciplines

Recognizing the potential relevance, Detournay approached the physicists behind the paper. The two groups initially struggled to communicate because biologists and fluid dynamicists use different vocabularies, but after weeks of discussion, they uncovered a path forward. 

By shrinking the planetary model to a laboratory scale, they hypothesized that a cylindrical vessel rotating at a shallow three-degree tilt could replicate the resonance effect that keeps magma well mixed without high shear.

The SoftXS Bioreactor Concept

Three Controllable Parameters

• The design is deceptively simple. It requires only a cylindrical vessel, a motor to induce rotation, and a support structure that holds the cylinder at a constant three-degree angle. 
• Three parameters define the mixing quality: tilt angle, vessel height-to-diameter ratio, and rotational speed. 
• The first two remain constant across scales, while the rotational speed decreases as volume increases.

Zero Internal Hardware

SoftXS contains no impeller, sparger, or baffles. Gas exchange occurs predominantly at the liquid surface, and resonance driven by the Coriolis effect keeps nutrients and cells uniformly distributed. 

For very high-density cultures, operators can install a microporous membrane at the base to deliver additional oxygen or carbon dioxide without generating bubbles that burst violently at the surface.

Shear Stress and Cell Viability

Standard impeller designs generate localized high-shear zones that damage fragile cells and trigger stress responses in more robust lines. In contrast, SoftXS maintains homogeneous flow at velocities to avoid these mechanical insults. 

Dinoflagellates survive and divide, IPS cells form aggregates without lysis, and NK cells retain functionality. The absence of internal parts also reduces cleaning complexity and contamination risk.

Laboratory Validation and Cell Types Tested

Olivier’s team has cultured several sensitive cell lines in the SoftXS prototype series.

• Dinoflagellates reached previously unattainable densities, unlocking the possibility of harvesting coral-derived bioactive molecules.
• Induced pluripotent stem cells grew as healthy aggregates suitable for downstream differentiation protocols.
• Natural killer cells expanded without loss of cytotoxicity, a key metric for cell therapy potency.
• Hepatic progenitor cells and other stem cell varieties showed comparable viability and proliferation to static controls while gaining the homogeneous mixing benefit.

Scaling Principles and Performance Data

Relationship between Volume and Rotational Speed

The smallest unit tested to date holds 150 mL and rotates at roughly seventy revolutions per minute. A 200-litre vessel mixes effectively at four revolutions per minute, demonstrating that required power drops sharply as scale increases. Calculations suggest that thousand-liter units would need only small, low-energy motors, reducing operational costs.

Mass Transfer Considerations

In small prototypes, surface gas exchange has been sufficient for cell lines with moderate oxygen demand. When cultures demand higher flux, the optional porous base delivers gases at microbubble sizes that dissolve before rising, maintaining the no-bubble, no-shear philosophy. 

The system has already met mass-transfer requirements without sparging for dinoflagellates, which consume large quantities of carbon dioxide.

We have to pay attention to bioproduction. We have to totally change our view of the scalability. These last 10 years, we've accumulated proof of concept working very well in term of cellular therapy, for example. Well, now let's make these proof of concept working and being accessible to the largest amount of people, of patients.

Commercial Roadmap

Four Product Generations

Cellura has mapped out a stepwise expansion from its inaugural one‑liter bench unit to full‑scale bioreactors, detailing four successive product generations and the financing strategy that will propel each stage.

1. V1 Bench model holding up to one litre. Users place it inside a standard CO₂ incubator. This first-generation unit is now entering the market.
2. V2 Bench model with built-in temperature, pH, oxygen and carbon dioxide controls, eliminating reliance on external incubators. The launch is targeted for next year.
3. V3 Pilot volume between ten and fifty liters, aimed at biotech firms and early clinical manufacturing. Planned release in two years.
4. V4 Production scale in the thousand-litre range for late-phase trials and commercial supply. The goal horizon is four years.

Funding and Partnerships

Sales revenue from V1 units will fund part of the development effort, but Detournay expects to raise additional equity and nondilutive financing because large-volume stainless steel or single-use systems require significant capital. He is actively pursuing industrial collaborations to integrate SoftXS with existing downstream platforms, accelerating adoption.

Advantages for Emerging Markets

Cell Therapy

Autologous and allogeneic cell therapies need gentle processing to preserve viability and function. Traditional stirred tanks remain a bottleneck when designers move beyond small bags and flasks. SoftXS gives therapy developers a clear scale trajectory from preclinical research to multi-litre clinical batches.

Cultivated Meat and Fish

Companies engineering slaughter-free meat rely on stem cells similar to IPS lines. Scaling to thousands of liters is essential to reach cost parity with conventional protein. Detournay believes SoftXS can provide the low-shear environment required for adipocyte and muscle cell expansion while simplifying cleaning procedures for food safety compliance.

Startup Lessons from Detournay

1. Secure sufficient capital early because bioprocess hardware development is expensive and slow.
2. Move quickly since established bioreactor manufacturers can respond fast once they see a viable concept.
3. Find complementary partners to integrate your novel mixing method into their ecosystems. For SoftXS, this could mean a media supplier, a downstream purification company or a contract manufacturer.
4. Stay curious because groundbreaking ideas sometimes originate outside your discipline. A geophysics paper about Earth’s core flows triggered the entire project.
5. Value mentors and people, not only technical innovation. Detournay credits interdisciplinary collaboration for turning theory into a market-ready prototype.

Key Takeaways for Process Scientists

• Shear-sensitive cells require entirely new mixing strategies if the industry hopes to deliver cell therapies and cultivated meat at an affordable scale.
• A slowly rotating tilted cylinder can achieve homogeneous mixing through resonance without impellers, bubbles, or high energy input.
• Scale-up is simplified because only rotational speed changes with volume. Height-to-diameter ratio and tilt angle remain constant.
• Early prototypes have successfully cultured IPS cells, NK cells, hepatic progenitors, and dinoflagellates, demonstrating broad applicability.
• Commercialization will follow a staged rollout from laboratory vessels to multi-kiloliter production systems, contingent on external funding and strategic partnerships.

Final Remarks

Olivier Detournay argues that the biomanufacturing community must rethink its mindset about scalability. Proof-of-concept therapies abound, but the industry now needs equipment that keeps costs down while maintaining cell integrity. Nature provided a blueprint through Earth’s rotational physics, and the SoftXS bioreactor translates that blueprint into a practical tool. 

If future milestones validate large-scale performance, the technology could shift the standard from impeller-dominated tanks to gentle resonance-based systems, opening the door to wider patient access and new therapeutic possibilities.

About Olivier Detournay

Olivier Detournay is a cellular biologist with a PhD in cellular therapy, who developed an early interest in bioinspiration. He’s also the Co-founder and Chief Scientific Officer of Cellura. Their work has focused particularly on the development of cellular production bioprocesses inspired by geophysical principles. A transversal entrepreneur with a strong affinity for health, Olivier Detournay sees it as intrinsically linked to the natural world surrounding us.

Connect with Olivier Detournay on LinkedIn.

David Brühlmann is a strategic advisor who helps C-level biotech leaders reduce development and manufacturing costs to make life-saving therapies accessible to more patients worldwide.

He is also a biotech technology innovation coach, technology transfer leader, and host of the Smart Biotech Scientist podcast—the go-to podcast for biotech scientists who want to master biopharma CMC development and biomanufacturing.  

Hear It From The Horse’s Mouth

Want to listen to the full interview? Go to Smart Biotech Scientist Podcast. 

Want to hear more? Do visit the podcast page and check out other episodes. 
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