Senior Scientist, Cardiac Preservation (Organ Perfusion)

Until is a moonshot company building a "pause button" for biology. Our near-term focus is organ-scale reversible cryopreservation: preserving donated organs at subzero temperatures without ice formation, then rewarming them uniformly for transplant. By solving this grand challenge, we're laying the foundation for whole-body reversible cryopreservation, giving patients a bridge to future cures. To achieve our goal, we are assembling an interdisciplinary team to develop perfusion systems, cryoprotectant formulations, and vitrification and rewarming hardware. We envision a future where no transplantable organ is lost to logistics, and no terminal diagnosis is final because patients can safely wait for future medicine to arrive. About the Role We are seeking a Senior Scientist, Cardiac Preservation to lead our heart preservation efforts within the whole organ preservation team. You will own a large domain and play a vital role in shaping how Until preserves, recovers, and assesses the viability of the heart through cryopreservation. Drawing on deep expertise in cardiac physiology and ex vivo heart perfusion, you will design and execute the experiments that make reversible cryopreservation of the heart a reality. You will collaborate with scientists and engineers across the company on approaches grounded in the first principles of biology, physics, and chemistry. Creative and highly independent scientific engagement is a requirement of the role, and new avenues for discovery and optimization are continuously supported. What You'd Do: • Develop and execute ex vivo heart perfusion protocols, including normothermic machine perfusion (NMP), to maintain and evaluate cardiac viability before and after cryopreservation. • Build out the heart viability assessment toolkit, including contractile and hemodynamic function, perfusion metrics, metabolic and lactate profiling, histology, and omics. • Propose and test adjustments to cryoprotectant formulations, loading/unloading, cooling, and rewarming protocols to optimize cardiac health and recovery. • Translate detailed knowledge of cardiac physiology and biology into experimental design and interpretation across the team. About You: • Deep, hands-on expertise in ex vivo heart perfusion, ideally including normothermic machine perfusion (NMP) of the heart. • Intimate understanding of cardiac physiology and biology, including myocardial metabolism, contractile function, and ischemia/reperfusion injury. • Experience designing and running organ viability assessments and interpreting multimodal readouts (functional, metabolic, histological, omics). • Comfort working at the bench in an ex vivo model and a track record of executing complex experimental protocols. • Demonstrated success working through hard, open-ended problems, with a passion for rapid problem solving and rapid exploration of unfamiliar topics and protocols. • Ability to think from first principles and tackle complex, cross-disciplinary problems alongside other scientists and engineers. Preferred Qualifications: • PhD in a STEM field, ideally in cardiac physiology, organ preservation, or transplant — or significant (4+ years) experience as a scientific leader in an industry context. • Direct experience with cardiac transplant or heart preservation research.