Refeyn

We measure the mass of individual molecules using light, a technology called mass photometry. Our instruments provide rapid, label-free analysis of biomolecular function and structure, supporting research and biotherapeutic development. We characterize single particles like proteins and viral vectors in solution.

We offer:

• TwoMP for measuring the molecular mass of mRNA, antibodies, and other proteins.
• SamuxMP for quantifying AAV capsids.
• KaritroMP for characterizing larger viral vectors or virus-like particles. We also provide automated versions of some instruments and GMP compliance software for SamuxMP.

We use our technology to characterize:

• AAVs (capsid ratios, aggregation, integrity)
• AdVs (particle concentration, aggregation, purity)
• Antibody aggregation and characterization
• Membrane protein analytics
• mRNA integrity and formulation in LNPs
• Protein interactions
• Lentivirus populations

We were founded in 2018 as a spin-out from the University of Oxford, the same year our first prototype debuted and a paper on mass photometry was published in Science. We launched the OneMP instrument in 2019, followed by the TwoMP in 2021, and the SamuxMP and TwoMP Auto in 2022. Our KaritroMP launched in 2024. In 2024, we opened a Customer Innovation Center in Waltham, Massachusetts. We have over 600 installations worldwide. In January 2026, we were listed in The Sunday Times 100 Tech list of the UK’s fastest-growing technology companies and recognized as a Top Employer in the UK for 2026.

Our vision is to accelerate discovery through innovation. We aim to support scientific breakthroughs in basic research and improve biotherapeutic development and manufacturing.

Our core values are:

• Bold
• Caring
• Creative
• Sustainable

We have 51-200 employees. Our culture emphasizes collaboration, diversity, and a supportive, fun work environment. Our team is courageous, creative, and caring, and we’re united by a passion for accelerating discovery, basic research, drug development, and manufacturing.

We want to create an environment where every team member can thrive and contribute to our mission. We work to ensure a consistent “One Refeyn” experience for all employees, whether they are in-office, remote, or hybrid.

We offer a comprehensive benefits package that includes:

• 25 days of annual leave plus bank holidays.
• An employer-matched pension contribution of up to 7% or 401k.
• Medical, dental, vision, life, short- and long-term disability insurances, critical illness cover, and income protection.

Our parental leave benefits include:

• Up to 17 weeks of fully paid maternity, adoption, or shared parental leave.
• 4 weeks of fully paid paternity leave.
• An annual allowance for emergency childcare, with an additional Enjoy Benefits Nursery Scheme after 3 months.

We also offer one paid volunteer day per year. For professional development, we provide LinkedIn Learning access, formal training, practical learning opportunities, and regular training sessions on both hard and soft skills.

We support work-life balance with hybrid working options and flexible start/finish times. Onsite employees receive a subsidized weekly lunch, and all employees have access to free hot and cold drinks and snacks. We also organize social events and annual team-building activities. We use anonymized hiring practices.