Role: Senior Scientist – Cell Line Engineering, Protein Expression & Assay Development  

Start date: Flexible  

Salary: Flexible, depending on experience 

About Scarlet Therapeutics:   

Scarlet Therapeutics is a biotechnology company developing transformative therapies. Building on more than a decade of world-renowned research in Bristol, UK, the team at Scarlet is pioneering unique technology to harness the potential of blood as medicine, positioning the company to become the global leader in the field of therapeutic red blood cells.  

We offer a fantastic working environment that is part of Science Creates, a Bristol-based deep tech ecosystem, combining specialist incubator facilities, a network of strategic partners and a dedicated venture capital fund.    

Overview 

We are seeking a highly skilled and motivated Senior Scientist to help drive Scarlet’s development of modified red blood cells for the benefit of human health and treatment of disease. The right candidate will join at an exciting time of growth for Scarlet and will be excited by the opportunity to contribute both intellectually and practically to developing next generation therapies.  As well as a proven record of scientific accomplishment, ideally they will bring specific expertise in engineering mammalian cell lines, alongside a desire to apply biological engineering principals to optimize protein expression, activity, and cellular function.  

We are looking for a candidate that will bring energy and enthusiasm for our exciting pipeline of work, who is ready to take the next step in their career and join us at a pivotal moment of expansion.  

Key Responsibilities 

• Culture, maintain, and differentiate erythroid and other mammalian cell lines, including HEK293 cells, for cellular engineering and downstream functional studies 

• Generate and characterize stable cell lines overexpressing exogenous proteins using lentiviral transduction.  

• Drive strategies to enhance protein expression and activity in engineered erythroid cell lines 

• Develop and execute biochemical assays to evaluate protein expression and activity 

• Lead the development, optimisation and validation of robust cell-based assays to evaluate protein function and biological activity in living cells  

• Design and execute experiments independently, including data analysis and interpretation 

• Responsible for documenting experimental results, reports, protocols, and presentations 

• Collaborate with cross-functional teams to support research and development goals 

Ideal Qualifications and Experience 

• PhD or equivalent experience in Molecular Biology, Cell Biology, Biochemistry, Synthetic Biology, or a related field 

• Minimum of 3 years’ experience in mammalian cell culture and hands-on experience generating and characterizing engineered cell lines 

• Proven experience characterizing and optimizing protein expression levels in mammalian cells 

• Experience with enzymatic assays and biochemical characterization techniques 

• Proven experience developing, optimizing, and troubleshooting cell-based assays to evaluate protein function and biological activity 

• Strong experimental design, troubleshooting, and analytical skills 

• Excellent communication and documentation skills 

Candidates with any of the following experience are particularly encouraged to apply: 

• Experience working with erythroid cells, or have a background in red blood cell biology 

• Have a background in synthetic biology, mammalian cell engineering, or related fields 

• Experience with lentiviral gene delivery and stable line generation.  

• An understanding of gene expression optimization strategies, including promoter selection, construct design, and transduction efficiency.  

• Strong understanding of enzyme biochemistry, protein structure-function and enzyme kinetics, with experience applying protein engineering principles to improve protein expression and activity 

• Familiarity with  translational research environments 

Role: Senior Scientist (Process Development) 

Company: Scarlet Therapeutics  

Location:  Science Creates Old Market, Midland Road, Bristol  

Application closing date: 30th November 2026 

Start date: negotiable 

Job Overview:  

We are seeking a dedicated and innovative Senior Process Development Scientist to join our dynamic team. The successful candidate will play a pivotal role in generating manufacturing processes for Scarlet’s red blood cell-based therapeutics. The role will also include the generation of novel cell lines required to produce the red blood cells.  The candidate will have a strong background in mammalian cell culture, up-stream and down-stream process development and will help drive forward our innovative red blood cell-based technology.  

 Key Responsibilities: 

• Invent, perform, develop and optimize mammalian cell culture processes for cell line generation and for the production and purification of red blood cells. 
• Development of formulations to stabilise red blood cell therapeutics 
• Ensure all process development and cell line generation work is sufficiently documented to support regulatory submissions or intellectual property requirements when appropriate and all activities are conducted in accordance with company’s quality system. 
• Implement rigorous quality controls to monitor cell lines integrity, viability and contamination risks to ensure the quality of any produced cell lines. 
• Ensure that all Equipment is properly maintained and calibrated for use and maintained in accordance with company standards.   
• Conduct risk assessments for all laboratory activities, identifying potential issues and implementing mitigation strategies to ensure product quality and safety.  
• Characterisation of donor derived erythroid cell lines using various cell biology and molecular biology techniques. 
• Help support and train other scientists and provide experienced user input into the development and improvement of such processes. 
• Stay updated on the latest advancements in mammalian cell line research and integrate new methodologies and technologies when applicable.  
• Regularly review and update laboratory SOPs (Standard Operating Procedures) to ensure alignment with appropriate quality standards.
• Generally adhere to applicable policies and procedure relating to working in the laboratory including adherence to documentation of activities in electronic laboratory notebooks 

 Key requirements: 

• Minimum of 5 years’ experience in mammalian cell culture and process development (upstream and downstream), mostly gained within a Biotechnology/Pharmaceutical setting.  
• Familiarity with laboratory scale bioreactors and downstream filtration systems. 
• Familiarity with analytical techniques related to cell culture, such as flow cytometry, ELISA, Western blotting. 
• Excellent problem-solving and analytical skills. 
• Strong verbal and written communication skills. 

 Preferred Experience: 

• Strong understanding and experience of operating to a GMP standard 
• Familiarity with high-throughput screening methods and use of automation. 
• Analysis of proteomic, lipidomic and metabolic data 
• Proficiency in molecular biology techniques such as PCR, qPCR, cloning, viral transduction and transfection. 

Scarlet Therapeutics is proud to be an Equal Opportunity Employer, committed to fostering a diverse and inclusive work environment. We believe in the power of diverse perspectives to drive our innovation and progress.  To qualify for these positions, you will need to be authorized to live and work in the UK.   

In your application, please send a CV and a covering letter stating your motivations and what you think you could bring to the role to leanne.parks@scarlet-tx.com.