Principal/Senior Scientist, mRNA engineering

Principal/Senior Scientist, mRNA Engineering South San Francisco NewLimit is a biotechnology company working to radically extend human healthspan. We're developing medicines to treat age-related diseases by reprogramming the epigenome, a new therapeutic mechanism to restore regenerative potential in aged and diseased cells. We leverage functional genomics, pooled perturbation screening, and machine learning models to unravel the biology of epigenetic aging and disease using experiments of unprecedented scale. Position NewLimit is seeking a Senior Scientist to drive our mRNA production and engineering efforts. This is a hands-on, lab based role focused on the synthesis, purification, and characterization of mRNA at large scales and high purities. You will serve as the technical lead for our production workflow, bridging the gap between molecular design and high quality material generation for in vivo and in vitro studies. What You'll Do As a member of our team, you will: Execute and scale end-to-end mRNA production, including template preparation, in vitro transcription (IVT), and purification (TFF, chromatography). Implement rigorous quality control assays, including direct RNA sequencing, fragment analysis, dsRNA quantitation, and residual contaminant analysis. Author and maintain detailed SOPs and batch records, ensuring all production runs meet GLP standards. Independently design and execute experiments to improve mRNA sequence potency, specificity, and manufacturing performance. Train, manage, and mentor other team members on mRNA optimization and production workflows. Requirements PhD in molecular biology, biochemistry, cell biology, or a related field or equivalent industry experience (5+ years). Deep hands-on experience with IVT and the specific challenges of scaling nucleic acid production. Proficiency with TFF and chromatography systems for the purification of large scale RNA batches. Ability to perform and interpret mRNA QC assays and troubleshoot mRNA production challenges. Strong experience in drafting technical reports and standardized protocols. Nice to Have Familiarity with Python or R for sequence analysis and secondary structure prediction. Understanding of how mRNA quality attributes impact Lipid Nanoparticle (LNP) formulation and delivery. Experience with complex plasmid design and bacterial scale-up for DNA template generation. Experience managing external contract manufacturing organizations (CMOs) Benefits NewLimit offers generous benefits to ensure our team can focus on our mission: Health, dental, and vision insurance 401(k) with company match Paid parental leave Industry-leading paid time off (PTO) — 20 days/year for all employees + holidays Meals and snacks on-site Salary Range: $155,000 to $200,000. Compensation for the role will depend on a number of factors, including a candidate's qualifications, skills, competencies, and experience. NewLimit offers a competitive benefits package, which includes a 401k, healthcare coverage, and 20 days of PTO. NewLimit