Senior / Principal Associate Scientist, Advanced Cell Engineering

Strand Therapeutics is a clinical-stage biotechnology company pioneering programmable mRNA therapeutics to unlock the full potential of genetic medicines. Strand applies its proprietary Signal Stack platform—integrating EverScript circular RNA, AmpliScript self-replicating RNA, SignalPath targeted delivery, and logic-driven SignalLock genetic circuits—to enable precise control of therapeutic activity across tissues and cell types, overcoming foundational limitations in targeting, durability, and safety. The company is advancing a pipeline focused on oncology and autoimmune disease, with lead programs including STX-001 (intratumorally delivered LNP-encapsulated self-replicating RNA expressing IL-12) and STX-003 (intravenously delivered for tumor-targeted expression, expected to enter the clinic in mid-2026). Strand has raised over $250 million and is headquartered in Boston, MA.

About the role

Strand is seeking a Senior/Principal Associate Scientist to join the mRNA Programming department and drive efforts in RNA LNP therapeutics for oncology, autoimmune diseases, and beyond. This role offers the opportunity to work in a matrix-based environment, contribute to the company’s future strategy, and collaborate with a highly productive team. The ideal candidate is passionate about scientific discovery, thrives in a dynamic setting, and enjoys tackling bold challenges while developing next-generation RNA medicines.

Responsibilities

• Design and execute in vitro immunological and cellular assays to characterize and optimize engineered primary cells.
• Develop ex vivo sample processing protocols and perform multiparameter spectral (Cytek Aurora) flow cytometry to analyze drug discovery assay readouts.
• Handle primary cells, including immune cell isolation, culture, and transfection using mRNA-encoded therapeutics.
• Design and execute immune cell assays to assess the efficacy and potential toxicity of key drug candidates.
• Employ cell-based and molecular biology assays with standard readout techniques to evaluate research material quality.
• Ensure data collection is captured in electronic laboratory notebooks and databases.
• Analyze data, summarize results in study reports, and provide regular updates at internal cross-functional meetings.

Qualifications

• B.S. or M.S. in Biological Sciences, Bioengineering, or a related discipline, with 2–3+ years of relevant experience in cell biology and/or immunology.
• 3–5+ years of experience with flow cytometry analysis, cell culture, and in-vitro experimentation with mammalian cell lines in a biotechnology, pharma, CRO, or academic setting.
• Theoretical and practical understanding of flow cytometry, including design and execution of >12 color panels.
• Strong laboratory experience with sample types such as whole blood, PBMC, cell lines, and single-cell suspensions from tissue samples.
• Experience with mammalian cell manipulation using mRNA transfection (LNPs and/or electroporation) is highly desired.
• Experience performing cell-based assays, including in vitro/ex vivo cytotoxicity assays, proliferation, and ELISA, is preferred.
• Ability to independently write, edit, and follow standard operating procedures, make detailed observations, and maintain clear records of lab work.
• Strong communication skills for presenting results and findings in cross-functional team meetings.
• Proficiency in Excel, PowerPoint, GraphPad Prism, FlowJo, and ELN/LIMS for data entry, analysis, and presentation.
• High level of integrity and adherence to strict compliance standards.

Preferred Qualifications

• Hands-on experience with mammalian cell manipulation using mRNA transfection and/or electroporation.
• Experience with cell-based assays, including in vitro/ex vivo cytotoxicity assays, proliferation, ELISA, and MSD.
• Plasmid cloning, RNA handling, IVT, transfection, and transduction of primary cells.
• Experience with gene/base editors is preferred.
• Familiarity with lab automation systems such as Hamilton liquid handlers or AssistPlus.

Benefits

• Comprehensive health, dental, and life insurance.
• Open PTO policy.
• Onsite lunch catering.
• Commuter support.
• Work/life flexibility and integration.
• Professional development opportunities in a small, collaborative team environment.

Pay

Base salary range: $84,000–$112,000 USD annually, plus bonus and equity incentives.