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Company Description

We are a privately held, stealth-mode start-up biotechnology company developing lipid nanoparticle–based approaches to address unmet medical needs across oncology, hematology, and neuroscience.

The Role

We are seeking a strategic and technically deep mRNA DS Design Head (Sr. Scientist - Director) level to lead the design and engineering of nucleic acid drug substances powering our lipid nanoparticle (LNP) pipeline. Reporting to the CTO, this person will own the end-to-end drug substance strategy — from sequence and construct design through downstream purification — across mRNA, siRNA, and other nucleic acid modalities supporting in vivo CAR-T programs in oncology, immunology, and neurology, as well as nucleic acid designs for in vivo gene editing. This person will build and lead a small, high-caliber team and partner closely with platform, analytical, formulation, and pharmacology functions to translate molecular design into therapeutic candidates.

Roles and Responsibilities of the Position

• Lead the end-to-end design and engineering of nucleic acid drug substances across mRNA, siRNA, gRNA, pDNA, and related payloads, supporting in vivo CAR-T programs in oncology, immunology, and neurology, as well as in vivo gene editing applications. This includes CAR construct architecture (binder, hinge/transmembrane, costimulatory and signaling domains), mRNA design (UTRs, codon optimization, modified nucleotides, ORF engineering, expression kinetics), tunable or regulatable CAR designs, safety switches, multi-cistronic constructs, and integration with LNP delivery to T cells and other relevant cell types.
• Lead scFv and binder sourcing strategy, including evaluation of internal candidates, in-licensing opportunities, public and patent landscape analysis, and management of antibody discovery vendors or CRO partnerships, with attention to affinity, specificity, developability, and epitope considerations relevant to CAR contexts.
• Own end-to-end drug substance generation — from sequence identification through IVT or chemical synthesis, capping/tailing, and downstream purification — ensuring designs are scalable, manufacturable, and aligned with platform capabilities.
• Build, hire, and lead a small multidisciplinary team spanning construct design, molecular biology, and nucleic acid production; mentor team members and raise the bar for design rigor and experimental quality.
• Partner closely across functions to translate molecular design into actionable program decisions: with analytical development to define critical quality attributes and release specifications; with the LNP formulation team to co-optimize construct design with delivery (payload size, secondary structure, modification chemistry, ligand conjugation); and with R&D, in vitro and in vivo pharmacology, platform engineering, and project management to shape the broader development plan.
• Drive intellectual property strategy for novel CAR architectures, RNA designs, and gene editing constructs through invention disclosures, patent filings, and freedom-to-operate analysis.
• Support CMC documentation and regulatory interactions for novel modalities, contributing to IND-enabling activities and regulatory filings.
• Synthesize and present complex datasets and design rationales to internal leadership, the board, and external partners through well-constructed reports, slide decks, and working sessions.

Required Qualifications

• PhD in molecular biology, biochemistry, immunology, bioengineering, or a related discipline. Final level (Associate Director or Director) will be determined based on experience and scope.
• Minimum 5 years+ of nucleic acid therapeutic development experience (mRNA, siRNA, gRNA, ASO, or related modalities), with progressive leadership responsibility.
• Demonstrated CAR-T industry experience, including direct contributions to CAR construct design, optimization, or program advancement.
• Proven track record of independent design and engineering of nucleic acid therapeutics, including the judgment to select the right architecture and chemistry for the therapeutic question.
• Hands-on and strategic experience leading drug substance generation from sequence design through downstream purification, with familiarity in IVT, capping/tailing, and analytical handoffs.
• Demonstrated experience with antibody and binder evaluation, including affinity, specificity, developability, and epitope considerations relevant to CAR contexts.
• Proven leadership of cross-functional drug substance programs through preclinical milestones; experience hiring, mentoring, and scaling teams in a fast-paced biotech environment.
• Clear, concise communicator — comfortable defending design decisions in cross-functional and executive forums, and writing for both technical and non-technical audiences.

Additional Preferences

• Experience with LNP or other targeted delivery systems and ligand conjugation chemistry.
• Background in autoimmune and immunology CAR-T applications, in addition to oncology.
• Direct experience with in vivo CAR generation (vs. ex vivo manufactured CAR-T).
• Working knowledge of gene editing approaches (CRISPR-Cas9, base editing, prime editing, or related technologies) and the design considerations for in vivo applications.
• IND-enabling experience for novel nucleic acid or cell therapy modalities.
• Track record of publications, issued patents, or contributions to INDs in CAR-T, mRNA, or gene editing space.
• A bias toward proactive problem-solving and a collaborative mindset suited to a small, high-velocity team.

Location

San Diego, CA. This is an on-site position.

What We Offer

• An opportunity to work at the forefront of RNA and LNP-based therapeutic innovation
• A collaborative, science-first culture where individual contributions are visible and impactful
• Competitive compensation and benefits package, including health, dental, vision, and life insurance

401(k) with company match