Principal Scientist, Protein Engineering & Manufacturing

Exthymic•San Diego, CA

20d

About The Position

Exthymic is an early-stage deep-tech startup developing patient-specific cell-therapy manufacturing at the point of care. The Principal Scientist, Protein Engineering & Manufacturing is the technical owner of protein reagents used in the company’s consumables, determining reagent needs, whether production is performed in-house or by partners, and how reagents are produced reproducibly at product-appropriate scale and quality. Reporting to the Chief Scientific Officer, this hands-on scientific leader guides a small group of scientists and research associates and connects protein science with the company’s instrument and consumables platform. The role sets the scientific strategy for protein reagents and leads development from selection, discovery, engineering, and characterization through production, conjugation, quality control, and stability. It establishes workflows and specifications, scales robust methods to product supply, manages external discovery and manufacturing partners, mentors the team, collaborates across platform disciplines, and contributes to intellectual property.

Requirements

Ph.D. in biochemistry, protein engineering, molecular biology, immunology, or a related field, plus at least 6 years of relevant industry experience, or equivalent.
Hands-on leadership of antibody or protein engineering programs from discovery or design through characterization.
Deep experience with recombinant protein expression, purification, and analytical characterization.
Experience with bioconjugation and labeling chemistries.
Track record of taking a protein reagent or biologic from development into reproducible production, with defined specifications and quality control.
Experience managing CROs or external partners for antibody discovery, engineering, or production.
Experience guiding or mentoring scientists and research associates.
Comfort working in an early-stage startup with evolving priorities.

Nice To Haves

Experience with antibodies or protein reagents for diagnostics, cell selection, or cell-therapy applications.
Experience with protein immobilization on surfaces or biosensors.
Experience applying computational or AI-assisted protein design.
Familiarity with GMP or quality systems for reagents or biologics.

Responsibilities

Set the scientific strategy for proteins in the company’s consumables, from selection and engineering through characterization.
Drive protein discovery, engineering, and optimization programs, conducted in-house or with external partners.
Establish robust protein expression, purification, labeling, and conjugation methods and scale them to supply the product.
Define specifications and analytical methods for protein identity, purity, activity, and stability, and drive lot-to-lot consistency.
Select and direct antibody-discovery, engineering, and protein-manufacturing partners; scope work, conduct diligence, and transfer methods while protecting intellectual property.
Mentor scientists and research associates and set standards for rigorous, well-documented work.
Collaborate with surface, cell, hardware, and software teams to ensure protein reagents and assay readouts work together.
Identify inventions and contribute to disclosures and patent filings.