Head of Platform Bioengineering & Assay Development

The Mission

Drug discovery has a translation problem: more than 95% of drugs that succeed in animal models fail in humans. We're building the alternative: human-first drug discovery, powered by organoids and AI, running on real human biology from the very first experiment.

Our platform is 87% concordant with clinical patient data - a vast improvement over the 3% translational success rate of animals. We’ve demonstrated the ability to model immunotoxicology, immunogen stimulation, and two autoimmune diseases with more on the way. Numerous pharma partners including 3 Fortune 500 companies are already using the platform. We've raised ~$30M from AIX Ventures, Marc Benioff, Jeff Dean, and Y Combinator.

With the FDA Modernization Act 3.0 and the FDA's March 2026 validation framework, the regulatory tailwinds only continue to get stronger.

The opportunity ahead of the company is generational: build the first scaled engine for generating real human biological data, and use it to fundamentally change how medicines are discovered.

As Principal Scientist, you will lead the science at our San Francisco site.

You will manage our team of scientists and research associates, set experimental strategy, and own the scientific decisions that determine where we invest our experimental effort. You will remain personally at the bench on the hardest problems.

Your first priority is scientific: deepening our understanding of how our organoid models behave across donors, conditions, and operators, building the reference data and controls that let the team interpret results with confidence, and bringing that rigor to the workflows running at the site. From that foundation, you will own assay development and maturation, technology transfer from R&D, control strategy, characterization, optimization, and readiness for routine execution on the platform.

You will also serve as the scientific lead for our external partner programs, designing them well, interpreting them rigorously, and standing behind the results with our partners.

• Lead the scientific team at our San Francisco site, including hiring, managing, and developing scientists and holding a high bar for experimental rigor and pace.

• Set scientific direction and experimental strategy for the platform, and bring competing interpretations to a clear conclusion.

• Run regular data review with the team, distinguishing biological effects from technical or process effects and driving toward the experiment that resolves the question.

• Establish high standards for experimental design, controls, documentation, reproducibility, and scientific decision-making, and hold the team to them.

• Facilitate productive scientific disagreement and reach clear conclusions quickly, without suppressing dissent or letting debate stall the work.

• Serve as the scientific lead for external partner programs, from experimental design through data delivery.

• Remain close to the bench and personally engage in difficult experimental and troubleshooting work.

• Build biological systems from first principles, taking models from concept to working, characterized assays, and deepening the ones already running.

• Own the development and maturation of biological assays and workflows intended for execution on the Parallel Bio platform.

• Translate early R&D assays into robust, repeatable, scalable experimental processes.

• Develop and execute characterization and optimization strategies for complex organoid and cell-based assays.

• Identify critical assay and process parameters and understand how they influence biological outputs.

• Design experiments that establish appropriate operating ranges, robustness, and sources of variability.

• Lead troubleshooting of complex biological and process failures using structured, hypothesis-driven experimentation.

• Define and build the framework for transferring assays and biological processes from R&D into development and ultimately routine Technical Operations.

• Define clear entry and exit criteria for each stage of assay maturation and technology transfer.

• Establish objective acceptance criteria for platform readiness, including controls, expected ranges, reproducibility requirements, and system suitability.

• Ensure transferred assays have sufficient documentation, reference data, controls, and scientific understanding to support reliable execution.

• Partner with Technical Operations to ensure new processes can be executed reproducibly by trained operators rather than only by their original developers.

• Lead or support comparability studies when assays, instruments, workflows, reagents, software, or biological inputs change.

• Develop strategies for scaling biological workflows from small exploratory experiments into higher-throughput platform processes.

• Understand and reduce variability introduced by operators, instruments, automation, reagents, donors, biological materials, and environmental…