Scientist/Senior Scientist, High-Throughput Screening

Until; San Francisco (CA); On-site; USD 165,000 - 185,000; Full time

Benefits offered by this job

Medical, dental, vision insurance

Flexible time off

Equity compensation

401(k) plan

FSA benefits

Lunch and dinners provided

Learning stipend

On-site fitness center

Team social budget

Job summary

Until is seeking a Scientist/Senior Scientist, High-Throughput Screening to lead the cryoprotectant screening program. You will oversee day-to-day execution, integrate primary cells and iPSC-derived models, and advance assays to understand toxicity and viability in screening workflows.

Collaborating with assay scientists, biologists, and automation engineers, you will deliver milestones that accelerate organ-scale reversible cryopreservation research while maintaining rigorous data quality and

Qualifications

• PhD-level toxicology, pharmacology, cell biology, physiology, bioengineering, or related field.
• Experience designing, executing, and improving cell-based HTS workflows.
• Assay development using primary or iPSC-derived cells in renal, cardiac, or hepatic models.
• Develop mechanistic assays and translate results into toxicity hypotheses.
• Hands-on with plate-based assays, imaging, flow cytometry, and analytical chemistry.
• Quantitative analysis of screening data and multiple readouts.
• Able to mentor a scientific team and coordinate interdependent workflows.
• Collaborative and adaptable in a fast-paced research environment.

Responsibilities

• Coordinate the screening team's day-to-day work and plan experiments.
• Manage and improve the screening workflow from cell culture to data analysis.
• Increase throughput with automation while preserving data quality.
• Design functional assays to characterize cellular responses after exposure.
• Develop mechanism-of-action assays to identify toxicity drivers.
• Integrate renal, cardiac, and hepatic models into the pipeline.
• Analyze multiparametric datasets and communicate actionable findings.

Skills

High-throughput screening

Assay development

Cell biology

Data analysis

Education

PhD in Toxicology or related field

Tools

HPLC

LC-MS

GC-MS

Flow cytometry

Job description

Until is a moonshot company building a “pause button” for biology. Our near-term focus is organ-scale reversible cryopreservation: preserving donated organs at subzero temperatures without ice formation, then rewarming them uniformly for transplant. By solving this grand challenge, we’re laying the foundation for whole-body reversible cryopreservation, giving patients a bridge to future cures.

To achieve our goal, we are assembling an interdisciplinary team to develop perfusion systems, cryoprotectant formulations, and vitrification and rewarming hardware.

We envision a future where no transplantable organ is lost to logistics, and no terminal diagnosis is final because patients can safely wait for future medicine to arrive.

About the Role

We are seeking a Scientist/Senior Scientist, High-Throughput Screening to manage the day-to-day execution of our cryoprotectant screening program. You will be responsible for improving an established screening workflow, increasing throughput, identifying less-toxic formulations, and advancing our understanding of how cryoprotectants affect cell viability and function.

Working closely with assay scientists, biologists, and automation engineers, you will integrate primary cells and iPSC-derived models into scalable screening workflows. You will develop mechanism-of-action assays, investigate cellular mechanisms of toxicity. This role combines hands‑on experimental work, team coordination, and responsibility for delivering screening milestones that support organ-scale reversible cryopreservation.

You Will

• Coordinate the screening team’s day-to-day work, plan experiments, mentor team members, and ensure timely delivery of screening milestones.

• Manage and improve the screening workflow from cell-culture readiness and HTS assay execution through data analysis, quality control, and interpretation.

• Increase screening throughput and reproducibility in partnership with automation engineers while maintaining biological relevance and data quality.

• Design and execute functional assays to characterize cellular responses following cryoprotectant exposure.

• Develop and validate mechanism-of-action assays to identify drivers of toxicity and guide the design of less-toxic formulations.

• Improve the integration of renal, cardiac, and hepatic cell models using primary cells or iPSC-derived cells into the screening pipeline.

• Use chromatography and mass spectrometry to assess the purity of compounds used in cryoprotectant screening.

• Analyze multiparametric datasets, prioritize findings for follow-up, and communicate actionable recommendations to colleagues developing cryoprotectant formulations.

You Are

• Trained at the PhD level in Toxicology, Pharmacology, Cell Biology, Physiology, Bioengineering, Chemical Engineering, Tissue Engineering, or a related field, or bring equivalent expertise through at least four years of relevant experience managing research projects end to end.

• Experienced in independently designing, executing, and improving cell-based high-throughput screening workflows.

• Skilled in assay development using primary cells or iPSC-derived cells, with experience in at least one renal, cardiac, or hepatic model.

• Experienced in developing mechanistic assays and translating screening results into testable hypotheses about cellular toxicity.

• Comfortable working hands-on with plate-based assays, imaging, flow cytometry, and analytical chemistry methods such as HPLC, LC-MS, or GC-MS for compound purity assessment.

• Experienced in quantitative analysis of screening data, including quality control, statistical interpretation, and analysis of multiple experimental readouts.

• Able to coordinate and mentor a scientific team, manage interdependent workflows, and take responsibility for experimental execution and outcomes.

• Collaborative, receptive to diverse perspectives, and comfortable adapting priorities in a fast-paced, mission-driven research environment.

Preferred Qualifications

• Experience scaling automated screening workflows in close partnership with lab automation engineers.

• Experience integrating iPSC-derived cells or advanced 3D models into high-throughput screening pipelines.

• Experience with high-content imaging, transcriptomics, or other approaches that connect cellular phenotypes to mechanisms of toxicity.

• Proficiency in Python or R for analysis, visualization, and interpretation of complex screening datasets.

• Experience relating compound purity measurements to biological assay results.

Benefits

• Generous medical, dental and vision insurance coverage

• Flexible time off and paid holidays

• Competitive compensation package, including salary and equity

• Access to a 401(k) retirement savings plan

• FSA and commuter benefits

• Daily lunch and dinners, plus a variety of snacks

• Monthly learning stipend

• On-site fitness center

• Quarterly team social budget

$165,000 - $185,000 a year

As an equal opportunity employer, Until is committed to providing employment opportunities to all individuals. All applicants for positions at Until will be treated without regard to race, color, ethnicity, religion, sex, gender, gender identity and expression, sexual orientation, national origin, disability, age, marital status, veteran status, pregnancy, or any other basis prohibited by applicable law.