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Until Tech Stack

Reversible cryopreservation technology for organ preservation and transplantation

Biotechnology Research San Francisco , California 11–50 employees Privately Held

Until is building hardware and chemistry to make human organs viable for weeks instead of hours by reversibly freezing them without ice crystal damage. The tech stack—HPLC, GC-MS, PyTorch, qPCR, 3D printing, Fusion 360—reveals a materials-science and biotech engineering operation, not a software company. Heavy hiring in research (13 roles) and engineering (17 roles) across mid and senior levels signals active R&D scaling toward manufacturing validation.

Tech Stack 24 technologies

Core StackPython C++ PyTorch NumPy Pandas Linux AWS Gusto Lever HPLC GC-MS 3D printing Fusion 360 Aspen HYSYS SciPy Polars Matplotlib Plotly Git Bash GCP qPCR Notion Google Workspace

What Until Is Building

◆Challenges

Organ preservation without ice formation
Preserving organs at subzero temperatures
Uniform rewarming for transplant
Avoiding ice formation during cryopreservation
Organ loss due to logistics
Organ-scale reversible cryopreservation
Cryopreservation technology
Rewarming large samples
Organ preservation logistics
Scaling quality system

▲Active Projects

Develop vitrification and rewarming hardware
Develop perfusion systems
Cryoprotectant formulation development
Design cryoprotectant formulations
High-throughput cryopreservation formulation screening
Scalable qms implementation
Build n-of-1 electrical systems
Advanced in vitro model development
Cryoprotectant solution development for organ preservation
Cardiac arrest brain circuit stimulation

Hiring Activity

Steady35 roles · 10 in 30d

Department

Engineering

17

Research

13

Ops

2

HR

1

Legal

1

Manufacturing

1

Seniority

Mid

15

Senior

12

Intern

5

Lead

2

Junior

1

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About Until

Until develops reversible cryopreservation technology to extend organ viability from hours to weeks or months, eliminating logistics-driven organ loss in transplantation. The company addresses two technical problems: preventing ice crystal formation during freezing and achieving uniform rewarming at scale. Current work spans cryoprotectant formulation screening, perfusion systems design, rewarming hardware, and in vitro organ models. Founded in San Francisco with 11–50 employees, Until is hiring steadily across research, engineering, and operations roles in the United States.

HeadquartersSan Francisco , California

Company Size11–50 employees

Hiring MarketsUnited States

Frequently Asked Questions

What is Until's core technology?

Reversible cryopreservation for whole human organs. The company is developing hardware (vitrification, rewarming, perfusion systems) and chemical formulations (cryoprotectants) to preserve donated organs at subzero temperatures without ice formation, extending viability from hours to weeks or months.

What is Until's tech stack?

Materials characterization (HPLC, GC-MS, qPCR), computational modeling (Python, PyTorch, NumPy, SciPy, Pandas), CAD and design (Fusion 360, 3D printing), cloud infrastructure (AWS, GCP), and standard operations tools (Notion, Gusto, Lever).