Job Description

About the Company

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're looking for fast-moving, hands-on engineers and physicists with strong fundamentals, high autonomy, and a desire to make technology that feels impossible until it works.

Organ systems perform millions of complex, regulated biochemical operations every second. Your kidneys filter over 150 L of fluid per day, reabsorb over 99% of the filtrate, and hold blood pH within a tolerance of 0.05. Every drop of blood travels a fraction of the body's ~60,000 miles of vessels, through capillaries so narrow that your ~25 trillion red blood cells must fold themselves to pass through and deliver their oxygen. At Until, we're building the technology to bring all of this to a full stop and start it again.

Understanding exactly how this machinery responds to cryopreservation takes a new toolkit: optics, photonics, chemistry, electrical engineering, and organ science. Work here runs across the entire engineering stack, from sensing physics at the tissue interface, to analog front ends and ADCs that pull faint signals out of noise, and the FPGAs that orchestrate instruments in real time. If you want to build biological sensing and actuation from scratch while opening a new window into organ dynamics, this is the role for you.

What You'd Do

• Design, build, and debug sensing hardware.
• Develop electronic instrumentation that reads faint biological signals.
• Own mixed-signal PCB design from schematic capture through layout, fab, and bring-up.
• Work with FPGAs to orchestrate the instrument in real time: acquisition timing, data streaming, and control.
• Integrate sensors, boards, firmware, and software into one instrument that runs reliably inside the organ preservation system.
• Reason from first principles, using circuit theory, optics, and measurement physics to model system behavior and debug ambiguous hardware problems.
• Build test fixtures, experimental setups, and control software for validating sensors on real organs.
• Learn quickly, own problems end to end, and contribute across the sensing stack, from transducer to data.

About You

• You have a strong command of circuit theory and measurement physics (impedance, noise, signal integrity, sampling, electromagnetics), and reach for them instinctively when hardware misbehaves.
• You can walk us through a project in depth: what you built, the physics reasoning that got you there, and where your first mental model was wrong.
• You make order-of-magnitude estimates quickly and can explain the intuition behind them.
• You’ve taken real analog and digital circuits from schematic through PCB layout and bench bring-up.
• You have experience with instrumentation, data acquisition, FPGAs or embedded systems, and object-oriented programming.
• You think in systems: interfaces, integration, and how a board behaves inside the whole instrument, not just on the bench.
• You're excited to work at the edges of your field: the instrument spans optics, photonics, chemistry, and organ science, and you'll learn what you don't know.
• You have a BS/MS in EE, Physics, or equivalent self-taught depth; we care more about demonstrated reasoning ability than credentials.
• You want to join a small, fast-paced team on an excellent adventure.

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.