
Co-Founder and Chief Scientific Officer of @untillabs
San Francisco, CA
Joined August 2010
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We’re building biology a pause button. Our challenge is deep across quantum physics, surgery, neuroscience, chemistry, molecular biology, machine learning, electronics, mechanics, and materials. Join us.
Huge congrats to @_marleyx, @raffi_hotter, @levchizhov and team! I first met Marley and Raffi back in Boston, and their audaciousness floored me. They are equally parts scrappy and rigorous, ambitious and pure in their motivation to help humanity. Watching them develop these ideas over the past couple of years was inspiring, and seeing the beautiful fruits of the first milestones even more so. I can’t stop staring at this ultrasound data. Exciting times ahead.
I'm excited to introduce Mark 1, Until's electromagnet for rapidly rewarming organs from cryogenic storage temperatures. We set out to scale magnetic nanoparticle warming to human-scale organs while keeping the coil losses low enough for hospital use. Mark 1 produces a 900 kHz oscillating field at up to 40 kA/m with 7 kW of coil loss in a bore compatible with human-sized organs. This intersection of field, frequency, coil volume, and efficiency makes the system a first of its kind.
For organ rewarming, we reduce the field strength to 29 kA/m and bring the losses down below 4 kW. At these settings, we have been able to rewarm a vitrified pig kidney loaded with our in-house nanoparticles at 50 C°/min while consuming a total of less than 4 kW out of the wall. At this power, the device could run off of a common single phase 208V circuit. This 50 C°/min warming rate exceeds the critical warming rate required to outrun ice formation using our in-house cryoprotectant.
Mark 1 is just one example of the significance of audacious engineers and applied physicists for progress in reversible cryopreservation. If you're excited by pushing the frontier in hardware to improve human health, join our team.
Here’s the blog post for those interested in learning more: untillabs.com/blog/rewarming
Hunter C Davis retweeted
Excited to co-found @Merge Labs!
TLDR: We’re developing a new paradigm for BCI using molecules instead of electrodes. If you’re excited about this and want to contribute in protein engineering, synbio, delivery, immunology, ultrasound, devices, neuroscience, or data/ML/AI, we’d love to hear from you.
merge.io/blog
merge.io/careers
🧵
Hunter C Davis retweeted
i always kinda viewed the use-case of cryopreservation to be like...egg freezing and cryonics
turns out organ transport is a logistical and financial nightmare. sufficiently good cryopreservation would simply solve that. and maybe even improve how organ matching is done!
Thanks @owl_posting for the great discussion! Really enjoyed the insightful questions and the opportunity to dive into the foundations and future of reversible cryopreservation.
Bringing organ-scale cryopreservation into existence (Hunter Davis, Ep #6)
owlposting.com/p/bringing-or…
(apple podcasts, spotify, and youtube links below)
This is an interview with @huntercoledavis, the CSO and co-founder (alongside @LauraDeming) of @untillabs, which you may also know by its prior name, Cradle. They are a biotech startup devoted to organ-scale cryopreservation. They raised a $58M Series A back in September 2025, and are backed by Founders Fund (especially interesting!), Lux Ventures, and others.
In this interview, we mainly talk about the engineering and scientific difficulties in the cryopreservation field, including some background details on their September 2024 progress report on neural slice rewarming, how they characterize tissue damage in their attempts to do kidney cryopreservation, the potential economics of future cryopreservation protocols, and lots more.
One of the most interesting conversations I’ve had in a long time. If any of this work seems interesting, Until Labs is actively and aggressively hiring!
Enjoy!
Timestamps:
0:00:00 – Clips
0:01:50 – Introduction
0:05:00 – Why don’t we have reversible cryopreservation today?
0:07:05 – Why is freezing necessary at all for preservation?
0:08:23 – Let’s discuss cryoprotectant agents
0:14:09 – Until Lab’s 2024 progress report on neural tissue cryopreservation
0:20:28 – How do you measure cryopreserved tissue damage?
0:22:34 – Translation across species
0:26:04 – Why was the cryopreservation storage time so short in the progress report?
0:30:47 – Nuances of loading cryoprotectants into tissue
0:37:03 – Let’s discuss rewarming
0:43:02 – What scientific problems amongst vitrification and rewarming keep you up at night?
0:45:58 – Why are there so few cryoprotectants?
0:48:11 – How can you improve rewarming capabilities?
0:53:03 – What are the experimental costs of running cryopreservation studies?
0:57:49 – What happens to the cryoprotectants and iron oxide nanoparticles after the organ has been thawed?
1:01:34 – Cryopreservation and immune response
1:03:25 – How do you filter through the cryopreservation literature
1:05:54 – How much is molecular simulation used at Until Labs?
1:10:04 – What are the (expected) economics of Until Labs?
1:14:49 – How much does cryopreservation practically solve the organ shortage problem?
1:17:04 – Synergy between xenotransplantation and cryopreservation
1:21:12 – How much will the final cryopreservation protocol likely cost?
1:21:58 – Who ends up paying for this?
1:23:28 – What was it like to raise a Series A on such an unorthodox thesis?
1:27:49 – What are common misconceptions people have about cryopreservation?
1:29:58 – The beginnings of Until Labs
1:34:07 – What expertise is hardest to recruit for?
1:39:27 – What personality type do you most value when hiring?
1:44:17 – Why work in cryopreservation as opposed to anything else?
1:46:26 – Until Lab’s competitors
1:49:30 – What would an alternative universe version of Hunter worked on?
1:51:33 – What would you do with $100M?
Hi Boston friends! @untillabs is hosting events next week at Harvard and MIT. Come hear about our progress and current projects. RSVP links below.
This is worth 30 min of your day. @jasonjoyride nailed it.
Starship launches evoke feelings akin to sports fandom, but your home team is humanity. It’s a wonderful lens into the experience of engineering at the frontier. Awe-inspiring demos remind the world why innovation is worth it.
Hunter C Davis retweeted
Can we please make more water? We have the technology to do mass scale desal and end Western water poverty forever. We don't have to fight over scraps. We don't have to dam up distant valleys. We don't have to suck the aquifers dry. We just need to end the ban on desalination.
Hunter C Davis retweeted
I wrote an Op-Ed about the government's attacks on Harvard. Please share with anybody who thinks these attacks help anybody.
prosyn.org/PhWi74r?h=KyJ1iCf…
Hunter C Davis retweeted
Academic friends: If you're a PI facing the need to let one or more trainees go because of canceled funding due to NIH or other cuts, please DM me.
Hunter C Davis retweeted
Just…wow. The sheer amount of speed & coordination to make this happen in <8mo… #genetherapy
We're hosting events at Harvard and MIT this week. Join our discussion about what we've been working on and the road ahead!
Join us at Harvard (2/18) and MIT (2/19) as we discuss our story, progress thus far, and outstanding technical challenges.
There'll be time to meet and chat with the team after the presentation and Q&A.
Harvard - lu.ma/m8nhd8mb
MIT - lu.ma/t3j680gk
I respect the dad jokes and the clever engineering in Blake’s thread in equal measure. Great visual and clear explanation of the exploited effect.
















