Member of Scientific Staff
Substrate Bio
Member of Scientific Staff
Substrate Bio
Autonomous AI-driven wet labs for biological experimentation
LOCATION: King's Cross, London · PATTERN: Lab-based, full-time
We're a stealth startup in AI and bio, building infrastructure for data generation. The team is small and elite, the problems are hard, and the foundations are being laid right now. You'd help write them from the first line, with real ownership and a direct line to the founders.
This role covers the cell side of our protein characterisation work. You would keep the cell lines healthy and run the assays that show how a designed protein behaves on a living cell, week after week, to the same standard.
AI for biology has a data problem. The data that matters most doesn't exist yet, so we're building the infrastructure to produce it, with quality and traceability built in from day one.
We're in stealth and heads-down on execution. We'll share more about what we're building once you've spoken with the team.
You will run cell culture and the cell-based assays for our protein characterisation work. That means the mammalian lines the assays depend on, from thaw through routine passage to a banked and documented stock, and the weekly rhythm of seeding, treating, reading and reporting plates.
Most of it runs in 384-well plates with imaging-based or flow cytometry readouts. You will run those assays as designed, with the controls and replicates that make a curve defensible, and you will be the person who notices when a plate, a line or a reagent lot has started to drift.
Assay design and the shape of the cascade sit with the scientist who leads this work today, so you are not being asked to invent the panel. You are being asked to make it run the same way every week, to record what you did in a form the rest of the system can read, and to tighten the protocols as they settle, including moving them towards the plate formats our automation will take on.
◆ Take over routine culture and banking for the protein cell lines, working to the protocols we already run.
◆ Learn the panel end to end by running each assay alongside the scientist who owns it.
◆ Run at least one assay in the panel independently, including its controls and acceptance criteria.
◆ Revise one culture or assay protocol so that someone else could follow it without asking you.
◆ Hold the weekly assay schedule on your own and return results on the agreed turnaround.
◆ Bring one protocol to a tighter precision bar, or into a plate format ready for automation.
You are a hands-on cell biologist who takes assay variability personally. You have run the same assay often enough to tell a real effect from a bad plate, and you would rather find the cause than repeat the run.
The week has a rhythm in this job: cells to feed, plates to seed, runs to finish, numbers to return. You are happy with that, you keep records someone else can pick up, and you say early when something looks wrong rather than at the end of the week.
We do not hire people into boxes. The team is small, and early hires here end up owning work beyond the job they joined for. Nobody arrives with every part of this role. If you are strong in most of it and quick to learn the rest, we want to hear from you.
◆ Strong hands-on mammalian cell culture: adherent and suspension lines, aseptic technique, and thawing, passaging and banking to a high and consistent standard.
◆ Experience running cell-based assays end to end, including relevant controls, replicates and dose-response curves behind a reported number.
◆ Comfort with plate-based work and the arithmetic that goes with it, such as dilution series, plate maps and normalisation.
◆ Careful, traceable record-keeping that someone else can follow without asking you.
◆ A PhD in cell biology, pharmacology, immunology or a related field, or an MSc and two to three years of relevant lab experience.
◆ Reporter cell line bioassays for binding or blockade.
◆ Receptor internalisation, lysosomal trafficking or cytotoxicity assays.
◆ High-content or fluorescence imaging, and the image analysis behind it.
◆ 384-well formats, liquid handlers or other plate-based automation.
◆ Flow cytometry, for example for surface receptor quantification.
Most cell-based assay roles sit inside a discovery project. You build an assay, you answer a question with it, and the assay goes quiet. This one is closer to running an instrument. The same assays run every week against a stream of new molecules, and the number that comes out is the product.
That changes what good looks like. Precision matters more than novelty, a protocol is only finished when someone else can run it and get your answer, and every passage, plate and reagent lot is captured as structured data, because a result is only as trustworthy as the cells behind it.
Some people find that energising; some find it outside their lane. Worth knowing in advance which one you are.
This is a lab-based role at our site in King's Cross, London. The cells are in the lab, so most of your week will be too, with room for writing and analysis away from the bench. The wider team is distributed and travels, so you will work with people who are not always in the building.
We work in the open. Decisions are written down, work happens centrally rather than scattered across tools, and the week opens with a session the whole company attends. There is a quarterly offsite. Each person owns their area and makes the call inside it, and we will expect that of you early rather than late.
UK benefits are 30 days of annual leave plus public holidays, a pension with a 10% employer contribution, and top-tier Bupa private health cover. More is added as the team grows.
You will join the protein characterisation team and report to its lead. Day to day you will work with the scientist who designs the assay cascade, with the protein production and molecular characterisation scientists upstream of you, with the functional genomics team who share the cell culture suite, and with the engineers building the software and automation the lab runs on.
We are a small, elite team, and this is the first seat given entirely to the cell-based side of the work.
Our process has four stages. A short screening call about the role and the practicalities. A behavioural interview about how you work, run from the same template for every candidate, before anything technical. A technical stage with the protein characterisation team, built around real work rather than a puzzle, including time with us in person at the lab. Then references, aimed at whatever we still want to understand.
If you are not sure whether you match every line above, apply anyway. We would rather read it and decide.
We are an equal opportunity employer. We make hiring decisions on merit, scope-fit, and the strength of the working relationship we expect to build with each hire. Applications welcome from candidates of any background.
Autonomous AI-driven wet labs for biological experimentation
Substrate Bio operates AI-native data-production infrastructure for biology, connecting computational models with real-world experimentation. The company runs a network of autonomous, robotics-powered wet labs, starting in London with a second planned for San Francisco, running standardized experiments with full provenance, metadata, and quality control. Researchers access the labs via API, submitting experiment parameters and receiving structured data and metadata, while foundation models help design assay selections, cell systems, and gene panels. What sets Substrate Bio apart is its closed feedback loop, where better data improves its models and better models design better experiments. The goal is to make biological experimentation as programmable and scalable as computation itself.
Explore more opportunities at Substrate Bio