A small but historic thing happened in our portfolio this month: The Biological Computing Company (TBC) — formerly known as BBB — closed a $25M Seed round led by Primary Venture Partners, with participation from Builders VC, Refactor Capital, Wonder Ventures, E1 Ventures, Proximity, and Tusk Ventures.

But the round isn't actually the headline. The headline is what TBC has quietly become: the first company ever paid by a customer for biological compute.

Not a grant. Not a sponsored research agreement. A real commercial transaction, for compute work performed by living neurons, paid for by a customer who needed the answer.

If that sentence sounds dry, sit with it for a second. It is, in a literal sense, the beginning of a new computing substrate going to market.

What TBC Actually Does

TBC connects living neurons — yes, real biological neurons — to electrodes, then uses them as a computing substrate alongside modern AI systems. The team's first product has demonstrated a 23x retained improvement in video model efficiency: real-world data gets encoded into living neurons, the neural activity gets decoded into richer representations, and those representations map onto state-of-the-art AI architectures.

This isn't neuromorphic design. It isn't "brain-inspired" silicon. It's biology, doing the computation directly.

The premise underneath the company is one of the cleaner first-principles arguments in deep tech: the human brain delivers roughly an exaflop of computational power on about 20 watts. To get the same throughput out of NVIDIA's Blackwell, you'd need approximately 120,000 watts. Biology is a million times more energy efficient than the best silicon we've ever built. For decades, neuroscientists have tried to translate the brain's functionality into digital systems. TBC is doing the inverse — letting neurons compute on their own, and integrating the result into the AI stack.

Who Built It

The founders are Alex Ksendzovsky (CEO) and Jon Pomeraniec (COO), both neurosurgeons trained at the University of Maryland and the University of Pennsylvania. They've been working on the underlying problem together for over two decades — through medical school, surgical residencies, and research roles — before founding the company in 2021 after a research breakthrough in the brain's computational capabilities.

There's a reason this company exists, and why now. You needed two people with this exact pairing of clinical neurosurgical experience and a long obsession with computation to even attempt it. Alex and Jon are, as Primary's Brian Schechter put it well, founders who are brilliant, on a mission, and wildly different.

Why This Matters for Hard Tech and Deep Tech

For most of the history of computing, "compute" has meant silicon. The entire stack — chips, datacenters, the AI infrastructure boom of the last few years — has been a story about getting more out of transistors.

But there are problems silicon is not the right tool for. Some of them, like the energy and efficiency demands of frontier AI models, are becoming more acute every quarter. The cost of training is going up. The power draw is going up. The thermal load on datacenters is going up. Something has to give.

Biological compute is one of the more credible answers to that pressure. It sits squarely at the intersection of deep tech, frontier tech, and the kinds of critical industries — AI infrastructure, advanced manufacturing, energy, defense — where the next decade of value creation will happen. It's a category that didn't exist as a commercial market until very recently.

The first paying customer is the hinge moment. Until you have one, it's a thesis. After you have one, it's a market.

I Wrote the First Check

I led TBC's pre-seed round and wrote the very first institutional check into the company. That's not a marketing line — it's literally true. There was no other institutional investor on the cap table when I signed.

This is the part of the job I actually live for. The pre-seed call is the one where the founder is describing something that, if true, is enormous, and where the diligence is mostly about whether the people in the room are the right ones to bend reality toward the vision. There's no traction to point to. There's no comparable company to benchmark against. There's just the founders, the substrate of the idea, and a decision.

I said yes early. I'm glad I did.

What's Happened Since

Watching TBC operate has been, honestly, one of the more remarkable things I've seen in a decade of investing across hard tech.

The team has hit nearly every milestone they laid out in the pre-seed deck — and in several cases, they've hit them ahead of schedule. They've recruited an absurdly strong technical bench. They've moved from research demonstration, to a working product, to revenue from a paying customer for biological compute, to a $25M Seed led by one of the most thoughtful infrastructure investors in the country.

That sequence — from pre-seed thesis to commercialized first product — is one almost no deep tech company executes cleanly. It usually takes longer. It usually breaks somewhere in the middle. TBC just kept moving.

Why This Was a Refactor Investment

People sometimes ask me what makes something a Refactor deal. TBC is a useful case study.

We invest at the intersection of computation and the physical sciences. We back hard tech and deep tech across critical industries — aerospace, critical materials, energy, nuclear, defense, advanced manufacturing, and the bio-compute layer that increasingly sits underneath all of them. We lead or co-lead seed and pre-seed rounds with $1–2M checks for 5–10% ownership. We do this roughly 20 times per fund.

The structural choice that lets us be useful in moments like the TBC pre-seed is that I'm the only employee at Refactor. There's no associate triaging the meeting. There's no investment committee debating whether the thesis fits a slide template. When a founder building something genuinely new shows up, the person hearing the pitch is the same person writing the check, and the decision can happen in the same week.

For TBC, that mattered. Alex and Jon needed a partner who could move at the speed of the conviction, not at the speed of a process.

What I'm Watching Next

The first paying customer is the beginning, not the end. The interesting question isn't whether TBC has a customer — they now do. The interesting question is how fast the second, fifth, and twentieth come.

If biological compute behaves the way most platform technologies behave, the curve is non-linear. The first customer is the hardest. The next handful come from the gravity created by the first. Then, at some point, the category stops being a curiosity and starts being infrastructure.

I think TBC is closer to that point than the outside world realizes.

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