Anthropic says Claude designed binders against scorpion neurotoxins

On 20 October 2026 Anthropic reported that an internal research model, running inside Claude Science, designed protein binders against scorpion neurotoxins. A binder is a small protein meant to attach tightly to a target. The five toxins were Cn2, Ts1, AaH I, AaH II and LqhIII. The designs were aimed at the part of each toxin that latches onto sodium channels in nerve cells. Anthropic cites 1.2 million stings or more a year, and more than 3,250 deaths, mostly among children.

Claude picked the toxin structures and the amino-acid positions to grip, and used 12 design tools. It worked mostly on its own for 64 hours, with four follow-up prompts from the team. Adaptyv Bio and Twist Bioscience then made the designs and measured binding. A design counted only if it bound in every replicate, every measurement was 1 µM or tighter, and it did not stick to an unrelated human protein. LqhIII was tested only at Adaptyv Bio.

Seventeen designs met that bar, each against a single toxin. None of the designs aimed at more than one toxin met it for more than one. Anthropic has not tested whether any binder stops the toxin in cells or in animals, so it does not claim an antivenom. Its two strongest Cn2 binders, Cn2-B1 and Cn2-B2, bound in the single-digit nanomolar range and competed with an antibody, LR, that has been reported to protect mice from Cn2. Anthropic is releasing all 211 tested designs and their binding data.