Google DeepMind introduced SynthID Bio, a way to put hidden watermarks into AI-designed proteins that stay in the physical protein.

What DeepMind built

Google DeepMind introduced SynthID Bio on 30 Sep 2026 as a proof of concept, TechRepublic reported. It extends SynthID, Google's watermark for AI-made digital content, to proteins designed with AI.

When a design tool picks amino acids, SynthID Bio nudges the choice slightly to leave a hidden pattern in the sequence. A matching checker can later tell whether a sequence came from a SynthID Bio design process. DeepMind used it with AlphaProteo and a modified ProteinMPNN to design protein binders. A separate version, built into part of AlphaFold 3, marks predicted 3D structures.

What the lab tests showed

DeepMind tested watermarked binders against three targets: VEGF-A, the receptor-binding part of the SARS-CoV-2 spike protein, and PD-L1. They matched unmarked designs on hit rate, binding strength and sequence variety. TechRepublic gave no figures.

DeepMind also added the method to the Evo 2 model to watermark an AI-designed bacteriophage, which still worked in early lab tests. More detail on that work is due in a separate paper. The experiments cover a limited range of designs.

Why it matters and its limits

DNA synthesis firms screen orders against lists of known threats, but AI-made proteins may not look like known ones. A watermark could give them another signal about where a sequence came from. It could also help keep databases such as UniProt and GenBank free of mislabelled synthetic entries.

DeepMind admits that stopping people from removing the watermark on purpose is a major challenge. Short proteins may be too small to carry a reliable mark, and researchers question how well it works for enzymes. Wider use would need shared standards among designers, synthesis firms and databases.

What happens next

The research is published in Nature. DeepMind is releasing the paper, code, lab data and model weights to the research community and invites outside testing.