Mosaic Biosciences Launches Tessaic™ Nano, an In Vitro VHH Library for Rapid Nanobody Discovery

Published: September 8, 2026 | Category: News, Press Release

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Mosaic Biosciences today announced the launch of Tessaic™ Nano, a fully human synthetic in vitro VHH library designed to accelerate nanobody discovery across therapeutic, diagnostic, and research applications. Tessaic Nano is the first library released under Mosaic’s Tessaic antibody library system, with Tessaic Fab, a curated set of Fab-format libraries, near launch.

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A Fully Human In Vitro Route to Single-Domain Candidates

Tessaic Nano gives clients a fast, fully in-house route to VHH candidates without the humanization step required for camelid-derived antibodies and without a camelid immunization program. Because the library is fully human and synthetic, candidates emerge ready for clinical development timelines from the outset.

The library incorporates donor-derived CDRH3 diversity alongside curated diversity across CDRH1 and CDRH2, informed by internal repertoire analysis of which diversity placements have produced the strongest hit rates. Diversity is sourced from immune material captured and processed entirely in-house. Germline selection is backed by literature-supported developability and pairing data, with liability filtering built into the design from the start rather than addressed downstream.

“Clients are increasingly running in vitro and in vivo VHH discovery in parallel to de-risk timelines and compare candidate profiles. Tessaic Nano gives us a rapid, fully human option built entirely in-house, and it complements the work we do with Abkyu on the in vivo side. Together, these options let clients choose the discovery route that fits their program, or run both.”

— Tracey Mullen, Chief Strategy Officer, Mosaic Biosciences

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In Vitro and In Vivo VHH Discovery Under One Program

The launch of Tessaic Nano follows Mosaic’s preferred partnership with Abkyu, a Boston-based in vivo VHH discovery specialist. Together, the two capabilities give Mosaic clients access to both in vitro and in vivo single-domain discovery routes under a single coordinated program.

For clients pursuing nanobodies, bispecifics, ADCs, or other VHH-based modalities, this means the ability to run parallel discovery strategies, compare candidate profiles, and choose the route, or combination of routes, that best fits the biology and the program timeline.

Tessaic Nano is available now. Mosaic will introduce the library at upcoming industry events, including Festival of Biologics Basel (October 13–15) and PEGS Europe (November 16–19).

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Connect with our discovery experts to discuss your program and explore how Mosaic can help move your ideas forward. Click to view the full press release here.

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