Large sets of computer-designed antibody sequences need experimental testing before researchers can choose candidates for further development. Twist Bioscience, the biotech with operations in South San Francisco and Wilsonville, Oregon, is aiming to capitalize on that need with Express Screening Antibodies, a cell-free antibody production and binding characterization service it launched October 28, according to the launch announcement.
CEO and co-founder Emily M. Leproust, Ph.D., said that as AI-guided discovery expands the range of antibody candidates researchers can explore. The new service brings “speed and scalability to early-stage characterization,” she said in a press release. As a result, researchers can move broader candidate sets from sequence to data, iterate faster and focus downstream development resources on the most promising antibodies, according to Leproust.
The service extends the approach R&D World examined during its July factory-tour feature. Touring Twist’s South San Francisco headquarters, Leproust said AI has changed the size of antibody orders. Drug developers “used to look at 100 antibodies at a time,” she said. Now AI models running on pharma supercomputers propose thousands, and “they’re gonna need to get from us those thousands so that we can try which one is the right one.” For about 100 antibodies, she said, customers can choose among several vendors. At 1,000 or 10,000, she argued, few can synthesize, produce and test that many, and Twist runs each of those steps in-house: “forget it. We’re the only game.” Express Screening Antibodies is meant to be the cheap, fast first pass on those large batches. Twist’s product sheet pitches it for triaging AI-designed candidates “before a small lead set advances to mammalian re-expression.” When R&D World compared drug discovery to a chess game in which Twist supplies the board, Leproust said Twist is giving customers “more pieces”: “it’s all about shots on goal.” For Twist, those pieces are biologics, the antibody and other protein candidates built from the DNA it synthesizes, and the cell-free service aims to make each of those shots cheaper to try.
The service runs on ALiCE (Almost Living Cell-free Expression), a protein-production system from LenioBio, a Düsseldorf, Germany, company that makes proteins for customers and supplies the system for use in their own labs. ALiCE makes proteins in a lysate, an extract of broken-open tobacco BY-2 plant cells, according to a 2025 study with LenioBio co-authors. Customers submit variable-region sequences, the parts of an antibody that recognize its target. Twist synthesizes the heavy- and light-chain genes as linear DNA on its silicon platform, which skips a cloning step, expresses them in 50- or 100-microliter cell-free reactions on 96-well plates and purifies the assembled antibodies from the lysate in a single Protein A capture step, according to the product sheet. The output is full-length human immunoglobulin G1 (IgG1) or one of two smaller fusion formats. Those are scFv-Fc, a single-chain variable fragment joined to an antibody’s Fc (fragment crystallizable) tail, and VHH-Fc, a single-domain binder derived from camelid heavy-chain antibodies joined to the same tail. The launch announcement lists quantities of 5 to 20 micrograms. The product sheet gives average yields by format and reaction size: about 10 to 15 micrograms of IgG from a 50-microliter reaction and 15 to 20 micrograms from 100 microliters, and about 10 to 30 micrograms of the fusion formats. An SPR run uses 5 to 15 micrograms per construct, and Twist reports yield for each sequence as an early screening signal. Researchers can route them directly into surface plasmon resonance (SPR) binding characterization, which measures how fast and how tightly each candidate binds its target.
Cell-free antibodies ship five business days after Twist receives the order, and orders that add SPR binding data take eight to ten business days, according to Twist’s product specifications. Production in mammalian cells takes longer before any assay starts: 8 to 11 business days in HEK293 cells, a human cell line derived from embryonic kidney tissue in the 1970s and widely used to make research proteins, and 11 to 14 in CHO (Chinese hamster ovary) cells, the line drugmakers most often use to manufacture antibody drugs. Twist says each figure reflects its fastest configuration, and format, order size and sequence complexity can lengthen it. The faster route yields less material at lower purity: about 70% for cell-free antibodies, compared with about 95% for most HEK293 and CHO formats, according to the specifications. Twist lists published pricing for the cell-free service starting at $87.75 per variant.
The launch announcement describes assessment of thousands of antibodies per day for AI and machine learning (ML) discovery workflows, and the product sheet puts the scale at hundreds to thousands of candidates triaged per campaign. For validation, Twist ran a head-to-head SPR comparison of eight antibodies against seven antigens, measuring each as cell-free IgG and as a reference antibody made in HEK293 cells. The two sets of equilibrium dissociation constants (KD), a measure of binding strength in which lower values mean tighter binding, correlated at a Pearson r of 0.973 on a log-log scale, and seven of the eight cell-free values fell within threefold of the HEK293 values. The tightest binder measured 12.6 picomolar.
Researchers can advance selected antibodies into HEK293 or CHO expression, where a 1-milliliter HEK293 run yields an average of 180 micrograms, for further characterization. That includes developability assays for thermal stability, aggregation, self-interaction and nonspecific binding, which test whether a binder is likely to hold up as a drug candidate. Twist offers those assays only for its two mammalian systems, and SPR affinity measurement is the only one of its six binding assays that lists cell-free material. The cell-free step works as a binding screen ahead of that more extensive testing.
The launch adds to the routes AI design platforms already use to send candidates to Twist. Amazon Bio Discovery, which AWS introduced in April, lists Twist, Ginkgo Bioworks and A-Alpha Bio as the lab partners that synthesize and test its designs. In May, Benchling added in-notebook ordering of gene synthesis, antibody expression, binding and developability assays from Twist, Adaptyv and Ginkgo. On September 16, Twist joined Lilly TuneLab, Eli Lilly’s AI drug discovery platform, as a provider of antibody characterization data, including for AbLab, a model that predicts antibody developability.