Traditional custom DNA production often involves assembling a sequence, introducing it into bacteria, growing the cells, and extracting the resulting material. Ribbon Bio is promoting a cell-free alternative that avoids bacterial propagation, which can be difficult when sequences are toxic or unstable in bacteria and adds steps to the workflow.
The company’s method uses software to identify sequence features such as GC content, repeats, homopolymers, and secondary structures. It then designs oligo pools and uses proprietary enzymes to assemble DNA fragments into the finished molecule. Ribbon says removing the bacterial host also avoids endotoxin and residual bacterial genomic DNA in the product.
Ribbon initially offered the technology through its MiroSynth synthesis service, which it says remains available for highly complex molecules. Its MiroMine kit brings the process into customer laboratories. The early-access version is designed to build molecules up to approximately 7 kilobases using Standard lab equipment, either manually or with automation; platform scripts are in development.
In data from its own runs, Ribbon reported 100% sequence-perfect reads for molecules near 3.4 and 6.8 kilobases, and 88% for a construct of about 4 kilobases. The company noted that the latter result was below its stated 90% accuracy floor. It also reported assembling fragments with a range of global and local GC content, as well as repeats and homopolymers, within a four-hour workflow. Endotoxin levels were at or below 0.1 units per microgram, and bacterial genomic DNA was not detected.
Flock Bio, which builds pooled custom DNA libraries, is an early user. In an internal test, its team assembled all 12 fragments it ran through MiroMine; about half were described as high-complexity. Flock said fragment assembly, cleanup, checks, and pooled ligation could be completed in one working day with the kit. The company contrasted this with cloning, which it said adds three to four days, and said a full library could be delivered within a week after receiving an oligo pool.
The companies presented the approach as a way to shorten DNA-production timelines and work with sequences that may not be maintained successfully in bacteria. The reported results are based on Ribbon Bio’s runs and Flock Bio’s internal study, and the MiroMine program remains in early access.