Vandalia Research has developed a PCR system that scales DNA sequence production from the bench to commercialization. Triathlon™, a continuous, large-scale PCR system, is the heart of this system. As Derek Gregg, vp of business development, explained, “DNA vaccines have a lot of potential advantages, especially in manufacturing, but they are mainly based on plasmid DNA, which is propagated in bacteria. Therefore, removing the bacteria remnants is important.” And, he added, “Often, only one-third of the plasmid is used because much of the sequence is required for replication in bacteria and isn’t used by the vaccine.”
Using PCR to amplify the DNA, however, could eliminate many of the challenges associated with plasmid purification. As yet, PCR hasn’t become popular for this use because of the many heating and cooling steps, the large quantities of plasmids needed, and the time required for processing.
Triathlon resolves those issues through a continuous process that currently produces about 50 mg of DNA per day. The PCR reagents are transported through tubing that wraps around a cylinder, which rapidly heats and cools the solution, saving 40 to 90 seconds per cycle. The flow is continuous, eliminating the need to pool products from plates. The process results in reduced labor, decreased turnaround time, and reduced risk of contamination. The Triathlon is scalable, and the next-generation machine is expected to be able to produce up to 1 g or more of DNA per machine, per day, Gregg noted.
PCR also produces linear DNA, so researchers can work with only the fragments of interest. “Some studies have shown that it’s easier to get smaller DNA fragments into the cell, which allows researchers to get better expression,” Gregg said. “The resulting vaccine also may be more transient,” he continued, allowing the DNA fragment to do its job and leave.
Speed is a major benefit of this approach to plasmid production. Scaling up for manufacturing can be accomplished in a few days, versus the weeks or months needed for fermentation processes, Gregg said. “Therefore,” he pointed out, “this method could be particularly valuable in a pandemic. Vandalia offers large-scale PCR as a service.”