Mimicking Large-Scale Reactors
One of the knocks on early-stage use of disposables is significant difference in form factor between low-volume, development-stage cell culture performed in plastic, and full-scale processing in stainless steel. Richard Mirro, a product manager at New Brunswick Scientific (NBS) provided some insights into this discrepancy and how to overcome it.
He described new products from NBS that include 5 L and 14 L stirred-tank single-use vessels that replicate traditional autoclavable bench-scale reactors “while providing all the benefits of disposable technology.” A key component of the new reactors is their stirred-tank design, which mimics agitation mechanisms in larger stainless steel bioreactors.
“The downside of competing products is the difficulty in transferring from a rocker-based system to a 5,000 liter fixed-tank system,” Mirro said. “Unless you’re transferring to a similar system, there are scalability issues.”
The new bioreactors are constructed from translucent, USP Class 6 polycarbonate or polystyrene, making the reactors light and easy to move around, Mirro noted. They are fitted with noninvasive pH and dissolved oxygen sensors. As fully disposable systems, they require no cleaning or autoclaving or unthreading of ports or head plates. “You wouldn’t ever think they were made of plastic,” he said.
What if someone is tempted to re-use them? “The reactors are designed specifically to prevent re-use,” Mirro assured. “You can’t clean or disassemble them without damaging them. They’re basically uncleanable, and because they’re made from plastics they can’t be autoclaved without deforming.”
The single-use bioreactors are a bit more expensive than plastic film bio-bags, but their advantages more than make up for the extra cost, according to Mirro. “Compared with a traditional reactor, dollar for dollar, you’re either breaking even or saving significant money if you calculate in autoclaving, cleaning solutions, and validation, plus the additional effort saved in tech transfer and upscaling.”