In the development of a new biological product, it is important to remember that a successful R&D development project needs to be converted from a bench-scale concept to a bioproduction platform. This process development stage requires identifying ways to increase cell numbers to meet annual dosage demands, as well as to minimize direct contact with the cell product by developing a closed system for all culture manipulations. identifying a bench-scale platform that can scale to CGMP production scale eases the scaling process.
The Corning Life Sciences gas-permeable family of products — the HYPERFlask® cell culture vessel and the newly developed HYPERStack vessels — simplify the transition from bench to production floor. The HYPERStack vessels have been designed for closed-system use to meet the needs of large-scale adherent cell culture.
The gas-permeable technology and product design differs from traditional cell culture products as the cells attach to an ultrathin, gas-permeable polystyrene film instead of a relatively gas-impermeable, injection-molded polystyrene surface. The gas-permeable film allows for the elimination of the air gap within the flask, resulting in an overall reduced vessel height. For optimal cell attachment and growth, the gas-permeable film is Corning CellBIND® surface treated to create a hydrophilic, oxygen-rich surface.
The gas-permeable film is used to build growth chambers, where the gas exchange between the cells and the atmosphere occurs in the air spaces located beneath the cell layer. This differs from the traditional culture methods wherein the gas exchange occurs between the media surface and a large air gap above the cultures, such as in a traditional T-flask. This novel technology facilitates a more even gas exchange by the cells throughout the vessel.
This design allows for the stacking and manifolding of multiple growth chambers in a compact design. For comparison purposes, a HYPERStack-36 vessel that provides 18,000 cm2 of growth surface area requires a similar amount of incubator space as the Corning CellSTACK® 10-layer Culture Chamber, which consists of 6,360 cm2 cell growth surface area. This results in the HYPERStack vessels having high efficiency with regard to cell growth surface area per unit volume. Additionally, because the dimensions of the HYPERStack vessels maintain the perimeter footprint of the traditional Corning CellSTACK culture chambers, these vessels are compatible with existing automation equipment.
Another key feature incorporated into this unique vessel design that makes scaling to production-level needs easier is the use of BSE/TSE-compliant C-Flex tubing for liquid manipulations. All liquid transfer is conducted through the liquid-handling tubing connected to one manifold, whereas air escape and entry occurs through the other manifold. Addition and removal of fluids in HYPERStack vessel closed systems may occur through tube welding of various auxiliary vessels (e.g., media bags) to the HYPERStack tubing set or through the use of aseptic connectors.
The HYPERStack cell culture vessel family has been developed as a modular system, with the HYPERStack-12 vessel as the single module. These modules can be stacked, allowing the process to be scaled as required for the manufacturing facility and the annual dosage requirements of the product. Currently the HYPERStack-12 and HYPERStack-36 vessels are available, and the HYPERStack-120 vessel will be available by the end of 2011.
The modularity and stacking ability of the HYPERStack vessel allows process development departments the option of increasing the lot size by either using multiple smaller HYPERStack vessels or a single larger HYPERStack vessel. Table 1 depicts a potential scaling strategy based on the amount of product requiredTable 1: Number of vessels required to attain desired volumetric footprint
The Corning® gas-permeable family of products — which began with the HYPERFlask vessel and has recently expanded with the addition of the HYPERStack cell culture vessel — are a novel solution to easing the scaling process from bench-top to CGMP production process.
Depending on the optimal lot size for customer production requirements, either the HYPERStack-12 with 6,000 cm2 of cell growth surface area or the HYPERStack-36 with 18,000 cm2 of surface area can be selected. For manufacturing scale production, the 60,000 cm2 HYPERStack-120 layer vessel may be the optimal choice.
Pilar Pardo, Renee Gallagher, Vitaly Klimovich, and Greg Martin are with Corning Incorporated — Life Sciences, 2 Alfred Road. Kennebunk, ME 04043; 1-207-985-3111, fax 1-207-985-5202.