Oxygen Transfer Method
Traditional bioreactors mix solutions of cells with rotating blades and push in air with bubbles (sparging), similar to a fish tank. But the shear force of the blades and even the bubbles, once they burst, damage delicate mammalian cells. An alternative technology now in use eliminates the blades by rocking plastic bags attached to a board, but this method is also mechanically inefficient.
Dr. Hui and his team devised a better method based on plastic bags that shake the cells in culture media. The swaying contents roll up the sides of the plastic bags, allowing cells to acquire oxygen in the process. The magic ingredient is a special type of plastic that is covered with microscopic dimples on the surface that attract oxygen from ambient air. The repetitive washings trap oxygen in the form of dissolved microscopic bubbles, which do not damage mammalian cells.
This dissolved oxygen transfer method is the underlying technology behind a line of patented bioreactors, including suspension and perfusion bioreactors. The bioreactor product line, named Current, ranges in size from 20 mL to 300 L. Current bioreactors offer a high-density cell culture system for protein and antibody production and vaccine manufacturing. The ready-to-use plastic bags come in sizes to fit different Current bioreactors.
AmProtein also sells single-use, plastic miniature shaking and rolling bioreactor systems that are ideal for studying early-stage process development. The mini-bioreactor vessels hold volumes of 20, 40, 150 mL, 1 L, and 2 L and up to 15 of the bottles fit into a mini-bioreactor. All of the company’s bioreactors can be used for growing high-density CHO cell suspension cultures, as well as vaccine manufacturing cell lines, such as Vero, MDCK, and EPC cells. “The platform is scalable from bench to manufacturing and makes existing industrial bioreactors obsolete,” says Dr. Hui.
AmProtein scientists are working to improve the bioreactors by developing biodegradable, or green, plastic containers. If successful, “this will be a first for the biotechnology industry,” says Aziz Joudi, executive business associate. The researchers are experimenting with bacterial fermentation by E. coli to generate the biodegradable plastic, which shows good oxygen transfer properties.