Collagen-coated Ba2+-alginate microcarriers for the culture of anchorage-dependent mammalian cells

Several types of microcarriers suitable for large-scale cultivation of mammalian cells are commercially available. However, many of these carriers have disadvantages, e.g., the need for enzymatic digestion for cell harvesting, size limitations and insufficient biocompatibility. These limitations have been overcome by the development of collagen-coated Ba2+-alginate microcarriers. Ba2+-alginate microspheres, made with the air-jet droplet generator technique, were collagen-coated by incubation in a 0.5% collagen solution, with subsequent gelling of the collagen layer around the alginate microspheres. Human chang liver (CCL-13) and mouse fibroblast (L929) cell lines were cultivated in stationary, unstirred cultures as model systems. After a lag phase of nearly 24 h, the cells grew rapidly on these microcarriers and reached confluence after 3 days. The microcarrier cultures were stable for an additional 4-9 days and longer: Cells were harvested either by trypsinization or by dissolution of the alginate matrix using 5 mM EDTA. The main advantages of this new microcarrier system are that the preparation procedure is easy and can be accomplished on demand with standard laboratory equipment.