Microcarriers Microporous

Microporous microcarriers Biosilon Polystyrene with negative surface charge Nunclon... 

Photograph taken under an optical microscope of Vero cells growing on microporous microcarriers. 

This method opened up both industrial production opportunities and allowed research laboratories to easily produce substantial quantities of developmental products. Microcarrier culture is the most versatile, reliable, and characterized procedure for unit volume scale-up of anchorage-dependent cells. It has had widespread use for industrial processes [vaccines, interferon, tPA, and human growth hormone (hGH)] as well as many developmental uses, has been scaled-up to 4000 L, and has the potential for process intensification by perfusion with spin filters or by the use of microporous microcarriers. 

Many microporous beads are available, as are systems such as the Pharmacia Cytopilot using Cytoline porous microcarriers. There is a preference for microporous microcarriers that could be used in stirred, rather than fluidized, bioreactors, and these are now available (Cellsnow and ImmobaSil). ImmobaSil is of particular value as it is extremely permeable to oxygen, is a non-animal product safe from bovine contaminants, is robust, and can be used in all culture modes. 

Cross-sectional area and is adjusted so that the magnitude of fluid mechanical forces (proportional to the aspect ratio) within the bed is below damaging levels (Fig. 13). Fluidized beds differ from packed beds in that the perfusing fluid motion maintains the microcarriers in suspension. Packed-bed systems have been shown to support cell densities exceeding 10 cells/mL when using microporous microcarriers (500 to 850 lvc in diameter). In addition, packed beads (1.5-mm diameter) have been used to entrap aggregates of hepatocytes. The latter application was shown to maintain a relatively stable level of albumin secretion (a liver-specific product) for up to 3 weeks. 

The potential applications of such a polymerization technique for preparing novel polymeric materials include microfiltration, separation membranes, polymer blends with a unique microstructural morphology, and porous microcarriers for cultures of living cells and enzymes [7]. Some other interesting ideas about the preparation of novel materials include the conductive composite film [95] and microporous silica gel [96]. 

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