Gel beads composed of collagen reconstituted in alginate

Spherical gel beads of collagen/alginate were prepared by discharging droplets of a mixture containing collagen (1.07-1.9 mg/ml) and alginate (1.2-1.5% w/v) into 1.5% w/v CaCl₂ solution at 4°C. Collagen In the gel beads was reconstituted by raising the temperature to 37°C after alginate was liquefied by citrate. Scanning electron microscopy of the beads revealed the characteristic fibrous structure of collagen. To demonstrate the application of this new technique in cell culture, GH₃ rat pituitary tumor cells were entrapped and grown in the get beads. The immobilized cells proliferated to a density of 1.95 x 10⁶ cell/ml which is about an order of magnitude higher than that grown in the alginate beads.