A new microencapsulation procedure involving an allaqueous phase system was developed. Viable cells or tissues were suspended in sodium alginate droplets, which then were gelled by calcium chloride solution. A permanent, semipermeable membrane was formed on the surface layer of the temporary gel capsules by treatment with a solution of polylysine. Finally, true living cell-containing microcapsules were produced by "liquefying" the gel within the microcapsules through calcium-ion removal by simple ion exchange. Microencapsulated living cells and tissues continued to grow and flourish. In tissue culture medium, microencapsulated rat pancreatic islets continued to release insulin and remained sensitive to glucose and theophylline stimulation, responding with a typical physiological biphasic insulin-release pattern for over 2 months. Microencapsulation of other viable cells and tissues such as red blood cells, hepatoma cells, sperm cells, and pancreatic endocrine tissues also was successful.
Keyphrases Semipermeability-membranes of microencapsulated viable hepatoma cells and microencapsulated viable pancreatic islets Pancreatic islets-viability within microcapsule demonstrated by insulin release pattern and histological staining Microencapsulation-symposium, preparation of viable microencapsulated hepatoma cells and pancreatic islets, semipermeable membranes Microencapsulation is a process in which small, discrete, solid materials, liquid droplets, or gases are completely enveloped by an intact membrane. The functions of the capsular membrane are to protect the material within and to control the flow of materials, inside and outside, across the membrane.