Hybrid artificial cells: microencapsulation of living cells.

In 1965, the use of artificial cells for the microencapsulation of living cells was demonstrated. At that time, this technique was also proposed for use in immunoisolation of endocrine cells, islets, and hepatocytes as hybrid artificial organs. Progress in the biotechnology of cell culture in the last 10 years has allowed this approach to be extensively investigated by an increasing number of centers. The author's recent studies concentrated on microencapsulation of hepatocytes as a model system. Such cells were implanted to increase the survival of galactosamine induced fulminant hepatic failure rats, or to decrease the high bilirubin levels in Gunn rats and xenografts of microencapsulated rat hepatocytes into mice provided immunoisolation. Furthermore, hepatocyte secreted hepatic stimulating factors (mw 110,000 D) accumulating in the microcapsules helps to increase the viability of the hepatocytes. In addition to these studies, a novel, two step cell encapsulation method was developed to improve immunoisolation and biocompatibility. Microencapsulation of microorganisms was also carried out using a model microorganism to convert serum cholesterol to carbon dioxide.