Towards the development of a bioartificial pancreas: effects of poly-L-lysine on alginate beads with BTC3 cells

A bioartificial tissue construct that consists of insulin-secreting cells entrapped in an alginate/poly-L-lysine (PLL) matrix offers a promising approach for the treatment of type I diabetes. Use of transformed cells has been proposed as a solution to the cell availability problem posed by islets. The growth characteristics of transformed cells in their sequestered environment and the effects of PLL on their metabolic and secretory activities have not yet been characterized. Our data demonstrate that mouse insulinoma beta TC3 cells proliferate while they are entrapped in both PLL-free and PLL-coated alginate beads. During this process, cell aggregates develop in the bead periphery, which increase in number and size with time. PLL is crucial for the long-term in vitro structural stability of beads, and it does not appear to affect the metabolic and secretory activities of entrapped beta TC3 cells. The implications of these findings in the development of a bioartificial pancreatic construct based on transformed cells are discussed.