RESUMO
In order to investigate the effect of cell immobilization in calcium alginate gels on cell physiology, we immobilized Vero or N2a neuroblastoma cells in gels shaped either as spherical beads or as thin membrane layers. Throughout a culture period of 4 weeks cell viability, RNA and cytoplasmic calcium concentration and glutathione accumulation were assayed by fluorescence microscopy after provision of an appropriate dye. Non-elaborate culture conditions were applied throughout the experimental period in order to evaluate cell viability under less than optimal storage conditions. Vero cell proliferation was observed only in spherical beads, while N2a cell proliferation was observed in both configurations until the third week of culture. Increased [Ca2+]cyt could be associated with cell proliferation only when cells were immobilized in spherical beads, while a considerable decrease in the biosynthesis of reduced glutathione and RNA was observed in cells immobilized in thin membrane layers. The observed effects of the shape of the immobilization matrix may be due to differences in external mass transfer resistance. Therefore, depending on cell type, cell proliferation could have been promoted by either increased (Vero) or decreased (N2a) nutrient and oxygen flow to immobilized cells. The results of the present study could contribute to an improvement of immobilized cell sensor storability.
