Abstract
For the final purpose of developing a module by immobilizing floating spheroids once formed on flat plates to inner surfaces of support materials, first, we have investigated culture conditions for selective formation of floating spheroids on surfaces coated with polylysine (PL), and effect of surface characteristics on stable re-attachment and expression of functions. Culture conditions which improve the initial spreading of the cells increased spheroid diameter, and had a retarding effect on the formation of foating spheroids, probably because these conditions aggregated more cells into one spheroid. The most rapid formation and floating of spheroids were observed in a medium supplemented with insulin and dexamethasone. The spheroids formed in this hormone condition on PL-coated square dishes (Nunc; 500 cm2) were collected by gentle pipetting on the 7th day, and were reseeded onto surfaces coated with various concentrations of PL and fibronectin (FN) solution.“Stably-attached”aggregates were obtained on surfaces coated with both PL and less than 5μg-FN/mL, and the ones coated with PL alone. These“stably-attached”spheroids secreted albumin for 2 weeks at a high level.
