Cryopreservation of fibroblasts immobilized within a porous scaffold: effects of preculture and collagen coating of scaffold on performance of three-dimensional cryopreservation.

As a preliminary investigation to establish a cryopreservation method suited for bioartificial livers (BALs), three-dimensional (3-D) cryopreservation experiments with fibroblasts were performed, in which the cells were firstly seeded into a porous scaffold, and the scaffold containing the cells was then cryopreserved. After thawing, 65% of the initially applied cells were still attached to the scaffold, and this efficiency was significantly higher than that in the control experiments (39%), in which fibroblasts cryopreserved in a suspension were seeded into the scaffold. This higher efficiency was mainly caused by higher immobilization efficiency at the time of cell seeding (83%) than in the controls (54%). Collagen coating of the scaffold in the 3-D cryopreservation enhanced immobilization efficiency at the time of cell seeding, and 1-day precultures before the 3-D cryopreservation considerably improved cell growth after thawing. From these favorable results, this 3-D cryopreservation method may become useful for developing BALs.