Investigation of the Influence of Cell Density of Human Fibroblasts Cryopreserved Inside Collagen Sponges at Various Cooling Rates
Abstract:The influence of cell density of cells cryopreserved inside a collagen matrix at various cooling rates was investigated. Human fibroblasts were three-dimensionally cultured for 2 days in a collagen sponge (20 mm in diameter and 1 mm in thickness) as an extracellular matrix to imitate biological tissue (artificial tissue). Different cell densities for the artificial tissue were used, from 105 to 107 cells/cm3. Four artificial tissues were first stacked in a test chamber, frozen at a cooling rate of 0.3 to 50°C/min in a solution of Dulbecco's Modified Eagle Medium, 20% Fetal Bovine Serum and 10% dimethylsulfoxide, kept frozen below – 185°C for 2 hours, and then finally thawed. Membrane integrity of fibroblasts using a trypan blue exclusion assay was evaluated as an index for post-thaw cellular viability. Results show that with increasing cell density, the post-thaw membrane integrity decreased. Therefore, in the cryopreservation of biological tissue, it seems high cell density is one factor which causes a decline in viability.
Document Type: Research Article
Publication date: September 1, 2007
CryoLetters is a bimonthly international journal for low temperature sciences, including cryobiology, cryopreservation or vitrification of cells and tissues, chemical and physical aspects of freezing and drying, and studies involving ecology of cold environments, and cold adaptation
The journal publishes original research reports, authoritative reviews, technical developments and commissioned book reviews of studies of the effects produced by low temperatures on a wide variety of scientific and technical processes, or those involving low temperature techniques in the investigation of physical, chemical, biological and ecological problems.