ABSTRACT
BACKGROUND: Viscosity is an important property of cryoprotectant solutions because it directly influences diffusion and reaction at liquid state. OBJECTIVE: To measure the viscosities of concentrated NaCl-H(2)O and Me(2)SO-NaCl-H(2)O solutions at subzero temperatures down to -50 degree C. MATERIALS AND METHODS: Solution viscosity was measured with a rotary viscometer coupled with a thermostat bath. Two viscosity models, Laliberté model and Williams-Landel-Ferry (WLF) model, were employed in the correlation and prediction. RESULTS AND CONCLUSION: The Laliberte model performed well to correlate the viscosities of NaCl- H(2)O solutions measured here and the viscosities of Me(2)SO-H(2)O solutions found in the literature. The parameters obtained were used to predict the viscosities of Me(2)SO-NaCl-H(2)O solutions. The average discrepancy between the calculation and the experimental data was 19.0%. With the WLF model, the average discrepancy between the calculation and the experimental data for ternary solution was 5.4%.
Subject(s)
Cold Temperature , Cryoprotective Agents/chemistry , Sodium Chloride/chemistry , Sulfuric Acid Esters/chemistry , Water/chemistry , Models, Chemical , Solutions , ViscosityABSTRACT
The successful cryopreservation of reproductive cells has important practical significance in many fields. In order to improve the recovery rate and viability of cryopreserved cells, it is necessary to study the permeability characteristics of cell membrane to both water and cryoprotectant. In this paper we review the studies on membrane permeability of animal reproductive cell for the recent years. We firstly list the typical permeability data of spermatozoa and oocyte membrane for water and cryoprotectant. We then analyze the effects of these characteristics on the design of cryopreservation protocol. We also introduce the latest experimental methods to measure the cell membrane permeability.
Subject(s)
Animals , Female , Humans , Male , Cell Membrane Permeability , Physiology , Cryopreservation , Methods , Oocytes , Cell Biology , Spermatozoa , Cell BiologyABSTRACT
Some tissues, such as cartilage and cornea, carry an internal fixed negative charge, leading to a swelling pressure that is balanced by tensile stress in the tissue matrix. During the addition and removal of cryoprotectants the changes in osmotic pressure will cause the tissue to deform. Because of the fixed charge and osmotic deformation, the permeation process in such tissues differs from ordinary diffusion processes. In this paper a biomechanical multi-solute theory is introduced to describe this process in cartilage tissue. Typical values for the physiological and biomechanical properties are used in the simulation. Several parameters - the aggregate modulus, the fixed charge density and the frictional parameter - are analyzed to show their impact on the process. It is shown that friction between water and cryoprotectant has the greatest influence but the fixed charge density is also important. The aggregate modulus and the frictional parameter between the cryoprotectant and the solid matrix have the least influence. Both the new biomechanical model and the conventional diffusion model were fitted to published experimental data concerning the time course of mean tissue cryoprotectant concentration when cartilage is immersed in solutions of dimethyl sulphoxide or propylene glycol: in all cases and with both models a good fit was obtained only when a substantial amount of non-solvent water was assumed.
Subject(s)
Cartilage, Articular/metabolism , Cryoprotective Agents/metabolism , Animals , Models, Biological , Permeability , SheepABSTRACT
Cryopreservation is essential for the long-term storage and banking of cartilage grafts. This paper reviews the developments on the cryopreservation of cartilage and transplantation of cryopreserved cartilage grafts during the past 10 years. It is stated that the current technologies for cryopreservation of cartilage grafts are not mature. Further systematic studies are necessary.
