Trapped water of human erythrocytes and its application in cryopreservation

The novel differential scanning calorimetry method as a technique for determining human red cell volume during freezing process has been reexamined and has been shown to provide a final erythrocyte volume to be 53% of its isotonic value after freezing from 0 to −40 °C. A new type of electronic particle counter (Multisizer™ 3, Beckman Coulter Inc., USA) was used to measure cell volume changes in response to equilibration in anisotonic media, and which gave out an equilibrated volume to be 57% of cell isotonic value in solution of 3186 mOsm. Both of these results indicate that 34–40% of intracellular water is trapped and is unavailable for participation in osmotic shifts. These findings are consistent with the published data that at least 20–32% (v/v) of the isotonic cell water is retained within RBCs. Then the application of trapped water in both simulation of freezing models and freezing-drying control was pointed out.