Optimization study on the rehydration process of lyophilized human platelets

Long-term preservation of human platelets will greatly reduce the risk of their shortage. Lyophilization has been proved feasible for this purpose. For the recovery of lyophilized platelets, rehydration is an important process. In this paper, the rehydration processes for 1 mL and 2 mL samples were studied. The effects of prehydration duration (15, 30, 60, 90, 120 and 150 min) in 37°C water vapor and the concentration of rehydration solution (25%, 50%, 75%, 100% platelet-poor plasma) on the recovery rate, MPV (mean platelet volume) and PDW (platelet distribution width) were investigated. The mass changes during the prehydration process were weighed. The optimized rehydration conditions are as follows: (1) for 1 mL sample, the prehydration duration was 15 min and for 2 mL sample the prehydration duration was 90 min; (2) the rehydration solution was 75% platelet-poor plasma. Under optimized conditions, the morphology of the rehydrated platelets kept normal and their ultrastructures kept intact, their aggregation capacity to thrombin (1 U/mL) was 82.8% of the fresh ones. These results will be helpful for designing the freeze-drying protocols for human platelets.