Zhileng xuebao (Jan 2025)
Research on the Crystallization Properties of Oocytes Encapsulated in Sodium Alginate Hydrogel
Abstract
Microencapsulation technology based on sodium alginate hydrogels can be used to optimize freezing and rewarming procedures and to reduce cryo-damage to cells and tissues. In this paper, the morphology of oocytes in different concentrations (0.5%, 1%, 1.5%, and 2%) of sodium alginate hydrogels was first observed to determine the safe concentration for their encapsulation. Secondly, the crystallization temperature and crystallization behavior of sodium alginate hydrogels with different concentrations (0.5%, 1%, 1.5%, 2%) were systematically investigated using cryo-microscopy, and the morphology and crystallization of oocytes were compared when they were cooled down/retempered in the base solution, cryoprotectant solution. Finally, the freezing effect of sodium alginate antifreeze hydrogel encapsulated oocytes prepared by solvent replacement type and physical mixing type were compared. The results showed that oocytes maintained their overall morphology and volume better in sodium alginate gels at 0.5% and 1% concentrations. Furthermore, oocytes in both the 1% sodium alginate group and the cryoprotectant solution group of 12.5% DMSO + 12.5% EG + 0.5 M trehalose did not produce intracellular ice during the cooling process；Additionally, compared with the physical mixture, oocytes in the solvent replacement group of hydrogels did not produce intracellular ice during the cooling process, and the cells retained their normal morphology after rewarming.
