Differential cryopreservation outcomes of cardiosphere-derived cells in alginate scaffolds and alginate-poly-L-lysine microcapsules.

The clinical translation of three-dimensional (3D) cardiac cell-based constructs is limited by the lack of effective preservation strategies capable of maintaining cell viability and function. Biomaterial-based platforms, such as bioprinted scaffolds and microencapsulation systems, have been developed to enhance the therapeutic potential of cardiosphere-derived cells (CDCs), although their post-cryopreservation performance remains poorly understood. Here, we compared cryopreservation outcomes between 3D bioprinted alginate-based composite scaffolds (alginate-nanocellulose-hyaluronic acid) and alginate-poly-L-lysine-alginate (APA) microcapsules. Under physiological conditions, CDC-seeded scaffolds supported cell viability, metabolic activity, and sustained paracrine factor secretion. However, after cryopreservation, scaffold-based constructs showed poor cell survival and minimal metabolic recovery. In contrast, microencapsulated CDCs maintained viability and progressively recovered metabolic activity under both dimethyl sulfoxide (DMSO) and DMSO-free conditions. Importantly, microencapsulated CDCs preserved growth factor secretion and differentiation capacity after thawing. These findings support the potential of microencapsulation as a promising approach for the development of cryopreservable CDC-based therapies for cardiac regeneration.