Exploring the Potential of Hydrogels for Alternative Cell Storage

Efficient long-term storage of mammalian cells is crucial for their applications in cell therapy and biologics production, but cryopreservation with additives such as DMSO and FBS can make it expensive, ethically challenging as well as raise potential complications further downstream. Desiccation, which involves removing all water from the cells, is a potential alternative to cryopreservation, but most cells require water for survival, and a supplement media/substrate may be necessary. Therefore, the presented study aimed to explore the feasibility of a number of hydrogels as protectants for mammalian cells during low-water, long-term storage, with a particular focus on gelatin, GelMA, agar, and a nanofibrillar cellulose-based commercial hydrogel. Material characterisations with dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and swelling degree ratio analyses were performed on these materials. C6 glial cells and L929 fibroblasts were desiccated for 6, 24, 48, and 72 h and assessed for their metabolic activity changes upon rehydration. The results demonstrated that desiccation temperature has a greater influence on cellular activity-based survival compared to the type of hydrogel that they are incorporated within. This study shows that entrapping cells in a suitable substrate can extend survival of cells in low-water conditions; gelatin- and nanofibrillar cellulose-based hydrogel materials could be promising candidates for long-term storage and delivery of mammalian cells for therapeutic applications.