Production and preservation of serum-free human umbilical cord-derived mesenchymal stem cell sheets

Abstract: Background Human umbilical cord-derived mesenchymal stem cells (UC-MSCs) have attracted much attention because of their fast self-renewal, multipotent nature, painless collection, and compliance for standard amplification. Several types of culture media and systems have been used for large-scale expansion of UC-MSCs and preparation of UC-MSC sheets; however, most rely heavily on fetal bovine serum (FBS) and exogenous growth factors for optimal cell proliferation. Residual bovine serum albumin (BSA), a macromolecular protein in FBS, and exogenous growth factors in final products pose the potential threat of allergic reactions or tumorigenic risks in humans. Methods In this study, the production process of UC-MSC sheets was standardized, including donor screening, cell bank establishment and quality control, and cell sheet production and quality control. Serum-free culture medium and pharmaceutical grade coating matrix were used to form UC-MSC sheets to reduce the risk of BSA and exogenous growth factors in clinical application. Additionally, the preservation solution for and method of the UC-MSC sheet were developed for preservation and transportation before cell sheet transplantation. Then, quality standards of the UC-MSC sheet involving product characteristics, safety and functionality were formulated according to national and international regulations. Finally, the UC-MSC banks and the UC-MSC sheet products were identified according to the established quality standards. Results This technology enables UC-MSC sheets to be produced safely and stably while preserving the cell viability of UC-MSC sheets above 70% in 24 hours. The quality standards for the UC-MSC sheets were established in this study. Both the fresh and 24-hour preserved UC-MSC sheets met the established quality standards. Conclusion The preparation and preservation of clinical grade serum-free UC-MSC sheets provides the possibility for the clinical application of cell therapy.