Abstract: Culture systems for human pluripotent stem cell (PSC) expansion are essential for generating an almost unlimited pool of cells capable of differentiating into all three germ lineages, for cell-based therapies. To transition PSC therapy research from the laboratory to clinical applications, there is a critical need for high-quality materials that comply with GMP standards, undergo rigorous quality and safety testing, ensure raw material traceability, and are supported by comprehensive regulatory documentation. To address these stringent requirements, we have developed Gibco™ Cell Therapy Systems (CTS™) StemFlex™ Medium. CTS™ StemFlex™ Medium is xeno-free and supports the expansion of high-quality PSCs and is designed to support challenging applications within the PSC workflow. Our data demonstrate that PSCs cultured long-term in CTS™ StemFlex™ Medium maintain essential PSC characteristics, including greater than >95% expression of OCT4/NANOG pluripotency markers, normal morphology, trilineage differentiation potential, and normal karyotype. This medium offers a flexible feed schedule including a weekend-free option, and compatibility with multiple defined matrices and passaging reagents. CTS™ StemFlex™ Medium excels in supporting stressful PSC applications, including single-cell passaging, with a consistent cumulative fold expansion over 10 passages. Furthermore, CTS™ StemFlex™ Medium supports PSC recovery and expansion following electroporation-based delivery of the CRISPR Cas9-gRNA complex and facilitates the downstream clonal expansion of edited PSCs. Additionally, adherent PSCs cultured in CTS™ StemFlex™ Medium can be seamlessly transitioned to 3D culture using CTS StemScale™ PSC Suspension Medium, resulting in the formation of high-quality PSC spheroids with a linear fold expansion over multiple passages. In conclusion, CTS™ StemFlex™ Medium delivers robust performance in cell therapy workflows, providing a comprehensive solution to advance PSC research and therapy.
