Abstract
Basic fibroblast growth factor (bFGF) and Transforming growth factor-beta (TGF-β) are key regulators of human pluripotent stem cell (hPSC) maintenance, supporting pluripotency and self-renewal. bFGF is particularly critical for sustaining the undifferentiated state and is commonly supplied through feeder-derived conditioned media. Similarly, TGF-β promotes hPSC expansion by modulating signaling pathways and contributing to a supportive stem cell niche. In this study, we investigated how the quality and variability of these growth factors influence hPSC culture performance. To address this, we developed and applied multiple physicochemical characterization methods-including size exclusion and reverse-phase chromatography-to assess growth factor purity and identify impurities across different material sources. Our findings show that certain post-translational modifications in TGF-β (e.g., oxidized variants) did not measurably affect hPSC culture. However, high temperature-dependent instability of bFGF preparations significantly altered hPSC morphology and growth. These findings underscore the need for improved quality control of growth factor components in culture media to ensure consistent hPSC maintenance, thus decreasing variability across experiments. This study highlights the value of correlating analytical physicochemical data with process performance, thereby advancing material understanding, enabling more efficient process development, and facilitating the identification of critical material attributes that affect the quality of cell therapy products.