Exploring ethical, sustainable and effective foetal bovine serum alternatives for in vitro mammalian cell culture

Foetal bovine serum (FBS) has been widely used as a nutrient-rich supplement in mammalian cell culture for over 6 decades; however, its usage has increasingly raised various concerns and challenges related to quality variations, unethical collection practices, supply-demand imbalance and regulatory challenges. In recent years, alternatives have been investigated to reduce or replace FBS in mammalian cell culture. Starting from a comprehensive analysis of components of FBS and their functions in cell growth, this review compares the main types of FBS alternatives, i.e., human and animal-derived, plant-based alternatives and serum free media. Future perspectives discussed include the development of application-specific FBS alternatives, improvements in the quality and specialized formulation of FBS, optimization of existing alternatives and the establishment of databases and incentive mechanisms to facilitate the transition away from FBS. Lastly, the guidance for selecting appropriate FBS alternatives is also discussed.