Microcarrier-based stem cell bioprocessing: GMP-grade culture challenges and future trends for regenerative medicine

Recently, stem cell-based therapies have been proposed as an alternative for the treatment of many diseases. Stem cells (SCs) are well known for their capacity to preserve themselves, proliferate, and differentiate into multiple lineages. These characteristics allow stem cells to be a viable option for the treatment of diverse diseases. Traditional methodologies based on 2-dimensional culture techniques (T-flasks and Petri dishes) are simple and well standardized; however, they present disadvantages that limit the production of the cell yield required for regenerative medicine applications. Lately, microcarrier (MC)-based culture techniques have emerged as an attractive platform for expanding stem cells in suspension systems. Although the use of stem cell expansion on MCs has recently shown significant increase, their implementation for medical purposes is been hampered by bottlenecks in upstream and downstream processing. Therefore, there is an urgent need in the development of bioprocesses that simplify stem cell cultures under xeno-free conditions and detachment from MCs without diminishing their pluripotency and viability. A critical analysis of the factors that impact the up and downstream bioprocessing on MC-based stem cell cultures is presented in this review. This analysis aims to raise the awareness of the current drawbacks that limit MC-based stem cell bioprocessing in regenerative medicine and propose alternatives to overcome them.