Microcarriers with synthetic hydrogel surfaces for stem cell expansion

摘要

Microcarriers are scalable support surfaces for cell growth that enable high levels of expansion, and are particularly relevant for expansion of human mesenchymal stem cells (hMSCs). The goal of this study was to develop a poly(ethylene glycol) (PEG)-based microcarrier coating for hMSC expansion. Commercially available microcarriers do not offer customizability of microcarrier surface properties, including elastic modulus and surface cell adhesion ligands. Our lab has previously demonstrated that tuning these material properties on PEG-based hydrogels can modulate important cellular growth characteristics, such as cell attachment and expansion, which are important in microcarrier-based culture. Eosin-Y was adsorbed to polystyrene microcarriers and used as a photoinitiator for thiol-ene polymerization under visible light. Resultant PEG coatings were over 100 µm thick and localized to microcarrier surfaces. This thickness is relevant for cells to react to mechanical properties of the hydrogel coating, and coated microcarriers supported hMSC attachment and expansion. hMSC expansion was highly favorable on coated microcarriers in serum-free media, with doubling times under 25 hours in the growth phase, and retained osteogenic and adipogenic differentiation capacity after culture on microcarriers. These microcarriers with defined, synthetic coatings enable tailorable surfaces for cell expansion that may be suitable for a variety of biomanufacturing applications.