Defining the Surface Chemistry for Pluripotent Stem Cell Culture on 2D and 3D Porous Substrates

Surface chemistry is critical for growing pluripotent stem cells in an undifferentiated state and expanding them in large number of cells.  The challenge is to identify the optimal surface chemistry of the substrata for pluripotent stem cell attachment and maintenance.  Using a high-throughput polymerization and screening platform, a chemically defined, synthetic polymer grafted coating that supports strong attachment and high expansion capacity of pluripotent stem cells has been discovered using mouse embryonic stem (ES) cells as a model system.  This optimal substrate, N-[3-(Dimethylamino)propyl] methacrylamide (DMAPMA), sustains long-term self-renewal of ES cells.  DMAPMA supports cell attachment of ES cells through integrin β1 in a RGD-independent manner and is similar to another recently reported polymer surface.  The results obtained on a 2-D porous flat sheet membrane were then transferred to 3D by grafting DMAPMA to synthetic poly(ether sulfone) (PES) fibrous matrices through both photo-induced and plasma-induced polymerization.  These 3D modified fibers exhibited higher cell proliferation and greater expression of pluripotency markers of mouse ES cells than 2D PES porous membranes.  Our results indicated that desirable surfaces in 2D can be scaled to 3D and that both surface chemistry and structural dimension strongly influence the growth and differentiation of pluripotent stem cells.