Screening for 3D environments that support human mesenchymal stem cell viability using hydrogel arrays.

In this study we generated 3D poly(ethylene glycol) (PEG) hydrogel arrays to screen for the individual and combinatorial effects of extracellular matrix (ECM) degradability, cell adhesion ligand type, and cell adhesion ligand density on human mesenchymal stem cell (hMSC) viability. In particular, we explored the influence of two well-characterized ECM-derived cell adhesion ligands: the fibronectin-derived Arg-Gly-Asp-Ser-Pro (RGDSP) sequence, and the laminin-derived Ile-Lys-Val-Ala-Val (IKVAV) sequence. PEG network degradation, the RGDSP ligand, and the IKVAV ligand each individually increased hMSC viability in a dose-dependent manner. The RGDSP ligand also improved hMSC viability in a dose-dependent manner in degradable PEG hydrogels, while the effect of IKVAV was less pronounced in degradable hydrogels. Combinations of RGDSP and IKVAV promoted high viability of hMSCs in nondegradable PEG networks, while the combined effects of the ligands were not significant in degradable PEG hydrogels. Although hMSC spreading was not commonly observed within PEG hydrogels, we qualitatively observed hMSC spreading after 5 days only in degradable PEG hydrogels prepared with 2.5 mM of both RGDSP and IKVAV. These results suggest that the enhanced throughput approach described herein can be used to rapidly study the influence of a broad range of ECM parameters, as well as their combinations, on stem cell behavior.