Dynamic behavior and spontaneous differentiation of mouse embryoid bodies on hydrogel substrates of different surface charge and chemical structures.

Differentiation of embryoid bodies (EBs) into particular cell lineages has been extensively studied. There is an increasing interest in the effect of soft hydrogel scaffolds on the behavior of EBs, such as the initial adhesion, dynamic morphology change, and differentiation. In this study, without adding any other bioactive factors in the serum-containing medium, dynamic behaviors of mouse EBs loaded on the surface of hydrogels with different surface charge and chemical structures are investigated. EBs adhered quickly to negatively charged poly(sodium p-styrene sulfonate) (PNaSS) hydrogels, which facilitates EBs spreading, migration, and differentiation into three germ layers with high efficiency of cardiomyocytes differentiation, similar to that on gelatin coated polystyrene (PS) culture plate. While on neutral poly(acrylamide) (PAAm) hydrogels, EBs maintained the initial spherical morphology with high expression of pluripotency-related markers in the short culture periods, and then showed the significantly greater levels of selected endoderm markers after long-time culture. EBs cultured on negatively charged poly(2-acrylamido-2-methyl-propane sulfonic acid sodium salt) (PNaAMPS) gels demonstrated the analogous behaviors with that of neutral PAAm gels at early differentiation phase (day 4+1). Then, their adhesion, spreading and differentiation were quite similar to that on negatively charged PNaSS gels. The correlation between surface properties of hydrogels and EBs differentiation was discussed.