(165g) Engineering Auxetic Scaffolds for Human Stem Cell Differentiation

Negative Poisson Ratio (NPR) materials are one of the meta materials and attract high attention in biomedical applications. The auxetic materials (i.e. scaffolds that can display negative Poisson’s ratio) have high porosity, intendent resistance, shear resistance which are interesting properties in tissue engineering especially the vascular tissue regeneration. Polyurethane (PU) materials have been used recently as tissue engineering scaffolds. Due to the different ratios and categories of the components of di- or triisocyanate and polyol in PU, they have wide use for different tissue culture systems. Stem cells mechanosense the stiffness of their microenvironment, which impacts lineage commitment and differentiation. In addition, the high porosity can offer good transport of biomolecules for nutrient delivery and growth factor induction. In our experiments, five different auxetic PU foams were characterized as the scaffolds to investigate the behavior of human induced pluripotent stem cells (hiPSCs) on the materials. These scaffolds can be used with locally tunable force-displacement properties at length scales appropriate for tissue interaction. The surfaces of the foams were modified with chitosan, dopamine, heparin to enhance the adherence and proliferation of hiPSCs. Then, we investigate the vascular and neural differentiation of hiPSCs on different foams with distinct elastic modulus and Poisson’s ratio, which describes the degree of a material that contracts (or expands) transversally when axially strained. With different modulus of the foams, the cells showed different adherent density and different differentiation capacity. This approach represents a versatile and multifunctional scaffold fabrication and could lead to a suitable system for establishing hiPSCs culture models in the applications of disease modeling and drug screening.