Three-Dimensional Spheroid Culture on Polymer-Coated Surface Potentiate Stem Cell Functions via Enhanced Cell-Extracellular Matrix Interactions

The aggregation of mesenchymal stem cells (MSCs) into three-dimensional (3D) spheroids has emerged as a promising therapeutic candidate for the treatment of a variety of diseases. In spite of the numerous 3D culture methods suggested recently for MSC spheroid generation, it is still elusive to fully reflect real stem cell niches; this effort majorly suffers from a lack of cell-extracellular matrix (ECM) interactions within the 3D spheroids. In this study, we develop a simple but versatile method for generating human MSC (hMSC) spheroids by culturing the cells on a functional polymer film surface, poly(2,4,6,8-tetravinyl-2,4,6,8-tetramethyl cyclotetrasiloxane) (pV4D4). Interestingly, the pV4D4-coated surface allows a dynamic cell adhesion to the polymer surface while developing the formation of 3D spheroids. The corresponding mechanotransduction promotes the expression of the endogenous ECM and, in turn, results in a remarkable improvement in self-renewal abilities, pro-angiogenic potency, and multilineage differentiation capabilities. This observation highlights the significance of our method compared to the conventional spheroid-generating methods in terms of recreating the ECM-rich microenvironment. We believe the developed surface can serve as a versatile but reliable method for stem cell-based tissue engineering and regenerative medicine.