Biomimicry of Cellular Interactions in 3D Stem Cell Scaffolds Via Proteolipobead-Matrix Hybrid Systems

Re-creation of the complex 3-D microenvironment of the stem cell niche in order to elicit regenerative control is one of the major challenges in biomaterials research. The overall aim of our effort is to test the hypothesis that the introduction of biomembrane-microsphere assemblies into 3D scaffolds is a viable biomimetic means to present ligands/bound factors to stem cells and mimic cellular communication in the stem cell niche. We have developed a new platform to present molecules to stem cells within a biomimetic architecture: as laterally-mobile molecules embedded in the context of a tailored biomembrane. The presentation of ligands/bound factors involved in cell-to-cell interactions (e.g. cadherin) has begun in 2D culture systems by surface patterning but has not yet been well established in 3D stem cell culture systems. We present results on three aspects of this study: 1) the fabrication and characterization of functionalized microspheres that contain supported lipid bilayers; 2) the construction and characterization of collagen-I/microsphere hybrid scaffolds that integrate tether-supported lipid bilayers on microspheres of various sizes and 3) preliminary studies of human MSCs microencapsulated into collagen-I/microsphere hybrid scaffolds.