(746a) Mixing-Induced Gelation of Protein-Biomaterials for Cell Encapsulation

Three-dimensional culture platforms are essential to the maintenance of native cell characteristics in vitro. For common biomatrices such as Matrigel and collagen, cell encapsulation involves gel formation by non-physiological environmental triggers (temperature and pH sweeps), while cell recovery requires gel disassembly by harsh enzymatic digestion. Both of these processes are detrimental to encapsulated cells and proteins. To address this, we have designed two-component physical hydrogels that undergo gelation under constant physiological conditions. The two components contain recombinantly engineered protein polymers of the WW domain and its proline-rich ligand, which associate upon mixing. Furthermore, the addition of proline-rich peptide monomers initiates competitive binding and gel dissolution, facilitating non-enzymatic cell recovery. A variety of cell types including murine neural progenitor cells, murine mesenchymal stem cells, and human adipocyte stem cells demonstrate excellent viability, proliferation, and differentiation within the 3D gels. The viscoelastic properties of the gels can be tailored using simple polymer physics considerations, making them ideal candidates for 3D mechanotransduction studies. In addition, these shear-thinning and self-healing gels are being evaluated as injectable cell-carrier matrices for regenerative medicine therapies.