Enzymatically degradable versatile hydrogel platform for cell sheet engineering

The structural organization of cells and their associated extracellular matrix (ECM) is critical to overall tissue function. Recapitulating the complex, highly organized structure of a target tissue is a key to achieve the unique functional characteristics of native tissue. However, achieving this goal requires a system in which substrate physicochemical properties such as modulus, topology and surface chemistry can be modulated. Here, we developed a cell sheet-based harvest & transfer system that can rapidly produce patterned 2D cell sheets in any physiologically relevant size and shape for various cell types. We further show that these cell sheets can be stacked one on top of the other with high cell viability while preserving the patterns, and that they remain sufficiently intact in vivo to allow neovascularization. We can thus use this system to mimic both the 2D and 3D structure of native tissue structure. A further advantage of our system is its substrate modulus tuning capability, which allows us to provide an optimal biomechanical environment for the differentiation and phenotypic stabilization of specific cell types. Because hydrogels theoretically have no limit in 2D shape and size, this system is scalable for producing quality controlled multiple cell sheets in a short period of time. Our model should also aid in understanding the mechanisms that underlie cell-cell and cell-ECM communication in 3D environments, which will be imperative to improving engineered tissue design. We thus ultimately envision that our system could allow the rapid fabrication of functionalized three dimensional thick tissues from multiple stacks of cell sheets derived from autologous cells, which would be an important step forward in both tissue modeling and regenerative medicine in general. Finally, this system can also potentially serve as a powerful model to study in vivo tissue formation and growth as well as cancer cell behavior