Utilizing Injection Molding to Generate Complex Three-Dimensional Cell Encapsulation Geometries

Encapsulation is a promising technology to deliver cell-based therapies to patients safely and with reduced need for immunosuppression. Macroencapsulation devices are advantageous due to their ease of retrieval, and thus enhanced safety profile, relative to microencapsulation techniques. A major challenge in macroencapsulation device design is ensuring sufficient oxygen transport to encapsulated cells, requiring high surface area-to-volume device geometries. In this work, a hydrogel injection molding biofabrication method was modified to design and generate complex three-dimensional macroencapsulation devices that have greater complexity in the z-axis. The rheological properties of diverse hydrogels were evaluated and used to perform computational flow modeling within injection mold devices to evaluate pressure regimes suitable for cell viability. 3D printed device designs were evaluated for the reproducibility of hydrogel filling and extraction. This work demonstrated that injection molding biofabrication to construct complex three-dimensional geometries is feasible in pressure regimes consistent with preserving cell viability. Future work will evaluate encapsulated cell viability after injection molding.