Engineering scalable immobilized cell culture systems for diabetes cellular therapy

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Advances in stem cell research and tissue engineering have led to the development of complex three-dimensional (3D) tissue constructs that hold great promise for disease modelling as well as tissue replacement. The long-term goal of this research program is to develop scalable therapeutic cell production and transplantation systems, in particular for diabetes cellular therapy. The 5-year goal of this program is to optimize methods for hydrogel immobilized culture of islet-like cell clusters (ILCs). The specific aims of the 5-year program are to (1) microencapsulate ILCs by microchannel emulsification, (2) generate vascularized ILC-containing constructs, (3) optimize vessel geometries based on oxygen mass transfer models and (4) study the effects of oxygen tension and vascular cells on ILC differentiation. First, a highly scalable microchannel emulsification process developed in my laboratory will be adapted to better control bead residence time in acidified oil. After assessing cell survival and function, the microencapsulated ILCs will be cultured in vascularized cm scale tissue constructs as a potential macroencapsulation system. These vascular channels will be generated through embedded writing of sacrificial materials into ILC-containing hydrogel support matrices. To do so, a fugitive bioink will be 3D printed into the support matrix material, which will be selected based on its vasculogenic potential, mechanical properties and print fidelity. After gelation of the support matrix, the fugitive ink will be evacuated to create hollow channels. Following ILC survival and functional assessment, the resulting tissue constructs will be cultured under perfusion for several weeks to allow ILC maturation. To optimize vascular lattice geometries, a numerical model predicting oxygen tension profiles in constructs of different configuration will be developed. Model predictions will be compared to experimental oxygen concentration profiles determined using a paramagnetic oxygen-sensitive probe. These studies will be conducted with or without adding vascular endothelial cells into the vasculogenic support matrix to study their interactions with the ILCs. These studies will pave the way towards engineering a vascularized bioartificial pancreas used for in vitro drug testing as well as eventual transplantation. The proposed research program provides fertile grounds for training highly qualified personnel, which includes 3 PhDs, 1 Master's and 5 undergraduate trainees. This research program is expected to have far-reaching impact on the biomedical community and the health of Canadians. Translation of the research findings will be accelerated by existing collaborations with industry and clinicians.