Special Poster Session Biofabrication
3D bioprinting is a promising and innovative technique in the field of tissue engineering allowing the generation of highly precise constructs for different purposes. During that process, cells are facing different challenges to survive in the hydrogel environment. Our project investigates shear stress impact as well as adherence behavior of human mesenchymal stromal cells (hMSC) in biofabrication processes and aims to enhance the glycocalyx mediated cell stability and the lectin ligand mediated adhesion in bioinks by applying glycoengineering.
For establishing metabolic glycoengineering, hMSC were first incubated with different azido sugars for 48 h followed by click-reactions in which cells were either incubated with DBCO-Cy3 as click molecule for 1 h or in presence of Cu ions with alkyne-Cy3 for 5 min. The fluorescence of the resulting dye-sugar complex was microscopically evaluated over time. For galectin-1 binding studies, cells were incubated with an artificial galectin-1 ligand or seeded onto a ligand coated glass slide.
The azido sugar expression in the glycocalyx could be microscopically detected up to 48 h identifiying the mannosamine variant as superior regarding cell viability and incorporation efficiency. The glycochip assay resulted in the appearance of non-adherent cell spheroids, but revealed no cell adhesion toward the galectin-1 ligand coated regions. A first galectin-1 gene expression analysis showed no remarkably altered mRNA level after incubation with the ligand.
Since the metabolic glycoengineering is working, suitable molecules can now be identified to be introduced into the glycocalyx and evaluated for cell rigidity-increasing effects before and after 3D bioprinting. To support data interpretation, the shear stress impact on cell features after printing will be characterized before with unmodified cells. The adherence assay needs to be redesigned since cell adhesion was expected and the glycochip basic functionalization might impede surface-cell interaction. The galectin-1 ligand impact on cell functions will be further characterized.