Steiner, Olivia2026-01-142026-01-142026-01-14http://hdl.handle.net/10393/51261https://doi.org/10.20381/ruor-316763D bioprinting holds promise for a broad range of tissue engineering applications, showing particular potential in the development of engineered articular cartilage grafts for treating cartilage injuries. However, the development of bioinks with optimal rheological, mechanical, and biological properties remains a significant challenge. Alginate is a commonly used bioink base polymer and is often prepared by pre-crosslinking with Ca²⁺ prior to extrusion-based bioprinting to improve its rheological properties and ensure an acceptable degree of shape fidelity. This study examines the use of alternative divalent cations as pre-crosslinking agents by evaluating and optimizing printability, shape fidelity, and cell viability. Cations with high binding affinities to alginate are found to improve the printability of bioinks. In particular, Sr²⁺ pre-crosslinked bioinks are found to support high chondrocyte viability and enhance the bioink's shape retention, yet lower the shear force required for flow, when compared to Ca²⁺. Constructs made with Sr²⁺ and Ca²⁺ pre-crosslinked bioinks were printed and post-crosslinked with either Sr²⁺ or Ca²⁺ for further evaluation. The Sr²⁺ pre-crosslinked bioinks are found to yield constructs that exhibit decreased degradation rates and increased mechanical strength independently of the choice of post-crosslinking cation and can support the accumulation of cartilage extracellular matrix by encapsulated chondrocytes. Analysis of cation retention finds that the pre-crosslinker is substantially replaced by the post-crosslinking agent, indicating that the pre-crosslinking agent may impact the construct properties and cell responses primarily through changes in the hydrogel microstructure. Taken together, the results of this study indicate that the choice of pre-crosslinker for alginate bioinks holds promise as a simple method of improving upon bioink shape fidelity and tuning bioprinted tissue construct properties.enCartilageThesis