Investigation of oxidized alginate-gelatin-based hydrogels enriched with magnesium for cartilage tissue engineering

Cartilage is an aneural and avascular tissue with limited self-healing capacity, which requires external intervention upon injury. Since the 1990s, tissue engineering has emerged as a promising regenerative strategy, which can surpass the limitations of conventional treatments. Hydrogels, as highly hydrated polymer networks, are widely utilized in tissue engineering due to their structural and biochemical similarity to the native extracellular matrix (ECM). Among them, alginate dialdehyde-gelatin-based (ADA-GEL) hydrogels have gained attention for their biocompatibility and biodegradability. Recent studies have demonstrated that magnesium ions enhance chondral regeneration, yet their integration into ADA-GEL hydrogels remains unexplored. In this study, Mg 2+ -releasing ADA-GEL-based hydrogels were developed incorporating magnesium carbonate (MgCO 3 ) at concentrations ranging from 0.5 to 20 mg/mL, and the effect of the MgCO 3 concentration on resulting hydrogel properties was investigated comprehensively. Morphological analysis revealed suitable pore sizes of 100 – 300 μm across all formulations. Furthermore, increasing the MgCO 3 concentration led to improved mechanical properties and tailorable Mg 2+ ion release and hydrogel degradation in vitro . The investigation of cell-material interactions showed a beneficial effect of released Mg 2+ ions on the proliferation of chondrogenic ATDC5 cells, highlighting the potential of Mg 2+ enrichment of ADA-GEL-based hydrogels for cartilage tissue engineering approaches. • Alginate dialdehyde-gelatin (ADA-GEL)-based hydrogels investigated. • Mg 2+ -releasing ADA-GEL-based hydrogels developed incorporating MgCO 3 . • Increasing MgCO 3 concentration led to improved mechanical properties. • Mg 2+ ion release affected hydrogel degradation in vitro. • Beneficial effect of Mg 2+ ions on proliferation of chondrogenic cells confirmed.