Gelatin methacryloyl bioinks for bioprinting nasal cartilage: Balancing mechanical integrity and extracellular matrix formation

Gelatin methacryloyl (GelMA) is widely recognized as a versatile hydrogel, though few studies have examined its role in nasal cartilage engineering. In this study, we investigated how variations in GelMA concentration and lysyl oxidase-like 2 (LOXL2) supplementation would affect mechanical properties, extracellular matrix (ECM) deposition, and human nasoseptal chondrocyte remodeling in 3D bioprinted constructs. Using human serum-supplemented media to enhance clinical feasibility, we evaluated a Good Manufacturing Practices (GMP)-grade GelMA at 5, 10, and 15 % w/v. To improve mechanical properties, we investigated LOXL2's potential to enhance crosslinking of newly synthesized collagen, an approach not previously evaluated in gelatin biomaterials. After six weeks, higher GelMA concentrations increased stiffness, as demonstrated by suture pull-out, three-point bending, and compressive equilibrium moduli. However, improved mechanical performance accompanied a reduction in ECM deposition and elevated catabolic gene expression. These findings suggest that cells encapsulated in stiffer, more densely crosslinked constructs exhibited an altered anabolic-catabolic balance and chondrocyte behavior These results underscore the need to balance mechanical integrity with a microenvironment conducive to collagen synthesis and remodeling. By examining how GelMA concentration, crosslinking, and human serum-based conditions influence ECM deposition, this work advances macromolecular interactions in GelMA-based constructs in the development of clinically translatable cartilage grafts.