Temperature-independent and photocrosslinkable hydrolyzed GelMA with tunable mechanics for biofabrication

Thermoresponsive and photo-crosslinkable hydrogels are highly desirable for biofabrication; however, conventional gelatin methacryloyl (GelMA) exhibited thermal gelation below 30 °C and high viscosity, restricting its compatibility with concentration-dependent tunability and lower critical solution temperature-type systems. To address these issues, hydrolyzed GelMA (hGelMA) was developed by subjecting GelMA to controlled enzymatic degradation, effectively eliminating thermal gelation while maintaining photo-crosslinkability and enabling broader control of the mechanical properties through concentration adjustment. The resulting hGelMA was characterized for viscosity, mechanical tunability, and compatibility with digital light processing bioprinting. Cell compatibility was evaluated, and the ability of hGelMA to integrate with thermoresponsive hydrogels, such as hydroxybutyl-methacrylated chitosan, was assessed to demonstrate its suitability for composite bioink systems. hGelMA showed significantly reduced viscosity, supported high-resolution digital light processing bioprinting across a wide stiffness range, and maintained excellent cell compatibility. In addition, its temperature-independent behavior facilitated its integration with thermoresponsive hydrogels exhibiting lower critical solution temperature (LCST) behavior, thereby broadening its potential for composite bioink systems. These findings indicate that hGelMA could serve as a practical and adaptable material for use in bioink formulations for tissue engineering and bioprinting applications.