3D Printing of genipin crosslinked alginate/gelatin Ink for tissue engineering application

Tissue engineering demands scaffolds that replicate the extracellular matrix to foster cell growth and tissue regeneration. This study introduces a novel 3D-printable bioink formulated from a composite of 7 % gelatin and 9 % alginate, crosslinked with genipin, a naturally derived, low-toxicity agent at concentrations of 0 %, 0.1 %, 0.5 %, and 1 %. Optimized for extrusion-based 3D printing at 15 °C, the bioink achieved excellent shape fidelity, enabling the fabrication of mechanically robust and biologically supportive scaffolds. Physicochemical characterization revealed that genipin crosslinking enhanced the compressive modulus (up to 0.023 MPa at 1 % genipin) and degradation resistance, though higher concentrations reduced the swelling ratio. Biological evaluations with human dermal fibroblasts demonstrated superior cell viability (>100 %) and cell adhesion at 0.1 % and 0.5 % genipin; while 1 % genipin decreased cell adhesion and viability to 81 % and impaired hemocompatibility (>5 % hemolysis). These findings highlight the tunable characteristics of genipin-crosslinked alginate/gelatin hydrogels, offering a versatile platform for engineering functional tissue constructs with balanced mechanical and biological properties, suitable for advanced tissue engineering applications.