Development and Characterization of Crosslinked Collagen Biomaterial Inks for 3D Bioprinting Applications.

Abstract

Tissue engineering faces significant challenges due to limited organ availability and transplantation risks. This study developed and characterized crosslinked collagen bioinks extracted from calf skin for 3D bioprinting applications. Collagen was extracted using pepsin digestion and purified through dialysis. Bioinks were prepared at 3%, 4%, and 5% (w/v) concentrations and crosslinked using genipin (1, 3, 5 mM) and riboflavin (1 mM) with UV-A activation. Optimal printing parameters were determined as 5% (w/v) collagen concentration with 0.26 mm nozzle diameter. Synchrotron FTIR spectroscopy confirmed successful crosslinking through characteristic peak shifts in amide regions. Mechanical testing revealed enhanced compressive strength: riboflavin-crosslinked scaffolds (1.5 ± 0.08 MPa) > genipincrosslinked scaffolds (1.19 ± 0.12 MPa) > uncrosslinked scaffolds (0.66 ± 0.03 MPa). Cell viability assessments using fibroblasts showed that 1 mM genipin crosslinking increased cell viability to 181.2 ± 29.32% compared to uncrosslinked controls, while higher genipin concentrations (3 mM) reduced viability to 62.10 ± 15.74%. Riboflavin crosslinking maintained biocompatibility with 130.43 ± 166.26% cell viability. These results demonstrate that both crosslinking agents successfully enhance mechanical properties while maintaining biocompatibility, with optimal parameters dependent on specific application requirements for tissue engineering scaffolds.