Fabrication and characterization of 3D printed agarose/poly(ethylene glycol) diacrylate/hydroxyapatite nanocomposite hydrogel for cartilage tissue engineering.

Damage to the articular cartilage can be caused by osteoarthritis (OA), exercise, cancer, and etc. A major challenge is cartilage's limited ability to self-repair after injury. In this study, the new cartilage scaffold was prepared by two biocompatible materials, agarose and poly(ethylene glycol) diacrylate (PEGDA), using a 3D printer. In this work used Taguchi-based statistical optimization to determine the optimal agarose concentration for 3D scaffolds. A key innovation was the incorporation of nanohydroxyapatite (nHA), which improved the hydrogel's viscosity and shear-thinning behavior, printability, and mechanical performance compared to agarose/PEGDA hydrogel. The effect of different concentrations of nHA on the physical, mechanical, and structural properties of the scaffold was investigated using a rheometer, fourier transform spectroscopy, field emission scanning electron microscope, X-ray diffraction, and mechanical tests. In vitro swelling and degradation tests showed that nHA enhanced hydrogel stability by reducing swelling and degradation rates from 291 % to 176 % after 24 h and from 66 % to 60 % after 14 days, respectively, improving durability for long-term applications. The scaffolds showed remarkable biocompatibility, with L929 cells adhering and proliferating at a non-toxicity rate of 95.6 % after 5 days. These results suggest that agarose/PEGDA/nHA hydrogel scaffolds offer a promising, engineered, stable, and biocompatible solution for cartilage regeneration.