Tannic Acid-mediated Multifunctional 3D Printed Composite Hydrogel for Osteochondral Regeneration

Hydrogels have become an attractive option for tissue repair. A novel multifunctional hydrogel was developed using a two-step method involving photopolymerization and tannic acid (TA) solution incubation. The mechanical properties of this hydrogel were enhanced by the multi-hydrogen bond interaction between the TA and N-acryloyl glycinamide/gelatin methacrylate (NAGA/GelMA). The compressive modulus was doubled. The compressive strengths of the hydrogel were 5.5 MPa. The swelling rate was reduced by a factor of three. The adhesion strength of the composite hydrogel reached 80 KPa. The TA-mediated NAGA/GelMA/Laponite composite hydrogel exhibited excellent anti-fatigue and anti-oxidation properties, as well as printability. In vitro experiments indicated that the TA-mediated hydrogel facilitated the proliferation of bone marrow mesenchymal stem cells and osteogenic and chondrogenic differentiation. The developed multifunctional composite hydrogel has great potential for osteochondral defect repair under osteoarthritis conditions.