3D Printed Gelatin/Sodium Alginate Hydrogel Scaffolds Doped with Nano-Attapulgite for Bone Tissue Repair

Chun Liu,1 Wen Qin,1 Yan Wang,2 Jiayi Ma,1 Jun Liu,1 Siyu Wu,1 Hongbin Zhao1 1Medical Research Centre, Changzhou Second People’s Hospital Affiliated to Nanjing Medical University, Changzhou, 213164, People’s Republic of China; 2Department of Clinical Laboratory, Changzhou Second People’s Hospital Affiliated to Nanjing Medical University, Changzhou, 213164, People’s Republic of ChinaCorrespondence: Hongbin ZhaoMedical Research Centre, Changzhou Second People’s Hospital Affiliated to Nanjing Medical University, No. 68, Gehu Road, Changzhou, Jiangsu, 213164, People’s Republic of ChinaTel/Fax +86 13919761032Email zhao761032@163.comIntroduction: Bone tissue engineering (BTE) is a new strategy for bone defect repair, but the difficulties in the fabrication of scaffolds with personalized structures still limited their clinical applications. The rapid development in three-dimensional (3D) printing endows it capable of controlling the porous structures of scaffolds with high structural complexity and provides flexibility to meet specific needs of bone repair.Methods: In this study, sodium alginate (SA)/gelatin (Gel) hydrogel scaffolds doped with different contents of nano-attapulgite were fabricated via 3D printing. The surface microstructure, hydrophilicity and mechanical properties were fully evaluated. Furthermore, mouse bone marrow-derived mesenchymal stem cells (BMSCs) were cultured with the composite hydrogels in vitro, and proliferation and osteoblastic differentiation were assessed. A rabbit tibia plateau defect model was used to evaluate the osteogenic potential of the composite hydrogel in vivo.Results: When increasing nano-ATP content, the Gel/SA/nano-ATP composite hydrogels showed better mechanical property and printability. Moreover, Gel/SA/nano-ATP composite hydrogels showed excellent bioactivity, and a significant mineralization effect was observed on the surface after being incubated in simulated body fluid (SBF) for 14 days. The Gel/SA/nano-ATP composite hydrogel also showed good biocompatibility and promoted the osteogenesis of BMSCs. Finally, histological analysis demonstrates that the Gel/SA/nano-ATP composite hydrogels could effectively enhance bone regeneration in vivo.Conclusion: These properties render the Gel/SA/nano-ATP composite hydrogel scaffolds an ideal bone tissue engineering material for the repair of bone defects.Keywords: 3D printing, attapulgite, composite hydrogel, osteogenesis, bone repair