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

Abstract

Introduction 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.

Synergistic effects of nanoattapulgite and hydroxyapatite on vascularization and bone formation in a rabbit tibia bone defect model

“…Our recent study found that when increasing the ATP content, gelatine/sodium alginate/ATP composite hydrogels showed better mechanical properties. 54 To enhance the mechanical properties of the typical HA scaffold, a novel nanocomposite bioscaffold was prepared by introducing ATP nanoparticles. In this study, rheological analysis revealed that the biomaterial ink exhibited shear-thinning behaviour.…”

“…In addition, the incorporation of ATP increased the viscosity of the printing ink, which was beneficial for retaining their predefined size and improved the shape fidelity of the scaffolds. 52,54 The compressive strength was significantly improved in the PC-A, PC-A2H1, and PC-A1H1 groups compared with the PC-H groups in the wet state. On one hand, the observed mechanical behaviour could be attributed to the fibrillar structure and surface effect of the ATP nanoparticles.…”

Novel Approaches and Biomaterials for Bone Tissue Engineering: A Focus on Silk Fibroin

“…Several three-dimensional printing technologies incorporating cells in the scaffold structure during the fabrication process have also attracted great interest. These techniques involve a number of variables in their processing approaches, which influence the characteristics of the fabricated bone scaffolds [ 44 ] and allow the control of the porous structures of scaffolds with high structural complexity [ 45 ].…”

“…A composite hydrogel scaffold was developed by Liu et al through 3D printing by using sodium alginate and gelatin doped with different amounts of nano-attapulgite. The composite system demonstrated good biocompatibility and improved mechanical properties compared to the gel without nano-attapulgite, osteogenesis differentiation of BMSCs and bone regeneration capability in vivo [ 45 ]. Better osteogenesis and osseointegration was also associated to systems based on hyaluronic acid (HA) hydrogels and microparticles, which can covalently bind to metal implants and release bioactive molecules [ 5 ], and much effort has been made in developing HA hydrogel systems for applications in bone tissue engineering both in vitro and in vivo [ 19 ].…”

“…Indeed, although a large number of materials have been fabricated for bone regeneration and significant progress continues to be made, only a very limited number of scaffolds have been clinically used [ 41 , 126 , 128 ]. The difficulties in fabricating scaffolds with personalized structures can also limit their clinical applications [ 45 ], along with the inappropriate osteogenic differentiation, vascularization and growth factor delivery exhibited by some techniques [ 11 ]. In the production of large bone constructs, many factors such as vascularization, identification of appropriate mechanical stimuli, tuning of bioactive agent release and osteointegration require optimization studies supported by substantial clinical experiences [ 3 , 17 ].…”