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Bacterial infection poses a significant risk with the wide application of bone graft materials. Designing bone grafts with good antibacterial performance and excellent bone-forming activity is of particular significance for bone tissue engineering. In our study, a 3D printing method was used to prepare β-tricalcium phosphate (β-TCP) bioceramic scaffolds. Silver (Ag) nanoparticles were uniformly dispersed on graphene oxide (GO) to form a homogeneous nanocomposite (named Ag@GO) with different Ag-to-graphene oxide mass ratios, with this being synthesized via the liquid chemical reduction approach. Ag@GO nanocomposites were successfully modified on the β-TCP scaffolds by a simple soaking method to achieve bifunctional biomaterials with antibacterial and osteogenic activity. The prepared scaffolds possessed a connected network with triangle pore morphology and the surfaces of the β-TCP scaffolds were uniformly modified by the Ag@GO nanocomposite layers. The Ag content in the scaffolds was controlled by changing the coating times and concentration of the Ag@GO nanocomposites. The antibacterial activity of the scaffolds was assessed with Gram-negative bacteria (Escherichia coli, E. coli). The results demonstrated that the scaffolds with Ag@GO nanocomposites presented excellent antibacterial activity. In addition, the scaffolds coated with Ag@GO nanocomposites conspicuously accelerated the osteogenic differentiation of rabbit bone marrow stromal cells by improving their alkaline phosphatase activity and bone-related gene expression (osteopontin, runt-related transcription factor 2, osteocalcin and bone sialoprotein). This study demonstrates that bifunctional scaffolds with a combination of antibacterial and osteogenic activity can be achieved for the reconstruction of large-bone defects while preventing or treating infections.

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Hybrid hydrogels were fabricated via a new approach employing a dual enzyme-mediated redox initiation reaction and their applications for 3D printing and biocatalysis.

Magnetic scaffolds display prominent magnetothermal ability, and can effectively kill tumor cells in an alternating magnetic field and improve bone formation ability in vitro.

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Bioactive three-dimensional (3D) scaffolds play a key role in the repair or regeneration of large bone defects.There are many methods to prepare 3D scaffolds, among which the 3D-plotting technique is a promising strategy as the scaffolds prepared by this method possess not only improved mechanical properties and interconnectivity, but also ordered large-pore structure. However, the low cell attachment rate in the interior of the 3D-plotted scaffolds, especially for 3D-plotted bioceramic scaffolds, inhibits the osteogenesis of stem cells in the scaffolds both in vitro and in vivo. The aim of this study is to prepare hierarchically porous composite scaffolds in order to improve the cell attachment, and further stimulate the in vitro and in vivo osteogenesis. We successfully fabricated hierarchically porous bioceramic-silk (BC-silk) composite scaffolds by a combination of the 3D-plotting technique with the freeze-drying method, and further investigated the attachment, proliferation and osteogenic differentiation of bone marrow stromal cells (BMSCs) in the scaffolds as well as the in vivo osteogenesis of the prepared porous scaffolds. The results showed that the hierarchical structure in the composite scaffolds was composed of first-level pores (B1 mm) of the bioceramic scaffold and second-level pores (B50-100 mm) of the silk matrix. The prepared BC-silk composite scaffolds possessed excellent apatite-mineralization ability and mechanical properties with compressive strength up to 25 MPa. In addition, hierarchically porous BC-silk scaffolds presented significantly enhanced attachment rate of BMSCs, around 4 times that of pure BC scaffolds without hierarchical pore structures. BC-silk scaffolds with hierarchical pore structures showed distinctively improved cell proliferation, ALP activity and bone-related gene expression as compared to BC scaffolds without hierarchical pore structure. Furthermore, hierarchically porous BC-silk scaffolds significantly enhanced the formation of new bone in vivo as compared to BC scaffolds. Our results suggest that the combination of 3D-plotting with the freeze-drying method is a viable strategy to construct hierarchical pore structures in 3D-plotted scaffolds, and the hierarchical pore structure plays an important role in improving the in vitro and in vivo osteogenesis of 3D-plotted bioceramic scaffolds for bone regeneration application.