3D-printed bioactive ceramic scaffolds with biomimetic micro/nano-HAp surfaces mediated cell fate and promoted bone augmentation of the bone–implant interface in vivo

Calcium phosphate bio-ceramics are osteo-conductive, but it remains a challenge to promote the induction of bone augmentation and capillary formation. The surface micro/nano-topography of materials can be recognized by cells and then the cell fate are mediated. Traditional regulation methods of carving surface structures on bio-ceramics employ mineral reagents and organic additives, which might introduce impurity phases and affect the biological results. In a previous study, a facile and novel method was utilized with ultrapure water as the unique reagent for hydrothermal treatment, and a uniform hydroxyapatite (HAp) surface layer was constructed on composite ceramics (β-TCP/CaSiO₃) in situ. Further combined with 3D printing technology, biomimetic hierarchical structure scaffolds were fabricated with interconnected porous composite ceramic scaffolds as the architecture and micro/nano-rod hybrid HAp as the surface layer. The obtained HAp surface layer favoured cell adhesion, alleviated the cytotoxicity of precursor scaffolds, and upregulated the cellular differentiation of mBMSCs and gene expression of HUVECs in vitro. In vivo studies showed that capillary formation, bone augmentation and new bone matrix formation were upregulated after the HAp surface layer was obtained, and the results confirmed that the fabricated biomimetic hierarchical structure scaffold could be an effective candidate for bone regeneration.

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Simple and practical process to construct surface structure layer in situ with little impurities.

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Combined with the 3D printing technology to fabricate architecture of the pre-treated matrix.

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Study the angiogenesis and osteogenesis (for mesenchymal stem cells) separately.

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Improving tissue growth in vivo: capillary formation, bone-augmentation and new bone matrix formation.

Three-Dimensional Printing of Large-Scale, High-Resolution Bioceramics with Micronano Inner Porosity and Customized Surface Characterization Design for Bone Regeneration

Three-dimensional printing technologies have opened up new possibilities for manufacturing bioceramics with complex shapes in a completely digital fabrication process. Some bioceramics have demonstrated elaborate design and high resolution in their small parts through digital light projection (DLP) printing. However, it is still a challenge to prepare large-scale, high-precision ceramics that can effectively regulate the bioactivity of materials. In this study, we fabricated a large-scale hydroxyapatite porous bioceramic (length >150 mm) using DLP. This bioceramic had highly micronanoporous surface structures (printing resolution <65 μm), which could be controlled by adjusting the solid content and sintering process. Both in vitro and in vivo results indicated that the designed bioceramic had promising bone regeneration ability. This study provides significant evidence for exploring the effects of microenvironments on bone tissue regeneration. These results indicated that DLP technology has the potential to produce large-scale bone tissue engineering scaffolds with accurate porosity.