This study aims to investigate the effects of orthodontic expansion on graft area of a tissue-engineered bone (TEB) BMSCs/β-TCP, and to find an alternative strategy for the therapy of alveolar cleft. A unilateral alveolar cleft canine model was established and then treated with BMSCs/β-TCP under rapid maxillary expansion (RME). Sequential fluorescent labeling, radiography and helical computed tomography were used to evaluate new bone formation and mineralization in the graft area. Hematoxylin–eosin staining and Van Gieson׳s picro fuchsin staining were performed for histological and histomorphometric observation. ALP activity, mineralization and the expression of osteogenic differentiation related genes of BMSCs that grew on the β-TCP scaffold were promoted by their cultivation in osteogenic medium. Based on fact, TEB was constructed. After 8 weeks of treatment with BMSCs/β-TCP followed by RME, new bone formation and mineralization of the dogs were markedly accelerated, and bone resorption was significantly reduced, compared with the untreated dogs, or those only treated with autogenous iliac bone. The treatment with both TEB and RME evidently made the bone trabecula more abundant and the area of bone formation larger. What is more, there were no significant differences between BMSCs/β-TCP group and the group treated with autogenous bone and RME. This study further revealed that TEB was not only a feasible clinical approach for patients with alveolar cleft, but also a potential substituent of autogenous bone, and its combination with RME might be an alternative strategy for the therapy of alveolar cleft.

The efficacy of biomedical titanium implants mainly depends on their surface characteristics such as surface morphology, microstructure, and components, and the resulting performances. In this work, hierarchical hybrid micro/nanotip films incorporated with bioactive Sr2+/Mg2+ ions were prepared on a titanium surface by combining acid etching, hydrothermal treatment and a subsequent ion exchange process with Sr2+ and Mg2+ ions respectively. A Sr/Mg delivery platform is thus successfully obtained on a titanium surface and can allow for sustained release of Sr2+/Mg2+ ions at a slow rate for a period of time. In vitro SBF tests confirm that the Sr/Mg loaded titanate films possess good bioactivity accompanying the controlled release. Meanwhile, cell experiments further demonstrate that the Sr/Mg loaded micro/nanostructured titanium surfaces possess good biocompatibility and osteogenic activity. This is a successful attempt to apply an ion exchange technique to the surface modification of biomedical titanium materials and the strategy described here offers a general, facile, and straightforward chemical approach to functionalize various titanium-based material surfaces by constructing micro/nanostructures and using ion exchange with bioactive ions under mild synthetic conditions, and provides insight into the design of better biomedical implant surfaces for the future.

•Titanate films were prepared on Ti by acid etching and alkali treatment.•Proliferations of S. aureus and E. coli were effectively inhibited on films.•Proliferation of human RBE cells was significantly reduced on films.•Osteogenesis and angiogenesis of MSCs were remarkably enhanced on films.Many attentions have been paid to the beneficial effect of alkali-treated titanium to bioactivity and osteogenic activity, but few to the other biological effect. In this work, hierarchical micro/nanopore films were prepared on titanium surface by acid etching and alkali treatment and their biological effects on bacteria, cancer cells and mesenchymal stem cells were investigated. Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and human cholangiocarcinoma cell line RBE were used to investigate whether alkali-treated titanium can influence behaviors of bacteria and cancer cells. Responses of bone marrow mesenchymal stem cells (BMMSCs) to alkali-treated titanium were also subsequently investigated. The alkali-treated titanium can potently reduce bacterial adhesion, inhibit RBE and BMMSCs proliferation, while can better promote BMMSCs osteogenesis and angiogenesis than acid-etched titanium. The bacteriostatic ability of the alkali-treated titanium is proposed to result from the joint effect of micro/nanotopography and local pH increase at bacterium/material interface due to the hydrolysis of alkali (earth) metal titanate salts. The inhibitory action of cell proliferation is thought to be the effect of local pH increase at cell/material interface which causes the alkalosis of cells. This alkalosis model reported in this work will help to understand the biologic behaviors of various cells on alkali-treated titanium surface and design the intended biomedical applications.

To promote and understand the biological responses of the implant via nanostructured surface design is essential for the development of bioactive bone implants. However, the control of the surface topography of the bioceramics in nanoscale is a big challenge because of their brittle property. Herein, the hydroxyapatite (HAp) bioceramics with distinct nanostructured topographies were fabricated via hydrothermal treatment using α-tricalcium phosphate ceramic as hard-template under different reaction conditions. HAp bioceramics with nanosheet, nanorod and micro-nanohybrid structured surface in macroscopical size were obtained by controlling the composition of the reaction media. Comparing with the traditional sample with flat and dense surface, the fabricated HAp bioceramics with hierarchical 3D micro-nanotextured surfaces possessed higher specific surface area, which selectively enhanced adsorption of specific proteins including Fn and Vn in plasma, and stimulated osteoblast adhesion, growth, and osoteogenic differentiation. In particular, the biomimetic features of the hierarchical micro-nanohybrid surface resulted in the best ability for simultaneous enhancement of protein adsorption, osteoblast proliferation, and differentiation. The results suggest that the hierarchical micro-nanohybrid topography might be one of the critical factors to be considered in the design of functional bone grafts.Keywords: bone graft; hydroxyapatite; osteoblast; osteoinduction; protein adsorption; surface topography;

In present study, CaO–P2O5–SiO2-system mesoporous silica (MS) scaffolds were synthesized and loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2), while their protein release properties and other characteristics were investigated. Furthermore, rabbit bone marrow stromal cells (bMSCs) were cultured and seeded on rhBMP-2-loaded MS (rhBMP-2/MS) scaffolds. Cell adhesion and proliferation were evaluated by scanning electron microscopy (SEM) and MTT assays, while osteogenic differentiation was measured by ALP activity and real-time PCR analysis on the osteogenic markers of runt-related transcription factor 2 (Runx2), collagen type 1 (COL1), osteocalcin (OCN), and osteopontin (OPN). Finally, twenty-four rabbits received unilateral maxillary sinus floor elevation surgery at each time point (2 and 8 weeks), and randomly filled with one of the following four materials: MS alone; autologous bMSCs/MS complexes; rhBMP-2/MS complexes; or autologous bMSCs/rhBMP-2/MS complexes. New bone formation and mineralization were detected by histological/histomorphometric analysis, and fluorochrome labeling. The results showed that MS scaffolds presented excellent hierarchically large pore and well-ordered mesopore properties; moreover, rhBMP-2/MS scaffolds efficiently released rhBMP-2 in a sustained manner. Furthermore, rhBMP-2/MS scaffolds significantly enhanced the proliferation and osteogenic differentiation of bMSCs. In the maxillary sinus floor elevation experiments, rhBMP-2/MS scaffolds promoted new bone formation and augmented the height of the sinus floor, while the addition of bMSCs further enhanced new bone formation and mineralization. The present study revealed that CaO–P2O5–SiO2-system MS scaffolds could act as drug delivery carriers for rhBMP-2 and could be used to construct tissue-engineered bone with bMSCs for oromaxillofacial bone regeneration.Graphical abstractHighlights► Tissue-engineered bone constructed by rhBMP-2/MS scaffolds and bMSCs. ► bMSCs/rhBMP-2/MS complexes for oromaxillofacial bone regeneration. ► Pre-clinical evaluation of bone regeneration and material degradation for bMSCs/rhBMP-2/MS complexes.

This study evaluated the synergistic osteogenic effect of bone morphogenetic protein-2 (BMP-2) and Nel-like molecule-1 (Nell-1) genes in a rabbit maxillary sinus floor elevation model. Bone marrow stromal cells (bMSCs) were cultured and transduced with AdEGFP, AdNell-1, AdBMP-2, or AdNell-1 + AdBMP-2 overexpression virus. These gene-modified autologous bMSCs were then combined with a β-tricalcium phosphate (β-TCP) granule scaffold and used to elevate the maxillary sinus floor in rabbits. bMSCs cotransduced with AdNell-1 + AdBMP-2 demonstrated a synergistic effect on osteogenic differentiation as detected by real-time PCR analysis on markers of runt-related transcription factor-2, osteocalcin, collagen type 1, alkaline phosphatase activity, and calcium deposits in vitro. As for maxillary sinus floor elevation in a rabbit model in vivo, AdNell-1 + AdBMP-2 gene–transduced autologeous bMSCs/β-TCP complex had the largest bone area and most mature bone structure among the groups, as detected by HE staining and immunohistochemistry at weeks 2 and 8 after implantation. Our data suggested that the BMP-2 and Nell-1 genes possessed a synergistic effect on osteogenic differentiation of bMSCs, while bMSCs modified with the BMP-2 and Nell-1 genes could promote new bone formation and maturation in the rabbit maxillary sinus model.

The efficacy of biomedical titanium implants mainly depends on their surface characteristics such as surface morphology, microstructure, and components, and the resulting performances. In this work, hierarchical hybrid micro/nanotip films incorporated with bioactive Sr2+/Mg2+ ions were prepared on a titanium surface by combining acid etching, hydrothermal treatment and a subsequent ion exchange process with Sr2+ and Mg2+ ions respectively. A Sr/Mg delivery platform is thus successfully obtained on a titanium surface and can allow for sustained release of Sr2+/Mg2+ ions at a slow rate for a period of time. In vitro SBF tests confirm that the Sr/Mg loaded titanate films possess good bioactivity accompanying the controlled release. Meanwhile, cell experiments further demonstrate that the Sr/Mg loaded micro/nanostructured titanium surfaces possess good biocompatibility and osteogenic activity. This is a successful attempt to apply an ion exchange technique to the surface modification of biomedical titanium materials and the strategy described here offers a general, facile, and straightforward chemical approach to functionalize various titanium-based material surfaces by constructing micro/nanostructures and using ion exchange with bioactive ions under mild synthetic conditions, and provides insight into the design of better biomedical implant surfaces for the future.