Implantation of synthetic materials into body elicits inflammatory host responses that limit medical device integration and biological performance. Since the effective use of biomaterials in vivo requires good biocompatibility and bio-functionality, it is vital that we assess the inflammatory reactions provoked by various implanted biomaterials. In chemical precipitation of β-tricalcium phosphate [β-Ca₃(PO₄)₂, β-TCP], the impurity of calcium pyrophosphate (Ca₂P₂O₇, CPP) will easily appear if the preparation conditions are not well controlled. To test the influences of CCP-impurity on the biocompatibility of the material, four groups of β-TCP ceramic samples doped with 0.5–10 wt % of CCP impurity, and pure β-TCP and CCP samples were fabricated and implanted in rat subcutaneous site for one, two, and four weeks. The host tissue responses to the ceramics were evaluated by histomorphometric analysis, and the results were compared with pure β-TCPbioceramics. The results show that the CPP impurity can elicit and stimulate the inflammatory responses at the tissue/implant interface. Moreover, with the increase of CPP doping amount, the inflammation increases apparently. However, the pure β-TCP bioceramics only present slight post-implantation inflammatory responses. The influence of the CPP doping on the inflammatory responses is mainly related to a microparticles release because of an insufficient sintering of β-TCP by CPP doping. The microparticle release could be at the origin of local inflammation and cell/tissue damages. Therefore, to obtain perfect biocompatibility and high quality β-TCP bioceramics, it is important to avoid and control the CPP impurity in the preparation of β-TCP powders and bioceramics. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.

Segmental bone defect resulted from trauma or excision of bone tumor or pathology represents a common and significant clinical problem. In an attempt to solve this dilemma, we use β-TCP combined with autologous bone marrow mesenchymal stem cells (auto-BMSC) and cultured by dynamic perfusion to repair the segmental bone defects of goat's tibia. The β-TCP scaffolds combined with auto-BMSC by dynamic perfusion bioreactor or in static state were respectively transplanted into the defect (30 mm) of the goat tibias. The X-ray films were gathered and analyzed at the different time points. At 24 weeks post-operation, tissue engineering bones implanted were analyzed by histology and Micro-CT. Results show that the capacity of osteogenesis in experimental group was higher than that of control group by X-ray, histological, and micro-CT analysis (p < 0.05). According to the study, we found that repair for segmental bone defects of tissue engineering bone cultured by dynamic perfusion culture bioreactor outweigh those cultured in static state. And we can conclude that this technology of tissue engineering bone will become a clinical method to the segmental bone-defects repair in the future. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010

One unsolved problem in bone tissue engineering is how to enable the survival and proliferation of osteoblastic cells in large scaffolds. In this work, large β-tricalcium phosphate scaffolds with tightly controlled channel architectures were fabricated and a custom-designed perfusion bioreactor was developed. Human fetal bone cells in third passage were seeded onto the scaffolds and cultured in static or flow perfusion conditions for up to 16 days. Compared with nonperfused constructs, flow perfused constructs demonstrated improved cells proliferation and differentiation according to cell viability, glucose consumption, alkaline phosphatase activity, and osteopontin. Moreover, after 16 days of perfusion culture, a homogenous layer composed of cells and mineralized matrix throughout the whole scaffold was observed by scanning electron microscopy and histological study. In contrast, cells were located only along the scaffold perimeter in static culture. These results demonstrated the feasibility and benefit of perfusion culture in conjunction with well-defined three-dimensional environment for large bone graft construction. Porous scaffold with controlled architecture can be a potential tool to evaluate the effects of scaffold specific geometry on fluid flow configuration and cell behavior under perfusion culture. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009