| Bone defect and nonunion are still the dilemmas of reconstructive orthopedic surgery nowadays. Autograft, allograft and synthetic bone substitute materials play important roles in treating the problems, but they have their intrinsic disadvantages and cannot meet the demands in all situations. Autologous bone grafts are considered to be the golden standard against which the other skeletal substitutes are measured, as it owns both of the osteoinductive and osteoconductive properties and shows optimum skeletal incorporation without immune rejection, but the morbidity at donor sites, limited shape, size and amount of graft are the major drawbacks of the technique. Furthermore, the additional surgery makes patient undergo more injuries to body and more economic burden. Allogeneic bone material can be prepared into any shape, size needed in surgery without the limits of amount and kinds of bone, but the inevitable immune response and the risk of virus disease transmission make surgeons hesitate to choose it. In addition, the application of allogeneic bone material has to face a higher risk of infection and is more expensive. The implantation of synthetic bone substitute materials, such as Polymethylmethacrylate (PMMA), Polyether keton, Poly-Sulfone, Silastic sulphide, is mainly based upon their osteoconductive and structural properties. Their advantages includes that unrestricted material source, unlimited shape and size, and strong mechanical strength; their main disadvantage is absenting biodegradation properties, which will eventually lead to material failure by repeated mechanical loads of daylife activities due to absenting the incorporation with host bone tissue. Furthermore, as the materials are no vital and could not be revascularized, the risk of infection was higher than that of natural bone grafting.For the destination of overcoming the disadvantages of methods mentioned above, scholars in the medical field and biomaterial science field have focus much energy on the preparation of an ideal biomaterial to replace bone graft and to repair bone defect. An ideal bone repair biomaterial should meet the demands as following:(1) no cytotoxicity; (2) no or low immunogenicity; (3) bioresorbable and could be totally replaced by newly born bone tissue in relative short time; (4) could undergo mechanical stress needed in the implantedarea;(5) easy to prepare, preserve and purchase. The current main trendency of related research is to combine certain osteoinductive substances with certain osteoconductive carrier, which is called recombined artificial bone and is used to repair bone defect.In the present study, on the basis of review and analysis of the related literatures, we designed a preparation method, in which we combined the poly-dextrogyr, levogyr-lactic acid (PDLLA), hydroxyapatite (HA) and decalcified bone matrix (DBM) by emulsion blending method. The composite of PDLLA/HA/DBM was tested by a series of experiments in vitro and in vivo to observe its biocompatibility, osteoinductive and osteoconductive properties. The experiment was divided into four parts:1. A study on the preparation of PDLLA/HA/DBM and their physical, chemical characteristics and degradation characteristics in vitro. Emulsion blending method was used to prepare the PDLLA/HA/DBM composite, and the dynamic changes of weight, hydrophilicity and pH value was observed by degrading experiment in vitro, the pore diameter and rate of porosity of composite were measured by scanning electron microscopy.2. A study on the biocompatibility of PDLLA/HA/DBM coculture with human osteoblasts. Cocultured human osteoblasts were seeded on the PDLLA/HA/DBM composite, and morphological changes of osteoblasts were observed by light and scanning electon microscopy.3. Biological evaluation of PDLLA/HA/DBM composite. According to the demands of Technical Evaluation Standards of Biomedical Materials and Medical Instruments promulgated by Chinese Board of Health. Experiments of acute toxicity, pyrogen, hemolysis, implantation into muscles and post...
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