BACKGROUND:In general, a single-type artificial bone is difficult to meet the requirements for bone defect repair and extracellular matrix of bone tissue engineering. Compositing and processing the materials with different properties can form the composite-type artificial bone, which can either ensure the biological activity or effectively improve its mechanical properties.OBJECTIVE: To summarize the present situation of the application of composite-type artificial bone and prospects the development trend. METHODS:The literatures were retrieved from CNKI, ScienceDirect, PubMed, SpingerLink, El Village, Wiley databases from January 2000 to April 2017. The key words were "composite scaffold, tissue engineering, artificial bone" in Chinese and English, respectively. The selected literatures were analyzed according to the inclusion and exclusion criteria. RESULTS AND CONCLUSION: The requirements for the scaffolds used for bone tissue engineering are complex and it should carefully consider and control various factors used in the design and preparation of scaffolds, including microporous structure, mechanical strength, degradation rate, porosity, growth factor, morphology and surface chemistry, so as to meet the bone tissue engineering applications. The preparation of tissue-engineered bone scaffold is based on biological active substances and matrix materials through a reasonable manner. It simulates the components of natural bone matrix, promotes the adhesion, proliferation and differentiation of bioactive substances, and gives play to its functions of osteogenesis. Although existing techniques and methods have made significant progress in the preparation of composite scaffolds, there is no technique or method to fully meet all the requirements for preparation of tissue-engineered bone scaffold.

Objective To analyze the influence of microporous parameters on mechanical behavior of bone tissue engineered-scaffolds, and provide references for optimizing the microporous structure design. Methods The finite element models of scaffolds with microporous structures were established by using ANYSYS software. The relationships between porosity and maximum equivalent stress as well as maximum total deformation were calculated. The effects of microporous spacing and diameter on maximum equivalent stress, maximum total deformation and internal strain were compared and analyzed. Results The influence rule of microporous spacing in x and y direction was consistent. With the increase of microporous spacing from 0.6 mm to 2.0 mm, the maximum equivalent stress reduced from 63.1 MPa to 46.3 MPa, the maximum total deformation reduced from 23.8 μm to 21.8 μm, and the proportion of the best strain range increased from 80% to 84%. However, with the increase of microporous spacing in z direction, the maximum equivalent stress increased from 38.3 MPa to 47.8 MPa, the maximum total deformation increased from 20. 8 μm to 22.8 μm, and the proportion of the best strain range fluctuated within the range of 82%-85%. With the increase of microporous diameter in x and y direction from 0.1 mm to 1.0 mm, the maximum equivalent stress increased from 32.4 MPa to 78.4 MPa, the maximum total deformation increased from 19.9 μm to 38.2 μm, and the proportion of the best strain range reduced from 90% to 53%. With the increase of microporous diameter in z direction, the maximum equivalent stress reduced from 58.8 MPa to 37.9 MPa, the maximum total deformation increased from 23.3 μm to 25.9 μm, and the proportion of the best strain range increased from 82% to 87%. Conclusions The greater the porosity and the proportion of the best strain range, the smaller maximum equivalent stress and maximum total deformation would be, the scaffolds would have the better biological and mechanical properties. These results have reference values for design and optimization of scaffold structure.