摘要：The repair of osteochondral defects is one of the major clinical challenges in ***-established osteochondral tissue engineering methods have shown promising results for the early treatment of small ***,less success has been achieved for the regeneration of large defects,which is mainly due to the mechanical environment of the joint and the heterogeneous nature of the *** this study,we developed a multi-layered osteochondral scaffold to match the heterogeneous nature of osteochondral tissue by harnessing additive manufacturing technologies and combining the established art laser sintering and material extrusion *** developed scaffold is based on a titanium and polylactic acid matrix-reinforced collagen“sandwich”composite *** microstructure and mechanical properties of the scaffold were examined,and its safety and efficacy in the repair of large osteochondral defects were tested in an ovine condyle *** 12-week in vivo evaluation period revealed extensive and significantly higher bone in-growth in the multi-layered scaffold compared with the collagen–hAp scaffold,and the achieved stable mechanical fixation provided strong support to the healing of the overlying cartilage,as demonstrated by hyaline-like cartilage *** histological examination showed that the regenerated cartilage in the multi-layer scaffold group was superior to that formed in the control *** genes such as aggrecan and collagen-II were upregulated in the scaffold and were higher than those in the control *** findings showed the safety and efficacy of the cell-free“translation-ready”osteochondral scaffold,which has the potential to be used in a one-step surgical procedure for the treatment of large osteochondral defects.

摘要：To get an optimal product of orthopaedic implant or regenerative medicine needs to follow trialand-error analyses to investigate suitable product’s material,structure,mechanical properites *** whole process from in vivo tests to clinical trials is expensive and *** model is seen as a useful analysis tool to make the product development.A series of models for simulating tissue engineering process from cell attachment to tissue regeneration are *** challenging is that models for simulating tissue engineering processes are developed *** cell to tissue regeneration,it would go through blood injection after moving out the defect;to cell disperse and attach on the scaffold;to proliferation,migration and differentiation;and to the final part-becoming mature *** paper reviewed models that related to tissue engineering process,aiming to provide an opportunity for researchers to develop a mature model for whole tissue engineering *** article focuses on the model analysis methods of cell adhesion,nutrient transport and cell proliferation,differentiation and migration in tissue *** cell adhesion model,one of the most accurate method is to use discrete phase model to govern cell movement and use Stanton-Rutland model for simulating cell *** for nutrient transport model,numerical model coupling with volume of fluid model and species transport model together is suitable for predicting nutrient transport *** cell proliferation,differentiation and migration,finite element method with random-walk algorithm is one the most advanced way to simulate these *** of the model analysis methods require further experiments to verify the accuracy and *** to the lack of technology to detect the rate of nutrient diffusion,there are especially few researches on model analysis methods in the area of blood ***,there is still a lot of work to be done in the resea

摘要：为提高骨缺损修复的治疗效果,设计孔隙率为78.8%、70.8%、62.6%和54.4%的梯度多孔钛支架(分别表示为P1,P2,P3和P4),并通过选择性激光熔化技术进行制备。通过模拟和实验方法研究支架的成形性、显微组织、力学性能和渗透性能。模拟结果表明,4种梯度结构的最大等效应力和渗透性分别在569.1~1469.0MPa和(21.7~54.6)×10^(−9)m^(2)范围内,并且P3和P4具有更小的最大等效应力,表明P3和P4具有更高的强度。P3和P4结构支架的显微组织为α'马氏体,屈服强度和弹性模量分别为185.3~250.8MPa和6.1~9.7GPa。相比于P3结构支架,P4结构支架展现出更高的强度和与皮质骨更加匹配的弹性模量,并且其渗透性(18.6×10^(−9)m^(2))在人体骨组织渗透性范围内。因此,具有P4结构支架有望被应用于骨科植入领域。