摘要：Osteoarthritis (OA), identified as one of the priorities for the Bone and Joint Decade, is one of the most prevalent joint diseases, which causes pain and disability of joints in the adult population. Secondary OA usually stems from repetitive overloading to the osteochondral (OC) unit, which could result in cartilage damage and changes in the subchondral bone, leading to mechanical instability of the joint and loss of joint function. Tissue engineering approaches have emerged for the repair of cartilage defects and damages to the subchondral bone in the early stages of OA and have shown potential in restoring the joint's function. In this approach, the use of three-dimensional scaffolds (with or without cells) provides support for tissue growth. Commercially available OC scaffolds have been studied in OA patients for repair and regeneration of OC defects. However, none of these scaffolds has shown satisfactory clinical results. This article reviews the OC tissue structure and the design, manufacturing and performance of current OC scaffolds in treatment of OA. The findings demonstrate the importance of biological and biomechanical fixations of OC scaffolds to the host tissue in achieving an improved cartilage fill and a hyaline-like tissue formation. Achieving a strong and stable subchondral bone support that helps the regeneration of overlying cartilage seems to be still a grand challenge for the early treatment of OA.

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：Tissue-engineered cartilage(TEC)remains a potential alternative for the repair of articular cartilage ***,there has been a significant different between the properties of TEC and those of natural *** have shown that mechanical stimulation such as compressive load can help regulate matrix remodelling in TEC,thus affecting its biomechanical ***,the influences of shear induced from the tissue fluid phase have not been well studied and may play an important role in tissue regeneration especially when integrated with the compressive ***,the aim of this study was to quantitatively investigate the effects of combined loading mechanisms on TEC in vitro.A bespoke biosimulator was built to incorporate the coupled motion of compression,friction and *** specimens,encapsulating freshly isolated rabbit chondrocytes in a hydrogel,were cultured within the biosimulator under various mechanical stimulations for 4 weeks,and the tissue activity,matrix contents and the mechanical properties were *** groups were categorized according to different mechanical stimulation combinations,including strain(5-20%at 5%intervals)and frequency(0.25 Hz,0.5 Hz,1 Hz),and the effects on tissue behaviour were *** the dynamic culture process,a combined load was applied to simulate the combined effects of compression,friction and shear on articular cartilage during human *** results indicated that a larger strain and higher frequency were more favourable for the specimen in terms of the cell proliferation and extracellular matrix ***,the combined mechanical stimulation was more beneficial to matrix remodelling than the single loading ***,the contribution of the combined mechanical stimulation to the engineered cartilaginous tissue matrix was not sufficient to impede biodegradation of the tissue with culture time.

摘要：Polycaprolactone-carboxymethyl cellulose composites have been obtained and used to print porous structures by material *** materials used contained 0,2 and 5% w/w of the carboxymethyl cellulose *** structures have been analyzed in terms of their morphology (including the evaluation of their porosity),mechanical properties under compression load and cell *** affinity has been evaluated by culturing sheep mesenchymal stem cells and analyzing their viability by the Alamar Blue(R)assay at days 1,3,6 and *** results show that composites samples have similar values of porosity and apparent density than pure polycaprolactone ***,samples containing 5%w/w of carboxymethyl cellulose have micropores on the filaments due to a hindered deposition *** characteristic affects the mechanical properties of the structures,so these ones have a mean compression modulus significantly lower than pure polycaprolactone ***, the samples containing 2%w/w of carboxymethyl cellulose show no significant difference with the pure polycaprolactone ones in terms of their mechanical ***,the presence of 2%w/w of additive improves cell proliferation on the surface of the porous *** complementary information,the flow properties of the composite materials were studied and the power law equations at 210℃ obtained,as this temperature was the 3D printing *** equations can be useful for simulation and designing purposes of other manufacturing processes.

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。