Osteochondral tissue engineering (OCTE) involves the simulation of highly complex tissues with disparate biomechanical properties. OCTE is regarded as the best option for treating osteochondral defects, most of the drawbacks of current treatment methodologies can be addressed by this method. In recent years, the conventional scaffolds used in cartilage and bone regeneration are gradually being replaced by 3D printed scaffolds (3DP). In the present study, we devised the strategy of 3D printing for fabricating biphasic and integrated scaffolds that are loaded with bioactive factors for enhancing the osteochondral tissue regeneration. Polycaprolactone (PCL) and poly(lactic-co-glycolic acid) (PLGA), is used along with bioactive factors (chondroitin sulphate and beta-tricalcium phosphate (βTCP)) for the upper cartilage and lower bone layer respectively. The 3D printed bi-layered scaffolds with varying infill density, to mimic the native tissue, are not previously explored for OCTE. Hence, we tested the simultaneous osteochondrogenic differentiation inducing potential of the aforesaid 3D printed biphasic scaffolds in vitro, using rabbit adipose derived mesenchymal stem cells (ADMSCs). Further, the biphasic scaffolds were highly cytocompatible, with excellent cell adhesion properties and cellular morphology. Most importantly, these biphasic scaffolds directed the simultaneous differentiation of a single stem cell population in to two cell lineages (simultaneous differentiation of rabbit ADMSCs into chondrocytes and osteoblasts). Further, these scaffolds enhanced the production of ECM and induced robust expression of marker genes that is specific for respective cartilage and bone layers. The 3D printed OCTE scaffold of our study hence can simulate the native osteochondral unit and could be potential futuristic biomimetic scaffold for osteochondral defects. Further in vivo studies are warranted.

骨软骨组织工程 (OCTE) 涉及模拟具有不同生物力学特性的高度复杂的组织。OCTE 被认为是治疗骨软骨缺损的最佳选择，目前治疗方法的大部分缺点都可以通过这种方法解决。近年来，用于软骨和骨再生的常规支架正逐渐被3D打印支架（3DP）所取代。在本研究中，我们设计了 3D 打印策略来制造双相和集成支架，这些支架装载有生物活性因子，以增强骨软骨组织再生。聚己内酯 (PCL) 和聚乳酸-乙醇酸共聚物 (PLGA) 与生物活性因子（硫酸软骨素和 β-磷酸三钙 (βTCP)）一起分别用于上软骨和下骨层。具有不同填充密度的 3D 打印双层支架以模拟天然组织，以前没有针对 OCTE 进行过探索。因此，我们测试了上述 3D 打印双相支架的同时诱导骨软骨分化的潜力在体外，使用兔脂肪来源的间充质干细胞 (ADMSCs)。此外，双相支架具有高度的细胞相容性，具有优异的细胞粘附特性和细胞形态。最重要的是，这些双相支架指导单个干细胞群同时分化为两个细胞谱系（兔 ADMSCs 同时分化为软骨细胞和成骨细胞）。此外，这些支架增强了 ECM 的产生并诱导了对各自的软骨和骨层特异的标记基因的强烈表达。因此，我们研究的 3D 打印 OCTE 支架可以模拟原生骨软骨单元，并可能成为未来骨软骨缺损的仿生支架。有必要进行进一步的体内研究。