静电纺丝已广泛用于制造复杂的细胞外基质样微环境,以进行组织工程,因为它具有复制结构仿生微观和纳米形貌线索的能力。然而,这些纳米纤维结构通常局限于二维系统或局限于不能提供受控多尺度图案的三维系统。因此,在这项工作中使用了一种静电纺丝方式,以自动化方式制造具有高度可定制三维(3D)结构的载有软骨细胞的纳米纤维支架,最终目的是为关节软骨组织工程重建合适的3D支架。通过组合多个纳米纤维和载有软骨细胞的水凝胶层设计和制造三种不同的架构,并在压缩生物反应器系统中进行体外测试。结果表明,可以精确控制静电纺丝聚己内酯和明胶纳米纤维的放置和排列,生成具有独特宏观孔隙率的三种独特结构,吸水能力,和机械性能。以格子状方式组织的体系结构是高度多孔的,具有大量的孔互连性,导致高吸水能力,但较差的压缩模量和相对较弱的能量耗散能力。甜甜圈状的3D几何形状是最密集的,具有较低的肿胀,但最高的压缩模量和改善的能量耗散能力。第三种结构结合了格子和甜甜圈状的纤维排列,在孔隙率方面表现出中介行为,吸水,压缩模量,和能量耗散能力。甜甜圈状3D结构的特性证明了关节软骨组织工程的巨大潜力,当它模仿关键地形时,化学,和软骨细胞周围环境的力学特性。事实上,这些结构特征与动态压缩机械刺激相结合,在生存力和生物合成生产方面触发了最佳的体外结果。
Electrospinning has been widely employed to fabricate complex extracellular matrix-like microenvironments for tissue engineering due to its ability to replicate structurally biomimetic micro- and nanotopographic cues. Nevertheless, these nanofibrous structures are typically either confined to bidimensional systems or confined to three-dimensional ones that are unable to provide controlled multiscale patterns. Thus, an electrospinning modality was used in this work to fabricate chondrocyte-laden nanofibrous scaffolds with highly customizable three-dimensional (3D) architectures in an automated manner, with the ultimate goal of recreating a suitable 3D scaffold for articular cartilage tissue engineering. Three distinct architectures were designed and fabricated by combining multiple nanofibrous and chondrocyte-laden hydrogel layers and tested in vitro in a compression bioreactor system. Results demonstrated that it was possible to precisely control the placement and alignment of electrospun polycaprolactone and gelatin nanofibers, generating three unique architectures with distinctive macroscale porosity, water absorption capacity, and mechanical properties. The architecture organized in a lattice-like fashion was highly porous with substantial pore interconnectivity, resulting in a high-water absorption capacity but a poor compression modulus and relatively weaker energy dissipation capacity. The donut-like 3D geometry was the densest, with lower swelling, but the highest compression modulus and improved energy dissipation ability. The third architecture combined a lattice and donut-like fibrous arrangement, exhibiting intermediary behavior in terms of porosity, water absorption, compression modulus, and energy dissipation capacity. The properties of the donut-like 3D architecture demonstrated great potential for articular cartilage tissue engineering, as it mimicked key topographic, chemical, and mechanical characteristics of chondrocytes\' surrounding environment. In fact, the combination of these architectural features with a dynamically compressive mechanical stimulus triggered the best in vitro results in terms of viability and biosynthetic production.