Three-dimensional Printing of Multilayered Tissue Engineering Scaffolds.

The field of tissue engineering has produced new therapies for the repair of damaged tissues and organs, utilizing biomimetic scaffolds that mirror the mechanical and biological properties of host tissue. The emergence of three-dimensional printing (3DP) technologies has enabled the fabrication of highly complex scaffolds which offer a more accurate replication of native tissue properties and architecture than previously possible. Of strong interest to tissue engineers is the construction of multilayered scaffolds that target distinct regions of complex tissues. Musculoskeletal and dental tissues in particular, such as the osteochondral unit and periodontal complex, are composed of multiple interfacing tissue types, and thus benefit from the usage of multilayered scaffold fabrication. Traditional 3DP technologies such as extrusion printing and selective laser sintering have been used for the construction of scaffolds with gradient architectures and mixed material compositions. Additionally, emerging bioprinting strategies have been used for the direct printing and spatial patterning of cells and chemical factors, capturing the complex organization found in the body. To better replicate the varied and gradated properties of larger tissues, researchers have created scaffolds composed of multiple materials spanning natural polymers, synthetic polymers, and ceramics. By utilizing high precision 3DP techniques and judicious material selection, scaffolds can thus be designed to address the regeneration of previously challenging musculoskeletal, dental, and other heterogeneous target tissues. These multilayered 3DP strategies show great promise in the future of tissue engineering.

组织工程领域已经为受损组织和器官的修复开发出了新的疗法，它利用仿生支架来模拟宿主组织的力学和生物学特性。三维打印（3DP）技术的出现使得制造高度复杂的支架成为可能，这些支架比以往更精确地复制了天然组织的特性和结构。组织工程师们非常感兴趣的是构建针对复杂组织不同区域的多层支架。特别是肌肉骨骼和牙齿组织，比如骨软骨单元和牙周复合体，由多种相互连接的组织类型组成，因此受益于多层支架制造技术的应用。传统的3DP技术，如挤出打印和选择性激光烧结，已被用于构建具有梯度结构和混合材料成分的支架。此外，新兴的生物打印策略已被用于细胞和化学因子的直接打印和空间图案化，以捕捉体内发现的复杂组织结构。为了更好地复制较大组织的多样和渐变特性，研究人员已经制造出由多种材料组成的支架，这些材料涵盖天然聚合物、合成聚合物和陶瓷。通过利用高精度3DP技术和明智的材料选择，支架可以被设计用于解决以前具有挑战性的肌肉骨骼、牙齿和其他异质性目标组织的再生问题。这些多层3DP策略在组织工程的未来展现出巨大的潜力。