Kim Byoung Soo, Lee Jung-Seob, Gao Ge, Cho Dong-Woo
Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea.
Biofabrication. 2017 Jun 6;9(2):025034. doi: 10.1088/1758-5090/aa71c8.
Three-dimensional (3D) cell-printing has been emerging as a promising technology with which to build up human skin models by enabling rapid and versatile design. Despite the technological advances, challenges remain in the development of fully functional models that recapitulate complexities in the native tissue. Moreover, although several approaches have been explored for the development of biomimetic human skin models, the present skin models based on multistep fabrication methods using polydimethylsiloxane chips and commercial transwell inserts could be tackled by leveraging 3D cell-printing technology. In this paper, we present a new 3D cell-printing strategy for engineering a 3D human skin model with a functional transwell system in a single-step process. A hybrid 3D cell-printing system was developed, allowing for the use of extrusion and inkjet modules at the same time. We began by revealing the significance of each module in engineering human skin models; by using the extrusion-dispensing module, we engineered a collagen-based construct with polycaprolactone (PCL) mesh that prevented the contraction of collagen during tissue maturation; the inkjet-based dispensing module was used to uniformly distribute keratinocytes. Taking these features together, we engineered a human skin model with a functional transwell system; the transwell system and fibroblast-populated dermis were consecutively fabricated by using the extrusion modules. Following this process, keratinocytes were uniformly distributed onto the engineered dermis by the inkjet module. Our transwell system indicates a supportive 3D construct composed of PCL, enabling the maturation of a skin model without the aid of commercial transwell inserts. This skin model revealed favorable biological characteristics that included a stabilized fibroblast-stretched dermis and stratified epidermis layers after 14 days. It was also observed that a 50 times reduction in cost was achieved and 10 times less medium was used than in a conventional culture. Collectively, because this single-step process opens up chances for versatile designs, we envision that our cell-printing strategy could provide an attractive platform in engineering various human skin models.
三维（3D）细胞打印作为一种有前景的技术正在兴起，它能够通过实现快速且多样的设计来构建人体皮肤模型。尽管技术取得了进步，但在开发能够重现天然组织复杂性的全功能模型方面仍存在挑战。此外，虽然已经探索了多种开发仿生人体皮肤模型的方法，但目前基于使用聚二甲基硅氧烷芯片和商用Transwell小室的多步制造方法的皮肤模型，可以通过利用3D细胞打印技术来解决。在本文中，我们提出了一种新的3D细胞打印策略，用于在一步过程中构建具有功能性Transwell系统的3D人体皮肤模型。开发了一种混合3D细胞打印系统，允许同时使用挤出和喷墨模块。我们首先揭示了每个模块在构建人体皮肤模型中的重要性；通过使用挤出分配模块，我们构建了一种基于胶原蛋白的结构，其中包含聚己内酯（PCL）网格，可防止胶原蛋白在组织成熟过程中收缩；基于喷墨的分配模块用于均匀分布角质形成细胞。综合这些特点，我们构建了一个具有功能性Transwell系统的人体皮肤模型；通过使用挤出模块依次构建了Transwell系统和成纤维细胞填充的真皮。在此过程之后，通过喷墨模块将角质形成细胞均匀分布在构建好的真皮上。我们的Transwell系统是一种由PCL组成的支持性3D结构，无需商用Transwell小室就能使皮肤模型成熟。这种皮肤模型显示出良好的生物学特性，包括14天后稳定的成纤维细胞拉伸真皮和分层的表皮层。还观察到，与传统培养相比，成本降低了50倍，培养基用量减少了10倍。总的来说，由于这种一步法为多样的设计提供了机会，我们设想我们的细胞打印策略可以为构建各种人体皮肤模型提供一个有吸引力的平台。
