Medical Research Institute, Pusan National University, Yangsan, 626841, Republic of Korea.
Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
Adv Healthc Mater. 2023 Oct;12(27):e2301015. doi: 10.1002/adhm.202301015. Epub 2023 Aug 3.
To reconstruct an ideal full-thickness skin model, basal keratinocytes must be distributed as a confluent monolayer on the dermis. However, the currently available extrusion bioprinting method for the skin is limited when producing an air-exposed cellular monolayer because the cells are encapsulated within a bioink. This is the first study to use sacrificial gelatin-assisted extrusion bioprinting to reproduce a uniform and stratified epidermal layer. Experimental analyses of the rheological properties, printability, cell viability, and initial keratinocyte adhesion shows that the optimal gelatin bioink concentration is 4 wt.%. The appropriate thickness of the bioprinted gelatin structure for achieving a confluent keratinocyte layer is determined to be 400 µm. The suggested strategy generates a uniform keratinocyte monolayer with tight junctions throughout the central and peripheral regions, whereas manual seeding generates non-uniform cellular aggregates and vacancies. These results influence gene expression, exhibiting a propensity for epidermal differentiation. Finally, the gelatin-assisted keratinocytes are bioprinted onto a dermis composed of gelatin methacryloyl and dermis-derived decellularized extracellular matrix to establish a full-thickness skin model. Thus, this strategy leads to significant improvements in epidermal differentiation/stratification. The findings demonstrate that the gelatin-assisted approach is advantageous for recreating reliable full-thickness skin models with significant consistency for mass production.
为了重建理想的全厚皮肤模型，基底层角质形成细胞必须在真皮上分布为连续的单层。然而，目前用于皮肤的可挤出生物打印方法在生产暴露于空气的细胞单层时受到限制，因为细胞被封装在生物墨水中。这是首次使用牺牲明胶辅助挤出生物打印来重现均匀分层的表皮层的研究。对流变特性、可打印性、细胞活力和初始角质形成细胞黏附的实验分析表明，明胶生物墨水的最佳浓度为 4wt%。确定实现连续角质形成细胞层的最佳生物打印明胶结构厚度为 400µm。所提出的策略生成了具有紧密连接的均匀角质形成细胞单层，贯穿中央和周边区域，而手动播种则会产生不均匀的细胞聚集和空位。这些结果影响基因表达，表现出表皮分化的倾向。最后，将明胶辅助的角质形成细胞生物打印到由明胶甲基丙烯酰和真皮脱细胞化细胞外基质组成的真皮上，以建立全厚皮肤模型。因此，该策略可显著改善表皮分化/分层。这些发现表明，明胶辅助方法有利于重建具有显著一致性的可靠全厚皮肤模型，可用于大规模生产。
