Jones Christian F E, Di Cio Stefania, Connelly John T, Gautrot Julien E
Institute of Bioengineering, Queen Mary University of London, London, United Kingdom.
School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom.
Front Bioeng Biotechnol. 2022 Jul 19;10:915702. doi: 10.3389/fbioe.2022.915702. eCollection 2022.
Tissue-engineered skin constructs have been under development since the 1980s as a replacement for human skin tissues and animal models for therapeutics and cosmetic testing. These have evolved from simple single-cell assays to increasingly complex models with integrated dermal equivalents and multiple cell types including a dermis, epidermis, and vasculature. The development of micro-engineered platforms and biomaterials has enabled scientists to better recreate and capture the tissue microenvironment , including the vascularization of tissue models and their integration into microfluidic chips. However, to date, microvascularized human skin equivalents in a microfluidic context have not been reported. Here, we present the design of a novel skin-on-a-chip model integrating human-derived primary and immortalized cells in a full-thickness skin equivalent. The model is housed in a microfluidic device, in which a microvasculature was previously established. We characterize the impact of our chip design on the quality of the microvascular networks formed and evidence that this enables the formation of more homogenous networks. We developed a methodology to harvest tissues from embedded chips, after 14 days of culture, and characterize the impact of culture conditions and vascularization (including with pericyte co-cultures) on the stratification of the epidermis in the resulting skin equivalents. Our results indicate that vascularization enhances stratification and differentiation (thickness, architecture, and expression of terminal differentiation markers such as involucrin and transglutaminase 1), allowing the formation of more mature skin equivalents in microfluidic chips. The skin-on-a-chip tissue equivalents developed, because of their realistic microvasculature, may find applications for testing efficacy and safety of therapeutics delivered systemically, in a human context.
自20世纪80年代以来，组织工程皮肤构建物一直在研发中，作为人类皮肤组织的替代品以及用于治疗和化妆品测试的动物模型。这些构建物已从简单的单细胞检测发展到越来越复杂的模型，包括整合的真皮等效物和多种细胞类型，如真皮、表皮和脉管系统。微工程平台和生物材料的发展使科学家能够更好地重建和捕捉组织微环境，包括组织模型的血管化及其与微流控芯片的整合。然而，迄今为止，尚未有在微流控环境中实现微血管化的人类皮肤等效物的报道。在此，我们展示了一种新型芯片上皮肤模型的设计，该模型在全层皮肤等效物中整合了人源原代细胞和永生化细胞。该模型置于一个微流控装置中，其中先前已建立了微血管系统。我们表征了芯片设计对所形成微血管网络质量的影响，并证明这能够形成更均匀的网络。我们开发了一种方法，在培养14天后从嵌入式芯片中收获组织，并表征培养条件和血管化（包括与周细胞共培养）对所得皮肤等效物中表皮分层的影响。我们的结果表明，血管化增强了分层和分化（厚度、结构以及终末分化标志物如兜甲蛋白和转谷氨酰胺酶1的表达），从而在微流控芯片中形成更成熟的皮肤等效物。所开发的芯片上皮肤组织等效物由于其逼真的微血管系统，可能在人体环境中用于测试全身给药治疗药物的疗效和安全性。
