Application of additive manufacturing technologies for the realization of clinically relevant cocultures of mammalian cells and microalgae

通过细胞移植（通常与作为人工基质的生物材料组合）使丧失的组织功能再生是用于治疗各种疾病和组织缺损的有前景的方法。然而，基于细胞的疗法的成功在很大程度上取决于细胞的供应，特别是在植入后立即提供氧气。对于大多数组织工程方法，快速血运重建的策略是研究的主题。另一方面，存在旨在避免植入细胞与血液中的免疫组分接触以避免排斥的治疗方法，因此需要用于有效供氧的替代策略。高度临床相关性的一个实例是在患有1型糖尿病的患者的情况下移植同种异体（潜在异种）胰岛。第一个短期实验证明了利用光合活性微藻覆盖胰岛高需氧量的巨大潜力。在拟议的项目中，将通过生物打印实现光合活性微藻和哺乳动物细胞的共培养。两种细胞类型将被封装（彼此分离）在水凝胶中;通过应用3D绘图的增材制造技术进行成形，将使用不同细胞类型在具有限定几何形状的结构化水凝胶基质中的空间限定排列的优点。除此之外，还将开发具有光耦合和集成氧传感器的生物反应器系统，该系统允许根据实际氧浓度对光合作用活性进行需求导向控制。与共培养/生物反应器系统的基本原理将开发为不同的细胞类型之间的相互作用，对细胞的氧浓度的影响，以及不同的隔间之间的氧运输的系统调查。此外，哺乳动物细胞与光合作用产生的氧气的有效和持久的供应应实现作为翻译的共培养/生物反应器系统向胰岛移植的临床应用的先决条件。为了建立共培养物，应当鉴定能够在37°C下生长并且以高光合速率为特征的合适的微藻菌株。将制定出满足两种细胞类型需求的共培养条件。有机碳源对光自养微藻的影响以及光对异养哺乳动物细胞的影响将被详细研究。最后，预计有关微藻生物打印的项目结果将为生物技术应用提供有价值的见解。

The regeneration of lost tissue functions by transplantation of cells, often in combination with biomaterials as artificial matrix, is a promising approach for the treatment of various diseases and tissue defects. However, the success of cell-based therapies strongly depends on the supply of the cells, especially with oxygen, immediately after implantation. For most tissue engineering approaches, strategies for a fast revascularization are subject of research. On the other side, there are treatment approaches which intend to circumvent contact of the implanted cells with immunological components in blood in order to avoid rejection and therefore need alternative strategies for efficient oxygen supply. One example of high clinical relevance is the transplantation of allogenic (potentially xenogenic) pancreatic islets of Langerhans in case of patients suffering from diabetes type 1. First short-term experiments demonstrated the great potential of the utilization of photosynthetically active microalgae for coverage of the high oxygen demand of pancreatic islets.In the proposed project, cocultures of photosynthetically active microalgae and mammalian cells will be realized by means of bioprinting. Both cell types will be encapsulated (separated from each other) in hydrogels; by applying the additive manufacturing technology of 3D plotting for shaping, the advantages of a spatially defined arrangement of the different cell types in a structured hydrogel matrix with defined geometry will be used. Beyond that, a bioreactor system with light coupling and integrated oxygen sensors will be developed that allows a demand-oriented control of the photosynthesis activity depending on the actual oxygen concentration. With the coculture/bioreactor system the fundamentals will be developed for a systematic investigation of the interaction between the different cell types, the influence of the oxygen concentration on the cells as well as the oxygen transport between the different compartments. Moreover, an efficient and long-lasting supply of the mammalian cells with photosynthetically generated oxygen should be achieved as prerequisite for the translation of the coculture/bioreactor system towards clinical application for islet transplantation. For the establishment of the coculture, a suitable microalgae strain should be identified which is able to growth at 37°C and is characterized by a high rate of photosynthesis. Coculture conditions will be worked out which meet the demands of both cell types. The influence of organic carbon sources on the photoautotrophic microalgae as well as the influence of light on the heterotrophic mammalian cells will be investigated in detail. Finally, it is expected that results of the project concerning the bioprinting with microalgae will provide valuable insights for biotechnological applications.