Bicontinuous aqueous two-phase systems based on GelMA and dextran for tailored porous hydrogels in 3D Tissue Engineering

基于 GelMA 和葡聚糖的双连续水性两相系统，用于 3D 组织工程中定制的多孔水凝胶

• 批准号: 516822371
• 负责人: Professor Dr.-Ing. Horst Fischer
• 金额: --
• 依托单位: Lehrstuhl für Physikalische Chemie II
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/516822371?language=en
• 关键词: Bicontinuous; aqueous; two; phase; systems

In 3D tissue engineering, cells are embedded in cytocompatible hydrogels and processed by casting or bioprinting. Within the 3D structure, the post-processing cellular behavior is determined mainly by the hydrogels' microstructure. Conventional hydrogels are often limited in their tunability, in particular regarding their pore size and structure, and thus encapsulated cells are restricted in proliferation, spreading, migration, and differentiation. To address these shortcomings, we synthesize and investigate novel hydrogel blends based on an aqueous two-phase system (ATPS) consisting of gelatin methacryloyl (GelMA) and dextran. In proof-of-principle experiments, we synthesized homogeneous, regular disconnected-porous and bicontinuous interconnected-porous gels by finely tuning the phase separation mechanism and kinetics of the ATPS solution before ultraviolet (UV) light crosslinking of the GelMA phase and washing out the dextran phase. We showed in preliminary experiments that the hydrogels' pore characteristics were stable after printing. The bicontinuous ATPS hydrogel was suitable for growing several exemplary phenotypically different cell types: Human mesenchymal stem cells, periodontal ligament fibroblasts, and human neuroblastoma cancer cells all maintained optimal viability and expected morphology after seven days of cultivation. Thus, there is a great motivation and necessity to understand the underlying physico-chemical principles that determine the phase separation and structure formation processes in aqueous mixtures of polyampholytes and neutral polysaccharides finally leading to hydrogels with controlled microstructure. In addition, we will examine the effect of the 3D printing process, in particular the printing-induced shear stress on phase separation, the final hydrogel microstructure and their mechanical properties. The affinity of different cell types to grow in ATPS hydrogels will be investigated by evaluating their behavior in both cast and printed hydrogels with bicontinuous microstructure. Furthermore, we want to understand the partitioning of chemoattractants within ATPS solutions and gels. Finally, cell-laden ATPS solutions will be investigated concerning their phase separation mechanisms and the cellular response to both, (bio)printing and post-printing UV-crosslinking will be studied. The insights gained upon these investigations will allow understanding the dominating (macro)molecular interactions and enable the design of extracellular matrix-simulating 3D structures with high-level biomimicry holding the potential to open new opportunities and applications for tissue engineering and regenerative medicine.

在3D组织工程中，细胞嵌入细胞相容性水凝胶中，并通过铸造或生物打印来处理。在3D结构中，后处理的细胞行为主要由水凝胶的微结构确定。常规水凝胶通常受到其可调性的限制，尤其是其孔径和结构，因此封装的细胞受到增殖，扩散，迁移和分化的限制。为了解决这些缺点，我们根据由明胶甲基丙烯酰基（Gelma）和右旋烷组成的水性两相（ATP）合成并研究新型水凝胶混合物。在原则实验证明中，我们通过对紫外线（UV）在凝胶相交联的光之前，将ATPS溶液的相位分离机制和动力学合成均匀的，常规的断开孔和双连接互连 - 孔凝胶，并在凝胶相互交联之前并清洗脱氧剂阶段。我们在初步实验中表明，印刷后水凝胶的孔特性是稳定的。双连续的ATP水凝胶适用于种植几种示例性表型不同的细胞类型：人间质干细胞，牙周韧带成纤维细胞和人类神经细胞癌细胞均保持最佳生存能力，并且预期培养了7天后的形态。因此，有一个很大的动力和必要性，可以理解基本的物理化学原理，这些原理决定了多增压剂和中性多糖水性混合物中的相分离和结构形成过程，最终导致具有受控微观结构的水凝胶。此外，我们将研究3D打印过程的效果，特别是印刷引起的剪切应力对相位分离，最终水凝胶微结构及其机械性能。不同细胞类型在ATP水凝胶中生长的亲和力将通过评估其在铸造和印刷水凝胶中具有双连续微结构的行为。此外，我们想了解ATPS溶液和凝胶中的趋化剂的分配。最后，将研究载有细胞的ATPS溶液，以了解其相分离机制以及对两者的细胞反应，（BIO）印刷和后印刷UV-Crosslinking。对这些研究获得的见解将允许理解主导（宏）分子相互作用，并能够设计出具有高级仿生的细胞外基质拟合3D结构，该结构有可能为组织工程和再生药物开放新的机会和应用。