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，细胞被嵌入细胞相容性水凝胶中，并通过铸造或生物打印进行处理。在3D结构中，后处理细胞行为主要由水凝胶的微观结构决定。传统的水凝胶通常在可调性方面受到限制，特别是在其孔径和结构方面，因此包裹的细胞在增殖、扩散、迁移和分化方面受到限制。为了解决这些缺点，我们合成和研究新的水凝胶共混物的基础上的水两相系统（ATPS）由明胶甲基丙烯酰（GelMA）和葡聚糖。在原理验证实验中，我们通过微调在GelMA相的紫外（UV）光交联和洗出葡聚糖相之前ATPS溶液的相分离机制和动力学，合成了均匀的、规则的不连通多孔和双连续的互连多孔凝胶。我们在初步实验中表明，水凝胶的孔特性在印刷后是稳定的。双连续ATPS水凝胶适合于生长几种示例性的表型不同的细胞类型：人间充质干细胞、牙周韧带成纤维细胞和人神经母细胞瘤癌细胞在培养七天后都保持最佳的活力和预期的形态。因此，有很大的动机和必要性来了解决定聚两性电解质和中性多糖水性混合物中相分离和结构形成过程的基本物理化学原理，最终导致具有受控微观结构的水凝胶。此外，我们将研究3D打印过程的影响，特别是打印诱导的剪切应力对相分离，最终水凝胶微观结构及其机械性能的影响。不同细胞类型在ATPS水凝胶中生长的亲和力将通过评估它们在具有双连续微结构的浇铸和印刷水凝胶中的行为来研究。此外，我们想了解ATPS溶液和凝胶内的化学引诱物的分配。最后，将研究载有细胞的ATPS溶液的相分离机制，并研究细胞对（生物）打印和打印后UV交联的反应。在这些研究中获得的见解将使我们能够理解主要的（宏观）分子相互作用，并能够设计具有高水平仿生学的细胞外基质模拟3D结构，从而为组织工程和再生医学开辟新的机会和应用。