Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Spain.
Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain.
ACS Appl Bio Mater. 2023 Sep 18;6(9):3638-3647. doi: 10.1021/acsabm.3c00126. Epub 2023 Sep 5.
There is a growing interest in developing natural hydrogel-based scaffolds to culture cells in a three-dimensional (3D) millieu that better mimics the cells' microenvironment. A promising approach is to use hydrogels from animal tissues, such as decellularized extracellular matrices; however, they usually exhibit suboptimal mechanical properties compared to native tissue and their composition with hundreds of different protein complicates to elucidate which stimulus triggers cell's responses. As simpler scaffolds, type I collagen hydrogels are used to study cell behavior in mechanobiology even though they are also softer than native tissues. In this work, type I collagen is mixed with bacterial nanocellulose fibers (BCf) to develop reinforced scaffolds with mechanical properties suitable for 3D cell culture. BCf were produced from blended pellicles biosynthesized from . Then, BCf were mixed with concentrated collagen from rat-tail tendons to form composite hydrogels. Confocal laser scanning microscopy and scanning electron microscopy images confirmed the homogeneous macro- and microdistribution of both natural polymers. Porosity analysis confirmed that BCf do not disrupt the scaffold structure. Tensile strength and rheology measurements demonstrated the reinforcement action of BCf (43% increased stiffness) compared to the collagen hydrogel while maintaining the same viscoelastic response. Additionally, this reinforcement of collagen hydrogels with BCf offers the possibility to mix cells before gelation and then proceed to the culture of the 3D cell scaffolds. We obtained scaffolds with human bone marrow-derived mesenchymal stromal cells or human fibroblasts within the composite hydrogels, allowing a homogeneous 3D viable culture for at least 7 days. A smaller surface shrinkage in the reinforced hydrogels compared to type I collagen hydrogels confirmed the strengthening of the composite hydrogels. These collagen hydrogels reinforced with BCf might emerge as a promising platform for 3D organ modeling, tissue-engineering applications, and suitable to conduct fundamental mechanobiology studies.
人们越来越感兴趣的是开发基于天然水凝胶的支架，以在更能模拟细胞微环境的三维（3D）环境中培养细胞。一种很有前途的方法是使用来自动物组织的水凝胶，如去细胞细胞外基质；然而，与天然组织相比，它们通常表现出不理想的机械性能，并且其组成中含有数百种不同的蛋白质，这使得阐明哪种刺激会引发细胞反应变得复杂。作为更简单的支架，I 型胶原水凝胶被用于研究细胞在机械生物学中的行为，尽管它们也比天然组织柔软。在这项工作中，I 型胶原与细菌纳米纤维素纤维（BCf）混合，以开发具有适合 3D 细胞培养的机械性能的增强型支架。BCf 是由混合从. 生物合成的菌膜制成的，然后将 BCf 与来自大鼠尾巴肌腱的浓缩胶原混合形成复合水凝胶。共焦激光扫描显微镜和扫描电子显微镜图像证实了两种天然聚合物的均匀宏观和微观分布。孔隙率分析证实，BCf 不会破坏支架结构。拉伸强度和流变学测量表明，与胶原水凝胶相比，BCf 具有增强作用（刚度增加 43%），同时保持相同的粘弹性响应。此外，这种用 BCf 增强胶原水凝胶为在凝胶化之前混合细胞并随后进行 3D 细胞支架培养提供了可能性。我们在复合水凝胶中获得了人骨髓间充质基质细胞或人成纤维细胞的支架，允许至少 7 天进行均匀的 3D 活细胞培养。与 I 型胶原水凝胶相比，增强水凝胶的表面收缩较小，这证实了复合水凝胶的增强。这些用 BCf 增强的胶原水凝胶可能成为 3D 器官建模、组织工程应用的有前途的平台，并且适合进行基础机械生物学研究。
