Max Planck Institute for Colloids and Interfaces, Potsdam, Germany; Julius Wolff Institute, Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Berlin, Germany.
Julius Wolff Institute, Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Berlin, Germany.
Biomater Adv. 2023 Aug;151:213423. doi: 10.1016/j.bioadv.2023.213423. Epub 2023 Apr 25.
In nature, tissues are patterned, but most biomaterials used in human applications are not. Patterned biomaterials offer the opportunity to mimic spatially segregating biophysical and biochemical properties found in nature. Engineering such properties allows to study cell-matrix interactions in anisotropic matrices in great detail. Here, we developed alginate-based hydrogels with patterns in stiffness and degradation, composed of distinct areas of soft non-degradable (Soft-NoDeg) and stiff degradable (Stiff-Deg) material properties. The hydrogels exhibit emerging patterns in stiffness and degradability over time, taking advantage of dual crosslinking: Diels-Alder covalent crosslinking (norbornene-tetrazine, non degradable) and UV-mediated peptide crosslinking (matrix metalloprotease sensitive peptide, enzymatically degradable). The materials were mechanically characterized using rheology for single-phase and surface micro-indentation for patterned materials. 3D encapsulated mouse embryonic fibroblasts (MEFs) allowed to characterize the anisotropic cell-matrix interaction in terms of cell morphology by employing a novel image-based quantification tool. Live/dead staining showed no differences in cell viability but distinct patterns in proliferation, with higher cell number in Stiff-Deg materials at day 14. Patterns of projected cell area became visible already at day 1, with larger values in Soft-NoDeg materials. This was inverted at day 14, when larger projected cell areas were identified in Stiff-Deg. This shift was accompanied by a significant decrease in cell circularity in Stiff-Deg. The control of anisotropic cell morphology by the material patterns was also confirmed by a significant increase in filopodia number and length in Stiff-Deg materials. The novel image-based quantification tool was useful to spatially visualize and quantify the anisotropic cell response in 3D hydrogels with stiffness-degradation spatial patterns. Our results show that patterning of stiffness and degradability allows to control cell anisotropic response in 3D and can be quantified by image-based strategies. This allows a deeper understanding of cell-matrix interactions in a multicomponent material.
在自然界中，组织是有图案的，但大多数用于人类应用的生物材料却没有。图案化的生物材料提供了模仿自然界中空间分离的生物物理和生化特性的机会。工程化这些特性可以使我们在各向异性基质中详细研究细胞-基质相互作用。在这里，我们开发了具有刚度和降解图案的基于海藻酸盐的水凝胶，这些水凝胶由软不可降解（Soft-NoDeg）和硬可降解（Stiff-Deg）材料特性的不同区域组成。水凝胶在时间上表现出刚度和降解性的新兴图案，利用双重交联：Diels-Alder 共价交联（降冰片烯-四嗪，不可降解）和 UV 介导的肽交联（基质金属蛋白酶敏感肽，可酶降解）。使用流变学对单相和图案材料的表面微压痕对材料进行机械特性表征。3D 封装的小鼠胚胎成纤维细胞（MEFs）通过采用一种新的基于图像的定量工具，用于表征细胞形态的各向异性细胞-基质相互作用。活/死染色显示细胞活力没有差异，但增殖模式不同，在第 14 天，Stiff-Deg 材料中的细胞数量更高。在第 1 天已经可以看到细胞投影面积的模式，Soft-NoDeg 材料中的值更大。在第 14 天，Stiff-Deg 中的值更大时，这种情况发生了逆转。这种转变伴随着 Stiff-Deg 中细胞圆形度的显著降低。Stiff-Deg 材料中丝状伪足数量和长度的显著增加也证实了材料图案对各向异性细胞形态的控制。新的基于图像的定量工具可用于空间可视化和量化具有刚度-降解空间图案的 3D 水凝胶中的各向异性细胞反应。我们的结果表明，刚度和降解性的图案化允许控制 3D 中的细胞各向异性反应，并可通过基于图像的策略进行量化。这可以更深入地了解多组分材料中的细胞-基质相互作用。
