Luo Yan, Makkar Hardik, Hu Yuntao, Chen Keyu, Purohit Prashant K, Vining Kyle H
Mechanical Engineering and Applied Mechanics, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Preventive and Restorative Dentistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
ACS Mater Lett. 2025 Aug 11;7(9):3150-3158. doi: 10.1021/acsmaterialslett.5c00817. eCollection 2025 Sep 1.
Natural biopolymer hydrogels often suffer from relatively low moduli and an inability to maintain structure and mechanics under cyclic loading, limiting their utility in dynamic mechanical environments. Here, a cross-linked collagen cryogel scaffold was fabricated by precompression to densify the network. Following lyophilization, the porous scaffolds sustained >90% axial compressive strain with 200 cycles. Ogden hyperelastic modeling and second harmonic generation (SHG) imaging revealed fiber alignment, densification, and strain-stiffening contributing to resilience under repetitive large-scale loading. After rehydration, cross-linked and densified hydrogels showed network stability and recoverability under cyclic loading, with significantly reduced phase transition strains compared to non-cross-linked controls. The scaffolds supported cell encapsulation and maintained cell viability after 50 cycles of 90% strain. Cyclic loading significantly densified the encapsulated cells in the loading direction, comparable to nonloaded controls. Overall, these results suggest that densified, shape memory collagen scaffolds provide a mechanically robust and biocompatible system for dynamic environments.
天然生物聚合物水凝胶通常模量相对较低，且在循环加载下无法维持结构和力学性能，这限制了它们在动态力学环境中的应用。在此，通过预压缩制备了一种交联胶原蛋白冷冻凝胶支架，以致密化网络。冻干后，多孔支架在200次循环中承受了>90%的轴向压缩应变。奥格登超弹性模型和二次谐波产生（SHG）成像显示，纤维排列、致密化和应变强化有助于在重复大规模加载下的弹性恢复。再水化后，交联和致密化的水凝胶在循环加载下显示出网络稳定性和可恢复性，与未交联的对照相比，相变应变显著降低。支架支持细胞封装，并在90%应变的50次循环后维持细胞活力。循环加载使封装细胞在加载方向上显著致密化，与未加载的对照相当。总体而言，这些结果表明，致密化的形状记忆胶原蛋白支架为动态环境提供了一种机械坚固且生物相容的系统。
