Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1.
Physik Department E22, Technische Universität München, James-Franck-Strasse, Garching 85748, Germany.
Nat Commun. 2013;4:2974. doi: 10.1038/ncomms3974.
Protein-based hydrogels usually do not exhibit high stretchability or toughness, significantly limiting the scope of their potential biomedical applications. Here we report the engineering of a chemically cross-linked, highly elastic and tough protein hydrogel using a mechanically extremely labile, de novo-designed protein that assumes the classical ferredoxin-like fold structure. Due to the low mechanical stability of the ferredoxin-like fold structure, swelling of hydrogels causes a significant fraction of the folded domains to unfold. Subsequent collapse and aggregation of unfolded ferredoxin-like domains leads to intertwining of physically and chemically cross-linked networks, entailing hydrogels with unusual physical and mechanical properties: a negative swelling ratio, high stretchability and toughness. These hydrogels can withstand an average strain of 450% before breaking and show massive energy dissipation. Upon relaxation, refolding of the ferredoxin-like domains enables the hydrogel to recover its massive hysteresis. This novel biomaterial may expand the scope of hydrogel applications in tissue engineering.
基于蛋白质的水凝胶通常不具有高拉伸性或韧性，这大大限制了它们在潜在生物医学应用中的范围。在这里，我们报告了一种使用机械上极不稳定的、新设计的蛋白质来工程化学交联的、高弹性和坚韧的蛋白质水凝胶，这种蛋白质具有经典的铁氧还蛋白样折叠结构。由于铁氧还蛋白样折叠结构的机械稳定性低，水凝胶的溶胀会导致折叠结构域的很大一部分展开。随后展开的铁氧还蛋白样结构域的崩溃和聚集导致物理和化学交联网络的交织，使水凝胶具有异常的物理和机械性能：负溶胀比、高拉伸性和韧性。这些水凝胶在断裂前可以承受 450%的平均应变，并表现出大量的能量耗散。在松弛时，铁氧还蛋白样结构域的重新折叠使水凝胶能够恢复其大量的滞后。这种新型生物材料可能会扩大水凝胶在组织工程中的应用范围。
