A shape-memory hydrogel is a programmable hydrogel material that can store specific shapes and execute functions in response to stimuli. In this report, we developed shape-memory hydrogels by creating double-network polymeric structures using a physically cross-linking elastin-like polypeptide (ELP) and a chemically cross-linking polyacrylamide (PAM). We synthesized the hydrogel matrix by polymerizing the acrylamide mixed in an ELP solution. We exploited the lower critical solution temperature transition of the ELP to enable the hydrogel to hold a new desired shape at an elevated temperature of 55 °C. The original shape of the hydrogel can then be recovered by lowering the temperature to 20 °C. The shape-memory hydrogels we developed exhibit ultrafast functionality and high repeatability. Taking advantage of the temperature-induced shape-memory capability, we also demonstrate practical functions such as gripping an object and connecting two tubes. Our materials with effective temperature-driven shape-memory functionality will be useful for developing novel materials for biomedical applications in the future.

中文翻译：

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基于弹性蛋白的热响应形状记忆水凝胶。

形状记忆水凝胶是可编程的水凝胶材料，可以存储特定形状并响应刺激执行功能。在本报告中，我们通过使用物理交联的弹性蛋白样多肽（ELP）和化学交联的聚丙烯酰胺（PAM）创建双网络聚合物结构，开发了形状记忆水凝胶。我们通过聚合混合在ELP溶液中的丙烯酰胺合成了水凝胶基质。我们利用了ELP的较低临界溶液温度转变，以使水凝胶能够在55°C的高温下保持新的所需形状。然后可以通过将温度降低至20°C恢复水凝胶的原始形状。我们开发的形状记忆水凝胶具有超快的功能性和高重复性。利用温度感应的形状记忆功能，我们还演示了一些实用功能，例如抓紧物体并连接两个管。我们的材料具有有效的温度驱动形状记忆功能，将在将来为生物医学应用开发新型材料时有用。