Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
Radboud University Medical Centre, Radboud Institute for Molecular Life Sciences, Department of Tumor Immunology, Geert Grooteplein 26-28, 6500 HB, Nijmegen, The Netherlands.
Nat Commun. 2019 Feb 5;10(1):609. doi: 10.1038/s41467-019-08569-4.
Although common in biology, controlled stiffening of hydrogels in vitro is difficult to achieve; the required stimuli are commonly large and/or the stiffening amplitudes small. Here, we describe the hierarchical mechanics of ultra-responsive hybrid hydrogels composed of two synthetic networks, one semi-flexible and stress-responsive, the other flexible and thermoresponsive. Heating collapses the flexible network, which generates internal stress that causes the hybrid gel to stiffen up to 50 times its original modulus; an effect that is instantaneous and fully reversible. The average generated forces amount to ~1 pN per network fibre, which are similar to values found for stiffening resulting from myosin molecular motors in actin. The excellent control, reversible nature and large response gives access to many biological and bio-like applications, including tissue engineering with truly dynamic mechanics and life-like matter.
尽管在生物学中很常见，但体外控制水凝胶的刚度是很困难的；所需的刺激通常很大，且/或刚度幅度很小。在这里，我们描述了由两个合成网络组成的超响应混合水凝胶的分级力学特性，一个是半柔性和应激响应的，另一个是灵活和温敏的。加热会破坏柔性网络，从而产生内部应力，使混合凝胶的硬度增加到其原始模量的 50 倍；这种效果是瞬间的且完全可逆的。平均产生的力约为每根纤维 1 pN，与肌球蛋白分子马达在肌动蛋白中引起的硬度增加相当。这种出色的控制、可逆性和大响应使许多生物学和类生物学应用成为可能，包括具有真正动态力学和类生命物质的组织工程。
