Muscle-like Hydrogels by Mechanical Training

In our recent work, We propose a strategy of mechanical training to achieve the aligned nanofibrillar architectures of skeletal muscles in synthetic hydrogels, resulting in the combinational muscle-like properties for the first time.

Abstract:
Skeletal muscles possess the combinational properties of high fatigue resistances (1000 J/m2), high strengths (1 MPa), low Young’s moduli (100 kPa), and high water contents (70 − 80 wt%), which have not been achieved in synthetic hydrogels. The muscle-like properties are highly desirable for hydrogels’ nascent applications in load-bearing artificial tissues and soft devices. In this paper, we propose a strategy of mechanical training to achieve the aligned nanofibrillar architectures of skeletal muscles in synthetic hydrogels, resulting in the combinational muscle-like properties for the first time. These properties are obtained through the training-induced alignment of nanofibrils, without additional chemical modifications or additives. In situ confocal microscopy of the hydrogels' fracturing processes reveals that the fatigue resistance results from the crack pinning by the aligned nanofibrils, which require much higher energy to fracture than the amorphous polymer chains. This strategy is particularly applicable for three-dimensionally printed microstructures of hydrogels, in which we can achieve isotropically fatigue-resistant, strong yet compliant properties.

Shaoting Lin#, Ji Liu#, Xinyue Liu, Xuanhe Zhao*, Muscle-like Fatigue-resistant Hydrogels by Mechanical Training, Proceedings of the National Academy of Sciences of the United States of America, doi.org/10.1073/pnas.1903019116, 2019