Australian Institute for Innovative Materials, University of Wollongong, Wollongong, NSW 2522, Australia.
School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, NSW 2006, Australia.
Sci Robot. 2021 Apr 28;6(53). doi: 10.1126/scirobotics.abf4788.
Powering miniature robots using actuating materials that mimic skeletal muscle is attractive because conventional mechanical drive systems cannot be readily downsized. However, muscle is not the only mechanically active system in nature, and the thousandfold contraction of eukaryotic DNA into the cell nucleus suggests an alternative mechanism for high-stroke artificial muscles. Our analysis reveals that the compaction of DNA generates a mass-normalized mechanical work output exceeding that of skeletal muscle, and this result inspired the development of composite double-helix fibers that reversibly convert twist to DNA-like plectonemic or solenoidal supercoils by simple swelling and deswelling. Our modeling-optimized twisted fibers give contraction strokes as high as 90% with a maximum gravimetric work 36 times higher than skeletal muscle. We found that our supercoiling coiled fibers simultaneously provide high stroke and high work capacity, which is rare in other artificial muscles.
利用模仿骨骼肌的致动材料为微型机器人提供动力很有吸引力，因为传统的机械驱动系统无法轻易缩小尺寸。然而，肌肉并不是自然界中唯一具有机械活性的系统，真核生物 DNA 千倍压缩到细胞核中，这为高冲程人工肌肉提供了另一种替代机制。我们的分析表明，DNA 的压缩产生了归一化质量机械功输出，超过了骨骼肌，这一结果启发了复合双螺旋纤维的开发，这种纤维通过简单的膨胀和收缩可逆地将扭转转换为类似于 DNA 的螺旋或螺线管超螺旋。我们经过建模优化的扭曲纤维的收缩冲程高达 90%，最大重量工作比骨骼肌高 36 倍。我们发现，我们的超螺旋卷曲纤维同时提供了高冲程和高工作能力，这在其他人工肌肉中很少见。
