Dual high-stroke and high–work capacity artificial muscles inspired by DNA supercoiling

Abstract

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.

A Shift from Efficiency to Adaptability: Recent Progress in Biomimetic Interactive Soft Robotics in Wet Environments

“…HA <87 [ 84,92] 10 −2 [ 83] -10 2 [ 93] 10 −3 -0.1 [94] 10 −5 [ 95] -35 [96] -<1 [97] Light, heat, pH, water, etc. TCY 0.2-90 [98][99][100][101][102][103] 2.5 × 10 3 [ 104] -1.6 × 10 4 [ 105] 2.4 × 10 3 [ 91] 1.3 × 10 3 [ 105]− 5 × 10 3 [ 104] 15 [98] -50 [ 103] 2-12 [ 79,99,100,106] Heat, solvent Reproduced with permission. [132] Copyright 2021, Springer Nature.…”

Programmable DNA Hydrogels as Artificial Extracellular Matrix

“…As a natural polymer, DNA has received increasing attention for constructing hydrogels. [ 36–38 ] Compared to other natural polymer based hydrogels, DNA hydrogels have unique programmable addressability based on the Watson‐Crick base pairing, [ 39,40 ] which brings precisely customized structures, [ 41 ] tunable mechanical properties, [ 42 ] easy functionalization, [ 43 ] conditional responsiveness, [ 44,45 ] and practical architectural construction. [ 46 ] In 1996, DNA molecules as crosslinked units were first introduced into synthetic polymer systems to generate hybrid hydrogels.…”

“…To engineer the dynamic environment of natural ECM, there remain challenges to modulate the physicochemical properties within the hydrogels.As a natural polymer, DNA has received increasing attention for constructing hydrogels. [36][37][38] Compared to other natural polymer based hydrogels, DNA hydrogels have unique programmable addressability based on the Watson-Crick base pairing, [39,40] which brings precisely customized structures, [41] The cell microenvironment plays a crucial role in regulating cell behavior and fate in physiological and pathological processes. As the fundamental component of the cell microenvironment, extracellular matrix (ECM) typically possesses complex ordered structures and provides essential physical and chemical cues to the cells.…”

Oscillating light engine realized by photothermal solvent evaporation

“…Actuators can generate bending, contraction, elongation, and rotation morphing motions upon exposure to external stimuli to output mechanical energy 9 – 12 . Different types of actuators have been successfully developed, including dielectric elastomer actuators 13 , 14 , conducting polymers 15 , 16 , shape memory polymers and alloys 17 , 18 , twisted fiber artificial muscles 19 , 20 , ionic polymer composites 21 , pneumatic actuators 22 , and other inorganic materials 23 , 24 . The major application area of thin film actuator is either actuation or morphing.…”