November 13, 2019
How an elastic filament deforms beneath stress has been quantified in simulations, with implications for the design of synthetic muscle tissue.
N. Charles et al., Phys. Rev. Lett. (2019)
Future generations of robots and prosthetic gadgets would require compact synthetic muscle tissue which can be highly effective and environment friendly. One method to make such muscle tissue is to twist elastic fibers in order that they coil up and shorten in response to a stimulus akin to temperature, mimicking the contraction of the actual factor. Now, Lakshminarayanan Mahadevan at Harvard College and colleagues have quantified this course of by simulating how smooth elastic filaments reply when they’re strongly stretched and twisted.
Elastic filaments accommodate twisting forces by contorting themselves into a variety of configurations. Although the variety of attainable preparations may seem infinite, for a filament that’s anchored at every finish—like a muscle—the shapes are literally made up of a mixture of three primary kinds: The filament stays straight, or it kinds a easy corkscrew-like coil referred to as a solenoid, or it turns into a DNA-like loop of intertwined helices referred to as a plectoneme.
Of their simulations, the researchers modeled totally different drive regimes to provide you with a part diagram that relates a filament’s remaining configuration to the forces utilized to it throughout twisting. The workforce confirmed that, beneath sturdy stress (attributable to stretching when it’s anchored) and weak twisting, the filament tends to stay straight. Robust twisting with out a lot stress yields plectonemes, and when the filament is strongly stretched and twisted, it adopts a solenoidal type. Close to the triple boundary the place the part areas of the three shapes meet, the filament displays a fancy mixture of all three.
The researchers hope that their outcomes will result in higher designed synthetic muscle tissue. Their insights may also be related in understanding how polymers can deform when twisted and the way magnetic area strains get their topology and geometry.
This analysis is revealed in Bodily Overview Letters.
Marric Stephens is a contract science author based mostly in Bristol, UK.