Bioinspired high-power-density strong contractile hydrogel by programmable elastic recoil

Abstract

Stimuli-responsive hydrogels have large deformability but—when applied as actuators, smart switch, and artificial muscles—suffer from low work density due to low deliverable forces (~2 kPa) and speed through the osmotic pressure–driven actuation. Inspired by the energy conversion mechanism of many creatures during jumping, we designed an elastic-driven strong contractile hydrogel through storing and releasing elastic potential energy in polymer network. It can generate high contractile force (40 kPa) rapidly at ultrahigh work density (15.3 kJ/m3), outperforming current hydrogels (~0.01 kJ/m3) and even biological muscles (~8 kJ/m3). This demonstrated elastic energy storing and releasing method endows hydrogels with elasticity-plasticity switchability, multi-stable deformability in fully reversible and programmable manners, and anisotropic or isotropic deformation. With the high power density and programmability via this customizable modular design, these hydrogels demonstrated potential for broad applications in artificial muscles, contractile wound dressing, and high-power actuators.

Current hydrogel advances in physicochemical and biological response-driven biomedical application diversity

“…Apart from the above-mentioned application practices, hydrogels could be also extended to other biomedical fields, such as tissue fillers, 393 bioimaging, 394 biosensor, 395 conductive wearable/implantable biodevices, 66 , 67 soft robots, 396 etc. Hydrogel products used for cosmetic filler have been widely reported and evaluated, where HA gel is the mostly used.…”

Engineering Tough Metallosupramolecular Hydrogel Films with Kirigami Structures for Compliant Soft Electronics

“…In the engineering field, hydrogel films also These tough hydrogels are not stale at redox conditions that transform Fe 3+ ions to Fe 2+ ions having poor capacity to form robust coordination bonds with carboxyl groups. [37,38] To address these issues, it is highly desired to seek another kind of metal-coordination complexes that are robust, colorless, and compatible with the radical polymerization, i.e., stable in pregel solution and little influence on polymerization.…”

Stimuli-Responsive Toughening of Hydrogels

“…Very recently, it has been reported that photo-sensitive coordinate bonds can efficiently release the energy stored by the hydrogel. 128 The authors took poly(acrylamide-co-acrylic acid) (P(AAm-co-AAc)) hydrogel for illustration. After being prestretched and immersed in Fe 3+ solution, the deformation of hydrogel is fixed by the coordinate bonds between Fe 3+ and carboxyl groups from AAc units which temporarily store potential energy in hydrogels.…”

“…After UV irradiation, Fe 3+ is reduced to Fe 2+ , resulting in the breakdown of the coordinate bonds and the fast release of the elastic potential energy stored in the hydrogel. 128 This strategy of storing and releasing elastic energy, based on the destabilization of the coordination bonds by photoreduction, endows hydrogels with an elasticity-plasticity switchability, multi-stable deformability in fully reversible and programmable manners, and anisotropic or isotropic deformations. With the high power density and programmability via this customizable modular design, these hydrogels demonstrated potential for broad applications in artificial muscles, contractile wound dressing, and high-power actuators.…”