Esophagus‐Inspired Actuator for Solid Transportation via the Synergy of Lubrication and Contractile Deformation

Abstract

Directional transportation of objects has important applications from energy transfer and intelligent robots to biomedical devices. Although breakthroughs in liquid migration on 2D surfaces or 3D tubular devices have been achieved, realizing smooth/on‐demand transportation of constrained solids within a 3D cavity environment under harsh pressurized environment still remains a daunting challenge, where strong interface friction force becomes the main obstacle restricting the movement of solids. Inspired by typical feeding mechanism in natural esophagus system which synergistically couples a lubricating mucosa surface with the peristaltic contraction deformation of the cavity, herein, this challenge is addressed by constructing an esophagus‐inspired layered tubular actuator with a slippery inner surface and responsive hydrogel matrix to realize spherical solid propulsion by photo(thermo)‐induced cavity deformation. The as‐constructed tubular actuator containing Fe3O4 nanoparticles exhibits local volumetric shrinkage upon NIR‐irradiation, which can generate large hydrodynamic pressure and considerable mechanical extrusion force (Fdriving force ≈ 0.18 N) to overcome low interface friction force (ffriction force ≈ 0.03 N), enabling on‐demand transportation of constrained (pressure: 0.103 MPa) spherical solids over a long distance in an arbitrary direction. This actuator is anticipated to be used as bionic medicine transportation devices or artificial in vitro esophagus simulation systems, for example, to help formula eating‐related physiotherapy plans for patients and astronauts.

Visible-Light-Mediated Nano-biomineralization of Customizable Tough Hydrogels for Biomimetic Tissue Engineering

“…This change would be desirable in applications such as joint repair because reduced friction would enhance the lubrication performance at interfaces (Figure S23). ,, …”

“…This change would be desirable in applications such as joint repair because reduced friction would enhance the lubrication performance at interfaces (Figure S23). 20,50,51 The feasibility of producing BTHs with customizable designs was evaluated because clinical applications will require various 2D or 3D structures. The rheological characterization was used to monitor the gelation of BTH specimens in response to light irradiation.…”

Recent progress of bioinspired cartilage hydrogel lubrication materials

“…The biomacromolecules tethered to the cartilage surface can form a polymer brush border, which plays a pivotal role in friction reduction. In order to mimic that unique polymer brush structure, Zhou's group proposed an effective method called sSI-ATRP (subsurface initiated atom transfer radical polymerisation) to graft hydrophilic polymer brushes onto the surface of hydrogels [143][144][145][146][147]. In 2020, Rong et al used the sSI-ATRP method to form a layer of thick hydrophilic polyelectrolyte brushes into the subsurface of a stiff hydrogel (Figure 9a) [148].…”

Preparation and characterization of temperature‐responsive Ca–alginate/poly(N‐isopropylacrylamide) hydrogel

“…42 These actuators can be used as bionic medicine transportation devices or artificial in vitro esophagus simulation systems. 43 However, it becomes a major challenge to produce and control the dimensions of tubular hydrogels using robust and convenient methods. Moreover, the intelligent/easy manipulation of the diameter shrinkage and peristaltic motion behaviors needs to be addressed urgently.…”