Biocompatible Film‐Coating of Magnetic Soft Robots for Mucoadhesive Locomotion

Abstract

Magnetically‐actuated soft robots for medical applications are required to be functional, biocompatible, as well as capable of robust motion inside human organs. In this paper, a ring‐shaped magnetic soft robot, with a flexible biopolymeric film coating, capable of motion on mucus‐coated surfaces is designed and investigated. The biopolymeric film made from chitosan–glycerol (C–G) solution endows the robot with robust locomotion capabilities on surfaces of diverse geometrical shapes and orientations. By utilizing mucoadhesive locomotion, the robot has the potential to carry out clinical procedures on enclosed mucus‐coated tissue surfaces. Material characterization shows that the mucoadhesion increases with the increase of contact times and/or preload forces. The softness of the C–G film can be adjusted by controlling the concentration of glycerol. The ring‐shaped design and magnetization profile decouple the locomotion and functions of the robot. Additionally, the C–G film‐coated robot is tested to be biocompatible for a human colorectal adenocarcinoma cell line with epithelial morphology (HT29). The C–G film reduces the negative effects (superoxide generation) of ferromagnetic particles. Three robot functions including pick‐and‐place, cargo transportation, and liquid capsule release are demonstrated on different surfaces to show the maneuverability, functionality, and potential of implementing clinical procedures through mucoadhesion.

Minimally designed thermo-magnetic dual responsive soft robots for complex applications

“…Such a coating could also potentially enhance the robot's biocompatibility and prevent leakage of magnetic particles. 55 …”

Intestinal retentive systems – recent advances and emerging approaches

“…The ring features a chitosan-glycerol film to enhance mucoadhesion and other capabilities including localized cargo deployment and liquid capsule release. The chitosan-glycerol film played a vital role in inducing strong mucoadhesion between the soft robot and the mucosa, with a normal adhesion force of up to 20 mN observed for a mucus concentration of 5% and a contact time of 10 s. 72 Lee et al developed a magnetically actuated capsule with the ability to hold multiple mucoadhesive patches prepared with mussel-inspired catechol-conjugated chitosan for targeted drug delivery in cancer treatment. The capsule featured a neodymium magnet for movement within the gut using an externally applied magnetic field, along with an actuation system that allowed for the active release of patches at specific sections.…”

A magnetic multi-layer soft robot for on-demand targeted adhesion

“…By designing an actuation method and optimizing energy bursting, the jumping motion of magnetic soft robots has also been achieved in unstructured aquatic-terrestrial environments 17 . Moreover, locomotion can be realized in unstructured three-dimensional environments by considering surface microstructures and surface coating of the robots, such as microspikes 18 , 19 and mucoadhesive film 20 loaded by magnetic soft robots.…”