4D Printed Shape Morphing Biocompatible Materials Based on Anisotropic Ferromagnetic Nanoparticles

Abstract

Shape morphing materials, especially those fabricated by 4D printing, are gaining much attention due to their versatility of actuation and capability of being programmed in advance. These materials become particularly interesting for biomedical applications where implant materials could be remotely actuated, exerting a force on the surrounding tissues and cells. However, applications in this field have been restricted due to the biocompatibility of the materials and the character of the required stimuli, generally not compatible with physiological environments. Magnetic nanoparticles (MNPs) represent a great opportunity to this end; however, the actuation results in a uniform movement toward the magnet that requires anchoring of the object. Here, for the first time, the application of anisotropic Fe3O4 MNPs is described, and synthesized by a novel and easy route, that can be aligned on pre‐defined patterns within objects printed by digital light processing, resulting in materials that can be actuated remotely (4D printing). These nanoparticles (178 nm × 55 nm), show good biocompatibility when directly seeded on top of human mesenchymal stem cells, despite being uptaken. Most importantly, the alignment of the MNPs can tune the movement of fabricated nanocomposite materials, resulting in complex movements of attraction or repulsion depending on the direction of the applied magnetic field.

3D-printed liquid metal polymer composites as NIR-responsive 4D printing soft robot

“…Nanoparticles with unique properties (such as photosensitivity and chemosensitivity) can enhance the stimuli-responsiveness of printed objects, thereby enabling precise and efficient shape changes. For instance, Kuhnt et al successfully integrated magnetic iron oxide nanoparticles into 3D-printed objects, thereby producing composites that demonstrated thermally and remotely controlled shape-memory behavior under an alternating magnetic field 15 . An alternative approach to producing composites capable of inducing shape transformation involved the incorporation of conductive carbon black particles or carbon nanotubes into 3D-printed polymers, thus sensitizing the composites to electrothermal stimulation.…”

Smart implants: 4D-printed shape-morphing scaffolds for medical implantation

“…Adding MNPs into the printing ink is one of the methods to fabricate 4D constructs that can be actuated by external magnetic fields. Magnetite ferroferric oxide (Fe 3 O 4 ) microparticles are the most commonly used [ 39 , 62 - 64 ] . In this way, contactless control of product deformation under a magnetic field can be realized.…”

Magnetic Shape-Memory Heuslers Turn to Bio: Cytocompatibility of Ni–Mn–Ga Films and Biomedical Perspective

“…Successful tissue regeneration in biomedicine is a complex bioprocess which in many cases benefits from mechanical boosts that mimic an essential physiological environment. Direct magnetic field mechanical stimulation of cells by magnetic materials is among the prominent approaches but the main challenge is to develop a mechanism to control and customize magnetic response of the materials over time. , At the other end of the spectrum, magneto-mechanical approaches have recently shown new strategies for cancer therapy through a specific physical perturbation inside the microenvironment of the tumor cells. Also, in this case, control and customization of the magnetic response are crucial. , MSM Heuslers have superior advantage; they provide a complex platform with multiple magnetic field response mechanisms that can be customized to be governed by MSM effect, , phase transformation, − magnetic field-induced torque, − or combinations of all.…”

“…Direct magnetic field mechanical stimulation of cells by magnetic materials is among the prominent approaches but the main challenge is to develop a mechanism to control and customize magnetic response of the materials over time. 15,16 At the other end of the spectrum, magneto-mechanical approaches have recently shown new strategies for cancer therapy through a specific physical perturbation inside the microenvironment of the tumor cells. Also, in this case, control and customization of the magnetic response are crucial.…”