Materials Science

4D Printed Biocompatible Magnetic Composite for Minimally Invasive Deployable Structures

Authors

Abstract

4D printing of shape memory polymers (SMPs) and composites has been realized for a multitude of applications spanning healthcare, soft robotics, environment, space, etc. However, demonstrating such materials for in vivo applications has not been possible to a large extent due to the unavailability of suitable materials with recovery temperatures around physiological levels. Also, direct heating to trigger shape recovery in SMPs is not a practical and elegant approach in many cases. In this study, polylactide-co-trimethylene carbonate (PLMC), an SMP, has been endowed with magnetic iron oxide (Fe3O4) nanoparticles to realize remote heating under alternating magnetic field and at temperatures around 40°C. The PLMC-5% Fe3O4 composite was 3D printed into a variety of shapes, including scaffolds, fixed into pre-programmed temporary shapes to be deployed minimally invasively, and then recovered into original shapes under magnetic actuation. The shape recovery was excellent (>99%) and fast (under 20-30 s). Additionally, these magnetic composites could potentially be guided to the site of deployment through permanent magnets. Both PLMC and its composites were printed in distinct regions of a single structure, deformed, and then recovered by selective and sequential stimulation of magnetic field and heat, respectively. The materials (both PLMC and its nanocomposite) exhibited favorable in vitro and in vivo biocompatibility, thus highlighting their usefulness for being used as deployable tissue scaffolds and medical devices, among other implantable applications.

Content

Thumbnail image of Choudhury manuscript - main file.pdf

Supplementary material

Thumbnail image of Choudhury manuscript - SI file.pdf
SI text file
Provides additional data on materials characterization and in vivo biocompatibility results
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Video 1
V1: Shape recovery of a deformed 2D star under alternating magnetic field (4X)
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Video 2
V2: Shape recovery of a deformed 2D butterfly under alternating magnetic field (4X)
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Video 3
V3: Shape recovery of a deformed 2D fish under alternating magnetic field (4X)
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Video 4
V4: Shape recovery of a deformed 3D petal under an alternating magnetic field
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Video 5
V5: Shape recovery of a deformed 3D butterfly under an alternating magnetic field
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Video 6
V6: Shape recovery of a deformed 3D fish under an alternating magnetic field
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Video 7
V7: Shape recovery of a deformed 3D porous scaffold under an alternating magnetic field
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Video 8
V8: Restrictive shape recovery of deformed shape placed inside a tube under an alternating magnetic field
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Video 9
V9: Magnetic guidance of deformed shape inside a glass tube with bar magnets
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Video 10
V10: Partial shape recovery of a dual-printed star under an alternating magnetic field
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Video 11
V11: Partial shape recovery of a dual-printed cross under an alternating magnetic field
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Video 12
V12: Partial shape recovery of a dual-printed butterfly under an alternating magnetic field
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Video 13
V13: Partial shape recovery of a dual-printed petal under an alternating magnetic field