title: Inductively heated shape memory polymer for the magnetic actuation of medical devices.
abstract: Presently, there is interest in making medical devices such as expandable stents and intravascular microactuators from shape memory polymer (SMP). One of the key challenges in realizing SMP medical devices is the implementation of a safe and effective method of thermally actuating various device geometries in vivo. A novel scheme of actuation by Curie-thermoregulated inductive heating is presented. Prototype medical devices made from SMP loaded with nickel zinc ferrite ferromagnetic particles were actuated in air by applying an alternating magnetic field to induce heating. Dynamic mechanical thermal analysis was performed on both the particle-loaded and neat SMP materials to assess the impact of the ferrite particles on the mechanical properties of the samples. Calorimetry was used to quantify the rate of heat generation as a function of particle size and volumetric loading of ferrite particles in the SMP. These tests demonstrated the feasibility of SMP actuation by inductive heating. Rapid and uniform heating was achieved in complex device geometries and particle loading up to 10% volume content did not interfere with the shape recovery of the SMP.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. buckley@alum.mit.edu
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Buckley
authors.forename: Gareth H
authors.initials: GH
authors.lastname: McKinley
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Wilson
authors.forename: Ward
authors.initials: W
authors.lastname: Small
authors.forename: William J
authors.initials: WJ
authors.lastname: Benett
authors.forename: Jane P
authors.initials: JP
authors.lastname: Bearinger
authors.forename: Michael W
authors.initials: MW
authors.lastname: McElfresh
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Maitland
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry* / Q000528:radiation effects*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D004864:Equipment and Supplies; D006358:Hot Temperature; D008280:Magnetics / Q000295:instrumentation*; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D001672:Biocompatible Materials; D011108:Polymers