title: Elasticity and viscoelasticity of embolization microspheres.
abstract: The present study investigates the mechanical properties of three embolization microspheres (E-ms): tris-acryl gelatin microspheres (TG-ms), acrylamido polyvinyl alcohol microspheres (APVA-ms), and polyphosphazene-coated polymethylmethacrylate microspheres (PP-PMMA-ms). Compression and relaxation tests were performed on monolayers of particles and their Young's moduli and relaxation half times (RHTs) were determined. The elasticity of E-ms was evaluated by applying Hertz theory with the assumptions of incompressibility and a Poisson's ratio of 0.5. The Young's moduli of TG-ms, APVA-ms, and PP-PMMA-ms were 39.6±5.05 kPa, 18.8±4.00 kPa, and 13.6±1.98 kPa, respectively. The RHTs of TG-ms, APVA-ms, and PP-PMMA-ms were 52.3±5.56 s, 59.1±8.16 s, and 31.0±7.01 s, respectively. TG-ms have a high rigidity and deform slightly under a sustained compression since they have a high elasticity. PP-PMMA-ms are soft and deform a lot under sustained compression. They are more viscous than the other two microspheres. APVA-ms have intermediate material properties, having the same low rigidity as PP-PMMA-ms and being more elastic than TG-ms.
authors.affiliation: Division of Radiology, Department of Medical Technology, Osaka University Hospital, and Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama Toyonaka, Osaka 560-8531, Japan. hidaka@hp-rad.med.osaka-u.ac.jp
authors.forename: Kuniyuki
authors.initials: K
authors.lastname: Hidaka
authors.forename: Laurence
authors.initials: L
authors.lastname: Moine
authors.forename: Guillaume
authors.initials: G
authors.lastname: Collin
authors.forename: Denis
authors.initials: D
authors.lastname: Labarre
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Grossiord
authors.forename: Nicolas
authors.initials: N
authors.lastname: Huang
authors.forename: Keigo
authors.initials: K
authors.lastname: Osuga
authors.forename: Shigeo
authors.initials: S
authors.lastname: Wada
authors.forename: Alexandre
authors.initials: A
authors.lastname: Laurent
mesh_terms: D001158:Arteries / Q000378:metabolism; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism; D055119:Elastic Modulus; D004621:Embolization, Therapeutic / Q000379:methods*; D005780:Gelatin / Q000737:chemistry; D008863:Microspheres; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011142:Polyvinyl Alcohol / Q000737:chemistry; D013314:Stress, Mechanical; D014783:Viscosity
chemical_list: D001672:Biocompatible Materials; D005780:Gelatin; D011142:Polyvinyl Alcohol; D019904:Polymethyl Methacrylate