Elasticity and viscoelasticity of embolization microspheres
Kuniyuki Hidaka1, Laurence Moine, Guillaume Collin
1Division 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
Journal of the Mechanical Behavior of Biomedical Materials
|November 22, 2011
Summary
This study compared the mechanical properties of three embolization microspheres (E-ms). Tris-acryl gelatin microspheres (TG-ms) are rigid, while polyphosphazene-coated polymethylmethacrylate microspheres (PP-PMMA-ms) are soft and viscous.
Area of Science:
- Biomaterials Science
- Mechanical Engineering
- Medical Device Development
Background:
- Embolization microspheres (E-ms) are critical in minimally invasive procedures.
- Understanding the mechanical properties of E-ms is essential for predicting their behavior in vivo.
- Previous research has focused on biocompatibility, but mechanical characterization requires further investigation.
Purpose of the Study:
- To investigate and compare the mechanical properties of three distinct types of embolization microspheres.
- To determine the Young's modulus and relaxation half-time (RHT) for each microsphere type.
- To correlate mechanical properties with observed deformation and viscoelastic behavior.
Main Methods:
- Compression and relaxation tests were performed on monolayers of tris-acryl gelatin microspheres (TG-ms), acrylamido polyvinyl alcohol microspheres (APVA-ms), and polyphosphazene-coated polymethylmethacrylate microspheres (PP-PMMA-ms).
- Hertz theory was applied to evaluate elasticity, assuming incompressibility and a Poisson's ratio of 0.5.
- Young's moduli and RHTs were calculated for each microsphere type.
Main Results:
- Young's moduli: TG-ms (39.6±5.05 kPa), APVA-ms (18.8±4.00 kPa), PP-PMMA-ms (13.6±1.98 kPa).
- RHTs: TG-ms (52.3±5.56 s), APVA-ms (59.1±8.16 s), PP-PMMA-ms (31.0±7.01 s).
- TG-ms exhibited high rigidity and low deformation; PP-PMMA-ms were soft, highly deformable, and viscous; APVA-ms showed intermediate properties.
Conclusions:
- Microsphere material composition significantly influences mechanical properties like rigidity and viscoelasticity.
- TG-ms are suitable for applications requiring minimal deformation, while PP-PMMA-ms may be preferred for their viscoelasticity.
- APVA-ms offer a balance of elasticity and rigidity, providing versatile options for embolization therapies.
