title: Fabrication and in vitro degradation of porous fumarate-based polymer/alumoxane nanocomposite scaffolds for bone tissue engineering.
abstract: In this work, the fabrication and in vitro degradation of porous fumarate-based/alumoxane nanocomposites were evaluated for their potential as bone tissue engineering scaffolds. The biodegradable polymer poly (propylene fumarate)/propylene fumarate-diacrylate (PPF/PF-DA), a macrocomposite composed of PPF/PF-DA and boehmite microparticles, and a nanocomposite composed of PPF/PF-DA and surface-modified alumoxane nanoparticles were used to fabricate porous scaffolds by photo-crosslinking and salt-leaching. Scaffolds then underwent 12 weeks of in vitro degradation in phosphate buffered saline at 37 degrees C. The presence of boehmite microparticles and alumoxane nanoparticles in the polymer inhibited scaffold shrinkage during crosslinking. Furthermore, the incorporation of alumoxane nanoparticles into the polymer limited salt-leaching, perhaps due to tighter crosslinking within the nanocomposite. Analysis of crosslinking revealed that the acrylate and overall double bond conversions in the nanocomposite were higher than in the PPF/PF-DA polymer alone, though these differences were not significant. During 12 weeks of in vitro degradation, the nanocomposite lost 5.3% +/- 2.4% of its mass but maintained its compressive mechanical properties and porous architecture. The addition of alumoxane nanoparticles into the fumarate-based polymer did not significantly affect the degradation of the nanocomposite compared with the other materials in terms of mass loss, compressive properties, and porous structure. These results demonstrate the feasibility of fabricating degradable nanocomposite scaffolds for bone tissue engineering by photo-crosslinking and salt-leaching mixtures of fumarate-based polymers, alumoxane nanoparticles, and salt microparticles.
authors.affiliation: Department of Bioengineering, Rice University, P.O. Box 1892, MS 142, Houston, Texas 77251-1892, USA.
authors.forename: Amit S
authors.initials: AS
authors.lastname: Mistry
authors.forename: Stacy H
authors.initials: SH
authors.lastname: Cheng
authors.forename: Tiffany
authors.initials: T
authors.lastname: Yeh
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Christenson
authors.forename: John A
authors.initials: JA
authors.lastname: Jansen
authors.forename: Antonios G
authors.initials: AG
authors.lastname: Mikos
mesh_terms: D000536:Aluminum Hydroxide / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism; D001842:Bone and Bones / Q000502:physiology*; D019245:Compressive Strength; D005650:Fumarates / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008422:Materials Testing; D015394:Molecular Structure; D053761:Nanocomposites; D011108:Polymers / Q000737:chemistry / Q000378:metabolism; D011126:Polypropylenes / Q000737:chemistry / Q000378:metabolism; D016062:Porosity; D013314:Stress, Mechanical; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D005650:Fumarates; D011108:Polymers; D011126:Polypropylenes; C097850:poly(propylene fumarate); D000536:Aluminum Hydroxide; C069471:aluminum oxide hydroxide; D000537:Aluminum Oxide