title: Synthesis, characterization of calcium phosphates/polyurethane composites for weight-bearing implants.
abstract: Calcium phosphate (CaP)/polymer composites have been studied as an alternative graft material for the treatment of bone defects. In this study, lysine-triisocyanate-based polyurethane (PUR) composites were synthesized from both hydroxyapatite (HA) and β-tricalcium phosphate (TCP) to reduce the brittleness of CaP and increase the bioactivity of the polymer. The mechanical properties and in vitro cellular response were investigated for both HA/PUR and TCP/PUR composites. The composites were implanted in femoral defects in rats, and in vivo bioactivity was evaluated by X-rays, micro-computed tomography (μCT), and histological sections. In biomechanical testing, PUR improved the mechanical properties of the CaP, thus rendering it potentially suitable for weight-bearing applications. In vitro cell culture studies showed that CaP/PUR composites are biocompatible, with β-TCP enhancing the cell viability and proliferation relative to HA. CaP/PUR composites also supported the differentiation of osteoblastic cells on the materials. When implanted in rat femoral defects, the CaP/PUR composites were biocompatible and osteoconductive with no adverse inflammatory response, as evidenced by X-rays, μCT images, and histological sections. Additionally, a histological examination showed evidence of cellular infiltration and appositional remodeling. These results suggest that CaP/PUR composites could be potentially useful biomaterials for weight-bearing orthopaedic implants.
authors.affiliation: Department of Orthopaedics and Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee 37232-8774, USA.
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Yoshii
authors.forename: Jerald E
authors.initials: JE
authors.lastname: Dumas
authors.forename: Atsushi
authors.initials: A
authors.lastname: Okawa
authors.forename: Dan M
authors.initials: DM
authors.lastname: Spengler
authors.forename: Scott A
authors.initials: SA
authors.lastname: Guelcher
mesh_terms: D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry / Q000494:pharmacology*; D002130:Calcium Phosphates / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D017886:Durapatite / Q000737:chemistry / Q000494:pharmacology*; D005269:Femur / Q000000981:diagnostic imaging / Q000293:injuries*; D008297:Male; D008422:Materials Testing; D051379:Mice; D011140:Polyurethanes / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D055114:X-Ray Microtomography
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; D011140:Polyurethanes; C485817:beta-tricalcium phosphate; D017886:Durapatite