title: Poly(propylene fumarate) reinforced dicalcium phosphate dihydrate cement composites for bone tissue engineering.
abstract: Calcium phosphate cements have many desirable properties for bone tissue engineering, including osteoconductivity, resorbability, and amenability to rapid prototyping-based methods for scaffold fabrication. In this study, we show that dicalcium phosphate dihydrate (DCPD) cements, which are highly resorbable but also inherently weak and brittle, can be reinforced with poly(propylene fumarate) (PPF) to produce strong composites with mechanical properties suitable for bone tissue engineering. Characterization of DCPD-PPF composites revealed significant improvements in mechanical properties for cements with a 1.0 powder to liquid ratio. Compared with nonreinforced controls, flexural strength improved from 1.80 ± 0.19 MPa to 16.14 ± 1.70 MPa, flexural modulus increased from 1073.01 ± 158.40 MPa to 1303.91 ± 110.41 MPa, maximum displacement during testing increased from 0.11 ± 0.04 mm to 0.51 ± 0.09 mm, and work of fracture improved from 2.74 ± 0.78 J/m(2) to 249.21 ± 81.64 J/m(2) . To demonstrate the utility of our approach for scaffold fabrication, 3D macroporous scaffolds were prepared with rapid prototyping technology. Compressive testing revealed that PPF reinforcement increased scaffold strength from 0.31 ± 0.06 MPa to 7.48 ± 0.77 MPa. Finally, 3D PPF-DCPD scaffolds were implanted into calvarial defects in rabbits for 6 weeks. Although the addition of mesenchymal stem cells to the scaffolds did not significantly improve the extent of regeneration, numerous bone nodules with active osteoblasts were observed within the scaffold pores, especially in the peripheral regions. Overall, the results of this study suggest that PPF-DCPD composites may be promising scaffold materials for bone tissue engineering.
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47908, USA.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Alge
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Bennett
authors.forename: Trevor
authors.initials: T
authors.lastname: Treasure
authors.forename: Sherry
authors.initials: S
authors.lastname: Voytik-Harbin
authors.forename: W Scott
authors.initials: WS
authors.lastname: Goebel
authors.forename: Tien-Min Gabriel
authors.initials: TM
authors.lastname: Chu
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001843:Bone Cements; D001842:Bone and Bones; D002130:Calcium Phosphates / Q000737:chemistry*; D005650:Fumarates / Q000737:chemistry*; D008297:Male; D011126:Polypropylenes / Q000737:chemistry*; D011817:Rabbits; D023822:Tissue Engineering; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D001843:Bone Cements; D002130:Calcium Phosphates; D005650:Fumarates; D011126:Polypropylenes; C097850:poly(propylene fumarate); C494366:calcium phosphate, dibasic, dihydrate