title: Hydrophobicity as a design criterion for polymer scaffolds in bone tissue engineering.
abstract: Porous polymeric scaffolds play a key role in most tissue-engineering strategies. A series of non-degrading porous scaffolds was prepared, based on bulk-copolymerisation of 1-vinyl-2-pyrrolidinone (NVP) and n-butyl methacrylate (BMA), followed by a particulate-leaching step to generate porosity. Biocompatibility of these scaffolds was evaluated in vitro and in vivo. Furthermore, the scaffold materials were studied using the so-called demineralised bone matrix (DBM) as an evaluation system in vivo. The DBM, which is essentially a part of a rat femoral bone after processing with mineral acid, provides a suitable environment for ectopic bone formation, provided that the cavity of the DBM is filled with bone marrow prior to subcutaneous implantation in the thoracic region of rats. Various scaffold materials, differing with respect to composition and, hence, hydrophilicity, were introduced into the centre of DBMs. The ends were closed with rat bone marrow, and ectopic bone formation was monitored after 4, 6, and 8 weeks, both through X-ray microradiography and histology. The 50:50 scaffold particles were found to readily accommodate formation of bone tissue within their pores, whereas this was much less the case for the more hydrophilic 70:30 counterpart scaffolds. New healthy bone tissue was encountered inside the pores of the 50:50 scaffold material, not only at the periphery of the constructs but also in the center. Active osteoblast cells were found at the bone-biomaterial interfaces. These data indicate that the hydrophobicity of the biomaterial is, most likely, an important design criterion for polymeric scaffolds which should promote the healing of bone defects. Furthermore, it is argued that stable, non-degrading porous biomaterials, like those used in this study, provide an important tool to expand our comprehension of the role of biomaterials in scaffold-based tissue engineering approaches.
authors.affiliation: Center for Biomaterials Research, University of Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
authors.forename: Edwin J P
authors.initials: EJ
authors.lastname: Jansen
authors.forename: Raymond E J
authors.initials: RE
authors.lastname: Sladek
authors.forename: Hila
authors.initials: H
authors.lastname: Bahar
authors.forename: Avinoam
authors.initials: A
authors.lastname: Yaffe
authors.forename: Marion J
authors.initials: MJ
authors.lastname: Gijbels
authors.forename: Roel
authors.initials: R
authors.lastname: Kuijer
authors.forename: Sjoerd K
authors.initials: SK
authors.lastname: Bulstra
authors.forename: Nick A
authors.initials: NA
authors.lastname: Guldemond
authors.forename: Itzhak
authors.initials: I
authors.lastname: Binderman
authors.forename: Leo H
authors.initials: LH
authors.lastname: Koole
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology* / Q000502:physiology; D018786:Bone Substitutes / Q000737:chemistry*; D002448:Cell Adhesion / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D048091:Guided Tissue Regeneration / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D051379:Mice; D010012:Osteogenesis / Q000502:physiology*; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry*; D011205:Povidone / Q000031:analogs & derivatives* / Q000737:chemistry*; D051381:Rats; D011917:Rats, Inbred Lew; D012886:Skull / Q000166:cytology* / Q000502:physiology; D013499:Surface Properties; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D018786:Bone Substitutes; D011108:Polymers; D011109:Polymethacrylic Acids; C054377:butyl methacrylate-vinylpyrrolidone copolymer; D011205:Povidone