title: New generation poly(ε-caprolactone)/gel-derived bioactive glass composites for bone tissue engineering: Part I. Material properties.
abstract: Poly(ε-caprolactone) (PCL) based composite films containing 12 and 21vol.% bioactive glass (SBG) microparticles were prepared by solvent casting method. Two gel-derived SBGs of SiO2-CaO-P2O5 system differing in SiO2 and CaO contents were applied (mol%): S2: 80SiO2, 16CaO, 4P2O5 and A2: 40SiO2, 54CaO, 6P2O5. The surfaces of the films in contact with Petri dish and exposed to the gas phase during casting were denoted as GS and AS, respectively. Both surfaces of films were characterised in terms of their morphology, micro- and nano-topography as well as wettability. Also mechanical properties (tensile strength, Young's modulus) and PCL matrix crystallinity (degree of crystallinity, crystal size) were evaluated. Degradation behaviour was examined by incubation of materials in UHQ-water at 37°C for 56weeks. The crystallinity, melting temperature and mass loss of incubated materials and pH changes of water were monitored. Furthermore, proliferation of MG-63 osteoblastic cells by direct contact and cytotoxic effect of obtained materials were investigated. Results showed that opposite surfaces of the same polymer and composite films differ in studied surface parameters. The addition of SBG particles into PCL matrix improves nano- and micro-roughness of both surfaces, enhances the hydrophilicity of GS surfaces (~67° for 21A2-PCL compared to ~78° for pure PCL) and also makes AS surface more hydrophobic (~94° for 21S2-PCL compared to ~86° for pure PCL). The nucleation density of PCL was increased with increasing content of SBG particles, which results in the large number of fine spherulites on composite AS surfaces observed using polarized optical (POM), scanning electron (SEM), and atomic force (AFM) microscopies. Higher content of SBG particles causes a notable increase of Young's modulus (from 0.38GPa for pure PCL, 0.90GPa for 12A2-PCL to 1.31GPa for 21A2-PCL), which also depends on SBG chemical composition. After 56-week degradation test, considerably higher crystallinity increase (Δχc ~148% for 21S2-PCL, ~81% for 21A2-PCL) and weight loss (~17% for both) were found for composite materials, depending on SBG composition, in contrast to value variations for pure PCL film (Δχc ~43%, weight loss ~1.6%). Furthermore, it seems that both SBG could neutralize acidic degradation by-products of PCL at later incubation stages. Obtained SBG-PCL composites show excellent biocompatibility, support cell proliferation also may modulate cell response depending on the glass composition. The results indicate the possibility to use different contents and/or chemical compositions of SBG to obtain composite materials with various, but controlled, surface and mechanical properties as well as degradation kinetics.
authors.affiliation: AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Department of Glass Technology and Amorphous Coatings, 30 Mickiewicza Ave., 30-059 Krakow, Poland. Electronic address: dziadek@agh.edu.pl.
authors.forename: Michal
authors.initials: M
authors.lastname: Dziadek
authors.affiliation: Jagiellonian University, Collegium Medicum, Department of Cytobiology, 9 Medyczna St., 30-688 Krakow, Poland. Electronic address: elzbieta.menaszek@uj.edu.pl.
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Menaszek
authors.affiliation: AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Department of Glass Technology and Amorphous Coatings, 30 Mickiewicza Ave., 30-059 Krakow, Poland. Electronic address: b.zagrajczuk@gmail.com.
authors.forename: Barbara
authors.initials: B
authors.lastname: Zagrajczuk
authors.affiliation: AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Department of Glass Technology and Amorphous Coatings, 30 Mickiewicza Ave., 30-059 Krakow, Poland. Electronic address: pawlikj@agh.edu.pl.
authors.forename: Justyna
authors.initials: J
authors.lastname: Pawlik
authors.affiliation: AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Department of Glass Technology and Amorphous Coatings, 30 Mickiewicza Ave., 30-059 Krakow, Poland. Electronic address: cholewa@agh.edu.pl.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Cholewa-Kowalska
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D001861:Bone Regeneration; D001842:Bone and Bones / Q000737:chemistry*; D055119:Elastic Modulus; D005782:Gels / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D008422:Materials Testing / Q000379:methods; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013718:Tensile Strength; D023822:Tissue Engineering / Q000379:methods
chemical_list: D001672:Biocompatible Materials; D005782:Gels; D011091:Polyesters; D011108:Polymers; C016240:polycaprolactone; D012822:Silicon Dioxide
keywords: Biocompatibility; Biodegradation; Crystallinity; Mechanical properties; Polymer-ceramic composites; Solvent-cast films; Surface properties