title: Oxygen diffusion in marine-derived tissue engineering scaffolds.
abstract: This paper addresses the computation of the effective diffusivity in new bioactive glass (BG) based tissue engineering scaffolds. High diffusivities facilitate the supply of oxygen and nutrients to grown tissue as well as the rapid disposal of toxic waste products. The present study addresses required novel types of bone tissue engineering BG scaffolds that are derived from natural marine sponges. Using the foam replication method, the scaffold geometry is defined by the porous structure of Spongia Agaricina and Spongia Lamella. These sponges present the advantage of attaining scaffolds with higher mechanical properties (2-4 MPa) due to a decrease in porosity (68-76%). The effective diffusivities of these structures are compared with that of conventional scaffolds based on polyurethane (PU) foam templates, characterised by high porosity (>90%) and lower mechanical properties (>0.05 MPa). Both the spatial and directional variations of diffusivity are investigated. Furthermore, the effect of scaffold decomposition due to immersion in simulated body fluid (SBF) on the diffusivity is addressed. Scaffolds based on natural marine sponges are characterised by lower oxygen diffusivity due to their lower porosity compared with the PU replica foams, which should enable the best oxygen supply to newly formed bone according the numerical results. The oxygen diffusivity of these new BG scaffolds increases over time as a consequence of the degradation in SBF.
authors.affiliation: Department of Materials Science and Engineering, Institute of Biomaterials, University of Erlangen-Nuremberg, 91058, Erlangen, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Boccardi
authors.forename: I V
authors.initials: IV
authors.lastname: Belova
authors.forename: G E
authors.initials: GE
authors.lastname: Murch
authors.forename: A R
authors.initials: AR
authors.lastname: Boccaccini
authors.forename: T
authors.initials: T
authors.lastname: Fiedler
mesh_terms: D000818:Animals; D016880:Anisotropy; D001672:Biocompatible Materials / Q000737:chemistry; D001861:Bone Regeneration; D002516:Ceramics / Q000737:chemistry; D004058:Diffusion; D005898:Glass / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009010:Monte Carlo Method; D010100:Oxygen / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D011161:Porifera / Q000737:chemistry*; D016062:Porosity; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds / Q000737:chemistry*; D055114:X-Ray Microtomography
chemical_list: D001672:Biocompatible Materials; D011140:Polyurethanes; C425330:bioactive glass 45S5; D010100:Oxygen