title: Foamed surfactant solution as a template for self-setting injectable hydroxyapatite scaffolds for bone regeneration.
abstract: The application of minimally invasive surgical techniques in the field of orthopaedic surgery has created a growing need for new injectable synthetic materials that can be used for bone grafting. In this work a novel fully synthetic injectable calcium phosphate foam was developed by mixing alpha-tricalcium phosphate (alpha-TCP) powder with a foamed polysorbate 80 solution. Polysorbate 80 is a non-ionic surfactant approved for parenteral applications. The foam was able to retain the porous structure after injection provided that the foamed paste was injected shortly after mixing (typically 2.5 min), and set through the hydrolysis of alpha-TCP to a calcium-deficient hydroxyapatite, thus producing a hydroxyapatite solid foam in situ. The effect of different processing parameters on the porosity, microstructure, injectability and mechanical properties of the hydroxyapatite foams was analysed, and the ability of the pre-set foam to support osteoblastic-like cell proliferation and differentiation was assessed. Interestingly, the concentration of surfactant needed to obtain the foams was lower than that considered safe in drug formulations for parenteral administration. The possibility of combining bioactivity, injectability, macroporosity and self-setting ability in a single fully synthetic material represents a step forward in the design of new materials for bone regeneration compatible with minimally invasive surgical techniques.
authors.affiliation: Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), Av. Diagonal 647, E08028 Barcelona, Spain.
authors.forename: E B
authors.initials: EB
authors.lastname: Montufar
authors.forename: T
authors.initials: T
authors.lastname: Traykova
authors.forename: C
authors.initials: C
authors.lastname: Gil
authors.forename: I
authors.initials: I
authors.lastname: Harr
authors.forename: A
authors.initials: A
authors.lastname: Almirall
authors.forename: A
authors.initials: A
authors.lastname: Aguirre
authors.forename: E
authors.initials: E
authors.lastname: Engel
authors.forename: J A
authors.initials: JA
authors.lastname: Planell
authors.forename: M P
authors.initials: MP
authors.lastname: Ginebra
mesh_terms: D001861:Bone Regeneration / Q000502:physiology*; D018786:Bone Substitutes / Q000008:administration & dosage* / Q000737:chemistry*; D002460:Cell Line; D004337:Drug Carriers / Q000737:chemistry; D004339:Drug Compounding / Q000379:methods; D005740:Gases / Q000737:chemistry; D006801:Humans; D006882:Hydroxyapatites / Q000008:administration & dosage* / Q000737:chemistry*; D007267:Injections; D008422:Materials Testing; D010006:Osteoblasts / Q000502:physiology; D012996:Solutions / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*; D054457:Tissue Scaffolds
chemical_list: D018786:Bone Substitutes; D004337:Drug Carriers; D005740:Gases; D006882:Hydroxyapatites; D012996:Solutions; D013501:Surface-Active Agents