title: Cotton-wool-like bioactive glasses for bone regeneration.
abstract: Inorganic sol-gel solutions were electrospun to produce the first bioactive three-dimensional (3-D) scaffolds for bone tissue regeneration with a structure like cotton-wool (or cotton candy). This flexible 3-D fibrous structure is ideal for packing into complex defects. It also has large inter-fiber spaces to promote vascularization, penetration of cells and transport of nutrients throughout the scaffold. The 3-D fibrous structure was obtained by electrospinning, where the applied electric field and the instabilities exert tremendous force on the spinning jet, which is required to be viscoelastic to prevent jet break up. Previously, polymer binding agents were used with inorganic solutions to produce electrospun composite two-dimensional fibermats, requiring calcination to remove the polymer. This study presents novel reaction and processing conditions for producing a viscoelastic inorganic sol-gel solution that results in fibers by the entanglement of the intermolecularly overlapped nanosilica species in the solution, eliminating the need for a binder. Three-dimensional cotton-wool-like structures were only produced when solutions containing calcium nitrate were used, suggesting that the charge of the Ca(2+) ions had a significant effect. The resulting bioactive silica fibers had a narrow diameter range of 0.5-2μm and were nanoporous. A hydroxycarbonate apatite layer was formed on the fibers within the first 12h of soaking in simulated body fluid. MC3T3-E1 preosteoblast cells cultured on the fibers showed no adverse cytotoxic effect and they were observed to attach to and spread in the material.
authors.affiliation: Department of Materials, Imperial College London, South Kensington, London SW7 2AZ, UK. Electronic address: gowsh.p@imperial.ac.uk.
authors.forename: G
authors.initials: G
authors.lastname: Poologasundarampillai
authors.affiliation: Department of Materials, Imperial College London, South Kensington, London SW7 2AZ, UK.
authors.forename: D
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Materials, Imperial College London, South Kensington, London SW7 2AZ, UK.
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Nakamura
authors.affiliation: School of Materials, The University of Manchester, Oxford Rd., Manchester M13 9PL, UK.
authors.forename: R
authors.initials: R
authors.lastname: Bradley
authors.affiliation: School of Materials, The University of Manchester, Oxford Rd., Manchester M13 9PL, UK.
authors.forename: P D
authors.initials: PD
authors.lastname: Lee
authors.affiliation: Department of Materials, Imperial College London, South Kensington, London SW7 2AZ, UK; Department of Bioengineering, Imperial College London, South Kensington, London SW7 2AZ, UK.
authors.forename: M M
authors.initials: MM
authors.lastname: Stevens
authors.affiliation: Department of Materials, Imperial College London, South Kensington, London SW7 2AZ, UK.
authors.forename: D S
authors.initials: DS
authors.lastname: McPhail
authors.affiliation: Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kasuga
authors.affiliation: Department of Materials, Imperial College London, South Kensington, London SW7 2AZ, UK.
authors.forename: J R
authors.initials: JR
authors.lastname: Jones
mesh_terms: D016475:3T3 Cells; D000818:Animals; D040761:Biomimetic Materials / Q000138:chemical synthesis; D001826:Body Fluids / Q000737:chemistry; D001861:Bone Regeneration / Q000502:physiology; D002448:Cell Adhesion / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D032561:Cotton Fiber; D005898:Glass / Q000737:chemistry; D003368:Gossypium / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D051379:Mice; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D054457:Tissue Scaffolds; D014935:Wool / Q000737:chemistry*
chemical_list: D012822:Silicon Dioxide
keywords: 3-D cotton-wool-like structure; Bone regeneration scaffold; Electrospinning; Inorganic fibers; Sol–gel