title: Clay enriched silk biomaterials for bone formation.
abstract: The formation of silk protein/clay composite biomaterials for bone tissue formation is described. Silk fibroin serves as an organic scaffolding material offering mechanical stability suitable for bone-specific uses. Clay montmorillonite (Cloisite® Na(+)) and sodium silicate are sources of osteoinductive silica-rich inorganic species, analogous to bioactive bioglass-like bone repair biomaterial systems. Different clay particle-silk composite biomaterial films were compared with silk films doped with sodium silicate as controls for the support of human bone marrow derived mesenchymal stem cells in osteogenic culture. The cells adhered to and proliferated on the silk/clay composites over 2 weeks. Quantitative real time polymerase chain reaction analysis revealed increased transcript levels for alkaline phosphatase, bone sialoprotein, and collagen type 1 osteogenic markers in the cells cultured on the silk/clay films in comparison with the controls. Early evidence of bone formation based on collagen deposition at the cell-biomaterial interface was also found, with more collagen observed for the silk films with higher contents of clay particles. The data suggest that silk/clay composite systems may be useful for further study for bone regenerative needs.
authors.affiliation: Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA.
authors.forename: Aneta J
authors.initials: AJ
authors.lastname: Mieszawska
authors.forename: Jabier Gallego
authors.initials: JG
authors.lastname: Llamas
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Vaiana
authors.forename: Madhavi P
authors.initials: MP
authors.lastname: Kadakia
authors.forename: Rajesh R
authors.initials: RR
authors.lastname: Naik
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
mesh_terms: D000538:Aluminum Silicates / Q000494:pharmacology*; D001546:Bentonite / Q000494:pharmacology; D001672:Biocompatible Materials / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D000077215:Clay; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D010012:Osteogenesis / Q000187:drug effects* / Q000235:genetics; D010078:Oxazines / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D047011:Silk / Q000494:pharmacology*; D014966:Xanthenes / Q000378:metabolism
chemical_list: D000538:Aluminum Silicates; D001672:Biocompatible Materials; D010078:Oxazines; D012333:RNA, Messenger; D047011:Silk; D014966:Xanthenes; D001546:Bentonite; C005843:resazurin; D000077215:Clay