title: A hybrid silk/RADA-based fibrous scaffold with triple hierarchy for ligament regeneration.
abstract: While silk-based microfibrous scaffolds possess excellent mechanical properties and have been used for ligament tissue-engineering applications, the microenvironment in these scaffolds is not biomimetic. We hypothesized that coating a hybrid silk scaffold with an extracellular matrix (ECM)-like network of self-assembling peptide nanofibers would provide a biomimetic three-dimensional nanofibrous microenvironment and enhance ligament tissue regeneration after bone marrow-derived mesenchymal stem cell (BMSC)-seeding. A novel scaffold possessing a triple structural hierarchy comprising macrofibrous knitted silk fibers, a silk microsponge, and a peptide nanofiber mesh was developed by coating self-assembled RADA16 peptide nanofibers on a silk microfiber-reinforced-sponge scaffold. Compared with the uncoated control, RADA-coated scaffolds showed enhanced BMSC proliferation, metabolism, and fibroblastic differentiation during the 3 weeks of culture. BMSC-seeded RADA-coated scaffolds showed an increasing temporal expression of key fibroblastic ECM proteins (collagen type I and III, tenascin-C), with a significantly higher tenascin-C expression compared with the controls. BMSC-seeded RADA-coated scaffolds also showed a temporal increase in total collagen and glycosaminoglycan production (the amount produced being higher than in control scaffolds) during 3 weeks of culture, and possessed 7% higher maximum tensile load compared with the BMSC-seeded control scaffolds. The results indicate that the BMSC-seeded RADA-coated hybrid silk scaffold system has the potential for use in ligament tissue-engineering applications.
authors.affiliation: Department of Bioengineering, National University of Singapore, Engineering Drive 1, Singapore.
authors.forename: Kelei
authors.initials: K
authors.lastname: Chen
authors.forename: Sambit
authors.initials: S
authors.lastname: Sahoo
authors.forename: Pengfei
authors.initials: P
authors.lastname: He
authors.forename: Kian Siang
authors.initials: KS
authors.lastname: Ng
authors.forename: Siew Lok
authors.initials: SL
authors.lastname: Toh
authors.forename: James C H
authors.initials: JC
authors.lastname: Goh
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D012831:Bombyx; D002448:Cell Adhesion / Q000187:drug effects; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D003094:Collagen / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006025:Glycosaminoglycans / Q000378:metabolism; D008022:Ligaments / Q000187:drug effects* / Q000502:physiology*; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D010455:Peptides / Q000494:pharmacology*; D011817:Rabbits; D012038:Regeneration / Q000187:drug effects*; D047011:Silk / Q000737:chemistry*; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D006025:Glycosaminoglycans; D010455:Peptides; C546681:RADA16-I; D047011:Silk; D003094:Collagen