title: The influence of specific binding of collagen-silk chimeras to silk biomaterials on hMSC behavior.
abstract: Collagen-like proteins in the bacteria Streptococcus pyogenes adopt a triple-helix structure with a thermal stability similar to that of animal collagens, can be expressed in high yield in Escherichia coli and can be easily modified through molecular biology techniques. However, potential applications for such recombinant collagens are limited by their lack of higher order structure to achieve the physical properties needed for most biomaterials. To overcome this problem, the S. pyogenes collagen domain was fused to a repetitive Bombyx mori silk consensus sequence, as a strategy to direct specific non-covalent binding onto solid silk materials whose superior stability, mechanical and material properties have been previously established. This approach resulted in the successful binding of these new collagen-silk chimeric proteins to silk films and porous scaffolds, and the binding affinity could be controlled by varying the number of repeats in the silk sequence. To explore the potential of collagen-silk chimera for regulating biological activity, integrin (Int) and fibronectin (Fn) binding sequences from mammalian collagens were introduced into the bacterial collagen domain. The attachment of bioactive collagen-silk chimeras to solid silk biomaterials promoted hMSC spreading and proliferation substantially in comparison to the controls. The ability to combine the biomaterial features of silk with the biological activities of collagen allowed more rapid cell interactions with silk-based biomaterials, improved regulation of stem cell growth and differentiation, as well as the formation of artificial extracellular matrices useful for tissue engineering applications.
authors.affiliation: Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: An
authors.forename: Teresa M
authors.initials: TM
authors.lastname: DesRochers
authors.forename: Guokui
authors.initials: G
authors.lastname: Qin
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Xia
authors.forename: Geetha
authors.initials: G
authors.lastname: Thiagarajan
authors.forename: Barbara
authors.initials: B
authors.lastname: Brodsky
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism*; D012831:Bombyx / Q000737:chemistry / Q000235:genetics; D002448:Cell Adhesion; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D003001:Cloning, Molecular; D003094:Collagen / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D008969:Molecular Sequence Data; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D047011:Silk / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013297:Streptococcus pyogenes / Q000737:chemistry / Q000235:genetics; D054457:Tissue Scaffolds / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D001672:Biocompatible Materials; D011993:Recombinant Fusion Proteins; D047011:Silk; D003094:Collagen