Surface Biofunctionalization of Silk Biomaterials Using Dityrosine Cross-Linking

Abstract

Biofunctionalization of silk biomaterial surfaces with extracellular matrix (ECM) molecules, cell binding peptides, or growth factors is important in a range of applications, including tissue engineering and development of implantable medical devices. Passive adsorption is the most common way to immobilize molecules of interest on preformed silk biomaterials but can lead to random molecular orientations and displacement from the surface, limiting their applications. Herein, we developed techniques for covalent immobilization of biomolecules using enzyme- or photoinitiated formation of dityrosine bonds between the molecule of interest and silk. Using recombinantly expressed domain V of the human basement membrane proteoglycan perlecan (rDV) as a model molecule, we demonstrated that rDV can be covalently immobilized via dityrosine cross-linking without the need to modify rDV or silk biomaterials. Dityrosine-based immobilization resulted in a different molecular orientation to passively absorbed rDV with less C- and N-terminal region exposure on the surface. Dityrosine-based immobilization supported functional rDV immobilization where immobilized rDV supported endothelial cell adhesion, spreading, migration, and proliferation. These results demonstrate the utility of dityrosine-based cross-linking in covalent immobilization of tyrosine-containing molecules on silk biomaterials in the absence of chemical modification, adding a simple and accessible technique to the silk biofunctionalization toolbox.

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Novel electrochemical platform based on C3N4-graphene composite for the detection of neuron-specific enolase as a biomarker for lung cancer

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Silk fibroin increases the elasticity of alginate-gelatin hydrogels and regulates cardiac cell contractile function in cardiac bioinks

“…An aqueous solution of SF was prepared from the silkworm Bombyx mori cocoon thread (purchased from Sato Yama, Japan) through a three-step procedure as per our previously established protocols [29,30]. Briefly, 5 g of delaminated silk samples were degummed using 0.02 M sodium carbonate (Na 2 CO 3 , Sigma Aldrich) in 2 l water at high temperature (90 • C-100 • C), to remove sericin from SF .…”