PVDF film tethered with RGD-click-poly(glycidyl methacrylate) brushes by combination of direct surface-initiated ATRP and click chemistry for improved cytocompatibility

Abstract

To enhance the cytocompatibility of polyvinylidene fluoride (PVDF) films, arginine–glycine–aspartic acid (RGD) peptide-click-poly(glycidyl methacrylate) (PGMA) polymer brushes were grafted onto the PVDF surface by the combination of surface-initiated atom transfer radical polymerization (ATRP) and click reaction. The direct initiation of the secondary fluorine atoms of PVDF backbone allowed for grafting of the PGMA brushes containing reactive epoxy groups. Subsequent introduction of the azide groups onto the side chain of PGMA brushes was achieved by the ring-open reaction of the epoxy groups with sodium azide. The cell adhesive RGD peptide was finally conjugated onto the PGMA brushes via alkyne-azide click reaction. Kinetic studies revealed that the PGMA chain growth from the PVDF surface was consistent with a “controlled” process, and that the amount of immobilized RGD peptide on the PGMA brushes increased with the concentration of the pendant azide groups. The specificity of cellular interactions of adipose tissue-derived stem cells (ASCs) on the functionalized PVDF films was investigated. Results demonstrated that cell adhesion and proliferation of ASCs were significantly improved on the RGD-immobilized PVDF substrates, and this improvement was positively correlated with the surface concentration of covalently-bonded RGD peptide. With the inherent superior chemical and mechanical properties of PVDF films and the biocompatible nature of cell-adhesive peptides, surface functionalized PVDF films are potentially useful for biomedical and tissue engineering applications.