Bio‐functionalized star PEG‐coated PVDF surfaces for cytocompatibility‐improved implant components

Abstract

Unmodified and GRGDS peptide-modified six arm PEG star based hydrogels (Star PEG) have been applied as a multifunctional, easy to handle coating system for textile polyvinylidene fluoride (PVDF) structures, which prevent unspecific protein and cell adsorption and control-specific cell adhesion. The reactive isocyanate-terminated Star PEG has been successfully applied to ammonia-plasma treated two- and three-dimensional PVDF surfaces. Easy modification of the surface hydrogel by mixing in of GRGDS peptide during the coating step or subsequent coupling of GRGDS was determined by TOF-SIMS. Unmodified and GRGDS-functionalized hydrogel surfaces show distinct protein repellency, as demonstrated by fluorescence microscopy after incubation with fluorescent labeled proteins and Surface MALDI-TOF-Mass Spectroscopy. Cell culture experiments with primary human dermal fibroblasts, primary fetal rat fibroblasts, and human osteoblasts on GRGDS and/or KRSR Star PEG-modified two- and three-dimensional substrates show advancement in cell adhesion and proliferation compared with untreated PVDF surfaces, whereas pure star PEG-coated surfaces show no cell adhesion. The combination of protein and cell repellent properties with specific biofunctionality and easy application of the coatings will enable their application for 3D-scaffolds.

Stable Biochemically Micro-patterned Hydrogel Layers Control Specific Cell Adhesion and Allow Long Term Cyclic Tensile Strain Experiments

“…The resulting hydrogel coatings can be (covalently) functionalized with cell adhesive peptide sequences or complete ECM proteins such as FN. This results in mechanically deformable substrates with specific bio‐activation for selective cell adhesion . In this study, we investigated the long‐term stability of a) the hydrogel coating and b) of the μCP FN under standard cell culture conditions and simultaneous application of uniaxial CTS over 2 d. We further used these surfaces to investigate the effect of CTS on adherent HDFs on FN micro‐patterns where the line pattern was arranged in different angles with respect to the direction of CTS application.…”

“…Six‐armed star shaped PEG‐based pre‐polymers have reactive isocyanate (NCO) groups at the distal ends of the six arms (NCO‐sP(EO‐ stat ‐PO)). This PEG system has been applied as a multifunctional, self‐crosslinking, and robust hydrogel coating for inorganic substrates such as glass and silicone as well as for polymer systems like poly(vinylidene fluoride) (PVDF) or PDMS . The sP(EO‐ stat ‐PO) layers minimize unspecific protein adsorption and prevent adhesion of numerous cell types .…”

“…The sP(EO‐ stat ‐PO) layers minimize unspecific protein adsorption and prevent adhesion of numerous cell types . Direct covalent bio‐functionalization of the hydrogel layers, for example, through modification of freshly prepared and still NCO functional coatings is possible and enables controlled cell adhesion to the modified surfaces after hydrolysis of the remaining NCO groups . Bio‐functionalization is mainly performed with short peptides derived from ECM proteins, whole ECM proteins such as fibronectin (FN) or oligosaccharides (LacNAc) that bind glycosylated ECM proteins .…”

“…Direct covalent bio‐functionalization of the hydrogel layers, for example, through modification of freshly prepared and still NCO functional coatings is possible and enables controlled cell adhesion to the modified surfaces after hydrolysis of the remaining NCO groups . Bio‐functionalization is mainly performed with short peptides derived from ECM proteins, whole ECM proteins such as fibronectin (FN) or oligosaccharides (LacNAc) that bind glycosylated ECM proteins . These biologically active compounds can be chemically bound onto the hydrogel coating in micro‐patterns through μCP .…”

“…These biologically active compounds can be chemically bound onto the hydrogel coating in micro‐patterns through μCP . For long‐term stability of the hydrogel films, polymeric materials such as PVDF or PDMS need to be initially activated by ammonia plasma before they can be coated with NCO‐sP(EO‐ stat ‐PO) . Coating of PDMS after plasma activation yields covalent and permanent binding of the NCO‐sP(EO‐ stat ‐PO) since the cross‐linking between precursors of this star‐shaped PEG‐based layer chemically quenches the reorganization process of PDMS.…”