A novel star PEG–derived surface coating for specific cell adhesion

Abstract

In this study a novel approach for the coating and functionalization of substrates for cell culture and tissue engineering is presented. Glass, silicon, and titanium panes were coated with an ultrathin film (30 +/- 5 nm) of reactive star-shaped poly(ethylene glycol) prepolymers (Star PEG). Homogeneity of the films was checked by optical microscopy and scanning force microscopy. These coatings prevent unspecific protein adsorption as monitored by fluorescence microscopy and ellipsometry. In order to allow specific cell adhesion the films were modified with linear RGD peptides (gRGDsc) in different concentrations. After sterilization, fibroblast, SaOS, and human mesenchymal stem cells (hMSC) were seeded on these substrates. Cell adhesion, spreading, and survival was observed for up to 30 days on linear RGD peptide (gRGDsc)-modified coatings, whereas no cell adhesion could be detected on unmodified Star PEG layers. By variation of the RGD concentration within the film the amount of cells that became adhesive could be controlled. When differentiation conditions are used for cultivation of hMSCs the cells show the expression of osteogenic marker genes after 14 days which is comparable to cultivation on cell culture plastic. Thus, the Star PEG/RGD film did not negatively influence the differentiation process. The high flexibility of the system considering the incorporation of biologically active compounds opens a broad field of future experiments.

Multifunctional biomaterial coatings: synthetic challenges and biological activity

“…In absence of RGD, PEGylated surfaces showed decreased protein and cell adhesion. Moreover, it was demonstrated that human mesenchymal stem cells could undergo osteogenic differentiation on RGD-PEG modified surfaces (Groll et al, 2005). Another approach uses the affinity of poly-lysine to several surfaces to graft PEG, which is modified with a linear RGD (GCRGYGRGDSPG) peptide via thiol addition to vinyl sulfones (Table 3, line a).…”

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“…[26][27][28][29][30] Further insight into its chemistry can be explored to modify these gels to provide sites for cell adhesion or extracellular matrix (ECM) molecules to allow cells to infiltrate into these scaffolds and thereby enhancing its potential applications. 26,[31][32][33][34][35] Poly (ethylene-co-vinylacetate): Poly (ethylene-covinyl acetate) (EVA) is a non-degradable, biocompatible and commercially available polymer. It has been extensively used for drug delivery applications, [36][37][38][39] while more recently it has been investigated for neural tissue engineering applications, such as repair of peripheral nerve injury.…”

NCO-sP(EO-stat-PO) surface coatings preserve biochemical properties of RGD peptides

“…The preparation of the star polymers has been described elsewhere (17). Glass substrates (d=18 mm) were coated as described earlier (19).…”

“…This solution was mixed with the star polymer solution in 1 ml THF. The film formation was then done as described (19). The linear gRGDsc peptide was provided by Harm-Anton Klok (EPFL Lausanne) and the cyclic RGDfK peptide was prepared as previously described (20).…”

“…This feature also reduces bacterial adhesion and creates additional antimicrobial properties (18). Because of the unique switch from the chemically reactive isocyanate groups to an inert polymer layer, during the NCO-sP(EO-stat-PO) layer preparation, an easy integration of cell-binding supporting RGD peptides was demonstrated (19).…”