Polyphenols promote stem cell surface adaptation onto low-adhesion chitosan-titanium through protein synthesis and cytoskeletal remodeling

Implant surface modification aims to facilitate integration by enhancing cell-material interactions at the interface. Accordingly, a Ti6Al4V alloy was chemically treated to obtain a microtextured topography with a high density of reactive -OH groups, then coated with chitosan and finally functionalized with a polyphenol extract from white grape seeds. Chitosan was crosslinked with sodium tripolyphosphate to reduce swelling. The extract and the functionalization solution were analyzed through HPLC, DLS, zeta potential, Folin-Ciocalteu assay, and UV-Vis spectroscopy. The functionalized Ti alloys were characterized through fluorescence and XPS analysis. The biological characterization using human bone marrow-derived stem cells (hBM-MSCs) showed low adhesion on chitosan, while polyphenols significantly improved surface colonization. Immunocompatibility studies using peripheral blood mononuclear cells excluded alterations in the balance of immune cell subsets due to the interaction with the polyphenol-functionalized titanium. Proteomic studies were performed on proteins expressed by hBM-MSCs and on proteins adsorbed from a rich protein source such as fetal bovine serum (FBS). Results demonstrated that polyphenols enhanced protein synthesis and extracellular matrix organization for hBM-MSCs, while they significantly promoted the adsorption of proteins from FBS.