Epigallocatechin-gallate tailors the cell adhesivity of fibronectin coatings in oxidation and concentration-dependent manner

Fibronectin is an extracellular matrix component that plays a significant role in many physiological processes, such as cell adhesion, growth, differentiation, and migration. In this study, we revealed the interaction between this important protein and the widely studied natural active substance green tea polyphenol epigallocatechin-gallate (EGCG) and its oxidized form. Furthermore, we investigated the kinetics of cancer cell adhesion on the polyphenol-treated fibronectin coatings. We applied a high- throughput, label-free optical biosensor capable of monitoring the above processes in real time with an excellent signal-to-noise ratio. Our results show that EGCG and its oxidized form bind to fibronectin in a concentration-dependent manner and can form multilayers as well. Furthermore, both polyphenol forms inhibited cellular adhesion, however, the effect was more pronounced in the case of the oxidized form. The results were compared to the measurements performed on bare biosensor surfaces without fibronectin, and the roles of oxidation were investigated. It is suggested that the polyphenols can interact and block important cell adhesion protein motifs and affect the rigidity of the layers as well. Moreover, a novel molecular scale active mechanism involving the disulfide bridges of fibronectin was proposed to explain the recorded kinetic signals and highlight that these proteins can be active participants in the molecular scale transformations affecting adhesion