Functionalization of Polymer Surfaces to Increase Fibronectin Adhesion

Functionalization of Polymer Surfaces To Increase Fibronectin Adhesion 

The intimate contact between implant and tissue is a decisive prerequisite for the biocompatibility of long-term implants in soft tissue application. To achieve this an interface must be created which provokes optimal cell growth. As for the 

Fibrin binding Heparin binding Cell binding domain domain domain 

Fibronectin is an adhesion protein like laminin, vitronectin, and von Wille-brand factor, which are synthesized by the cells themselves to build up the ECM. The glycoprotein fibronectin with a molecular weight between 220,000 and 250,000 consists of two similar subunits, which are connected close to their C-terminus by disulfide bridges. The subunits are composed of functional domains [121]. The cell binding domain with the characteristic sequence Gly-Arg-Gly-Asp-Ser (GRGDS) is of special interest [122]. Models of the subunit of the fibronectin molecule and its cell binding domain are presented in Fig. 21. 

The objective of functionalization of polymer surfaces is to create a surface that shows high fibronectin adsorption and, at the same time, guarantees the availability of its cell binding domains. Hydrophilic surfaces favor adsorption of fibronectin and fibronectin shows high affinity to sulfonic acid and sulfate groups [123]. This is the reason why the fimctionalization of hydrophobic polymer surfaces is carried out by SO2 plasma treatment, so that not only the hy-drophilicity is increased but oxidized sulfur groups are also introduced (Fg.22). 

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