Improving cell adhesion: development of a biosensor for cell behaviour monitoring by surface grafting of sulfonic groups onto a thermoplastic polyurethane.

The surface properties of a material in combination with the mechanical properties are responsible for the material performance in a biological environment as well as the behaviour of the cells which contact with the material. Surface properties such as chemical, physical, biological play an important role in the biomaterials filed. In this work, the surface of a thermoplastic polyurethane film (Elastollan(®)1180A50) was tailored with sulfonic groups by grafting [2-(methacryloxyl)ethyl]-dimethyl-(3-sulfopropyl)-ammonium hydroxide (SB) after a previous surface activation either by Argon plasma or by ultra-violet irradiation. This surface modification had the purpose of improving cell adhesion in order to develop a biosensor able to monitor cell behaviour. The surfaces were characterized by X-ray photoelectron spectroscopy, by atomic force microscopy and by contact angle measurements in order to evaluate the efficiency of the modification. Additionally, blood compatibility studies and cell adhesion tests with human bone marrow cells were performed. These methods allowed the grafting of SB and the results indicate that a higher density of grafting was achieved with previous surface plasma treatment than with UV irradiation. However, for both techniques, the presence of SB functional groups led to a decrease of hydrophobicity and roughness of the surface, together with an improvement of the materials biological performance.