Bacterial adhesion to titanium-oxy-nitride (TiNOX) coatings with different resistivities: a novel approach for the development of biomaterials

In this study the quantitative adhesion of a strain of Staphylococcus epidermidis, Streptococcus mutans and Pseudomonas aeruginosa to and the ease of removal from different TiNOX coatings was investigated by means of a parallel plate flow chamber and in situ image analysis. Quality of adhesion was determined by counting bacteria which remained attached to the surface after exposure to an air–liquid interface. S. epidermidis and S. mutans showed a bipolar adhesion pattern with highest numbers of adhesion at low and high resistivity with lowest adhesions at a resistivity of 104 μΩ cm. P. aeruginosa was the least adherent organism. These results indicate that the affinity of these three strains under the current experimental conditions is minimal for TiNOX coatings with a specific resistivity. TiNOX coatings with pre-adsorbed fibrinogen showed different numbers of S. epidermidis adhered to the different coatings. However, the affinity of this strain for fibrinogen-coated TiNOX remains low when the resistivity is around 104 μΩ cm. This indicates that the specific influence of the resistivities of the TiNOX coatings is transferred through the adsorbed fibrinogen film to the interface with adhering bacteria.