Interaction of Plasma Deposited HMDSO-Based Coatings with Fibrinogen and Human Blood Plasma: The Correlation between Bulk Plasma, Surface Characteristics and Biomolecule Interaction

The success of a biomaterial depends on the nature of interaction and the progressive reaction between the biological components and the surface of the biomaterial. In order to control the interaction between the biomaterial and biological component, it is necessary to understand the factors that influence the protein adsorption and cell proliferation. Surface chemistry plays a crucial role in the success of any blood contacting biomaterial. Plasma enhanced chemical vapour deposition (PECVD) is an interesting commonly used technique for tailoring surface characteristics while retaining bulk material properties. Two different films, namely polymer-like and silica-like coatings, with varying surface characteristics have been deposited from hexamethyldisiloxane, by PECVD, on 316L stainless steel. A correlation between the bulk plasma, interfacial adhesion of the coating to 316L steel, surface characteristics and biomolecule interaction is presented in this work The interfacial adhesion strength analysis demonstrated that silica-like coatings have higher adhesion strength to 316L stainless steel than polymer-like coatings, caused due to the formation of a strong Fe-O-Si and Cr-O-Si bonds. It was observed that the effect of nanoscale surface roughness (dose to 6 nm) was less significant, and that the surface chemistry played a significant role in governing the fibrinogen adsorption. Highest fibrinogen adsorption on plain steel was due to the electrostatic interaction of the metal oxide layer with the protein Hydrophobicity of the polymer like film resulted in a higher fibrinogen binding than the silica-like films.