Atomic force microscopy probing platelet activation behavior on titanium nitride nanocoatings for biomedical applications

Abstract 

There is increasing interest in developing novel coatings to enhance the biocompatibility of medical implants. A key issue in biocompatibility research is platelet activation and aggregation on the biomaterials' surface. Stoichiometric and nonstoichiometric titanium nitride (TiN_x) films were developed by sputtering as case study materials, for probing platelet activation behavior onto them. Atomic force microscopy (AFM) facilitates the real-time studies of cells and guarantees cellular viability. In this work a methodology for platelets study by AFM was developed. The morphological, structural, optical, and wettability properties of the TiN_x films were obtained by AFM, x-ray diffraction, spectroscopic ellipsometry, and contact angle measurements.The properties of TiN_x films were correlated with their thrombogenicity involving platelets' adhesion, activation and protein clustering mechanisms. It was found that the TiN_x films stoichiometry and surface roughness affect the platelet response. The stoichiometric and smoother TiN films promote platelets adhesion and activation.

Key words: Platelets, Titanium nitride, Atomic force microscopy, Spectroscopic ellipsometry, Wettability