Adsorption of human plasma proteins to modified titanium surfaces.
OBJECTIVE
The aim of this study was to examine the effect of modified titanium (Ti) surfaces on the initial events of plasma proteins adsorption.


METHODS
'Ti disks' with three types of surface modifications were compared: machined, acid-etched and acid-etched and blasted. Physical and chemical characterizations of the surfaces were performed via scanning electron microscopy (SEM), atomic force microscopy (AFM) used for analysis of surface topography, characterization of the titanium oxide (TiO2) layer was carried out by X-ray photoelectron spectroscopy (XPS) and characterization of surface energy by the determination of contact angles. Evaluation of plasma proteins' adsorption to the treated Ti surfaces was performed by mass spectrometry, confocal laser scanning microscopy and XPS. Quantitative proteins' assessment was carried out by enzyme-linked immunosorbent assay.


RESULTS
SEM images revealed major differences in the topography of the examined surfaces. Acid-etched and blasted Ti surfaces were found to have higher roughness values and a thicker TiO2 layer as compared with acid-etched and machined surfaces. Moreover, acid-etched and blasted surfaces showed high surface area differentiation, pointing to a high increase in the three-dimensional (3D) surface area over the 2D surface area compared with the other surfaces. Adsorption of plasma proteins to the acid-etched and blasted Ti surfaces was both qualitatively and quantitatively more intense compared with the machined and acid-etched surfaces. This was shown for each examined protein, total proteins and by the removal degree of the protein coat.


CONCLUSIONS
The preferential adsorption of plasma proteins to the acid-etched and blasted Ti surfaces may be explained by its topographical characteristics and by the increase of the 3D surface area of this modified surface.
Sela
Michael N
MN
Oral Microbiology and Ecology Lab, The Faculty of Dental Medicine, The Hebrew University, Jerusalem, Israel. msela@cc.huji.ac.il
Badihi
Liad
L
Rosen
Graciela
G
Steinberg
Doron
D
Kohavi
David
D
D000134:Acid Etching, Dental; D000327:Adsorption; D000497:Alloys; D001672:Biocompatible Materials / Q000737:chemistry; D001798:Blood Proteins / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry*; D045662:Dental Etching; D004577:Electron Probe Microanalysis; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D013058:Mass Spectrometry; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D017155:Wettability
D000497:Alloys; D001672:Biocompatible Materials; D001798:Blood Proteins; D020099:Coated Materials, Biocompatible; D003722:Dental Alloys; C031462:titanium alloy (TiAl6V4); C009495:titanium dioxide; D014025:Titanium