title: Influence of albumin on the tribological behavior of Ag-Ti (C, N) thin films for orthopedic implants.
abstract: With the increase of elderly population and the health problems arising nowadays, such as cancer, knee and hip joint prostheses are widely used worldwide. It is estimated that 20% of hip replacement surgeries simply fail after 5years, due to wear loosening, instability and infection. In this paper it is reported the study of advanced materials with the ability to overcome some of these drawbacks. The development of ceramic coatings, based on carbonitrides of transition metals, such as TiCN, doped with silver, Ag, may represent an effective solution. Thin films of Ag-TiCN were produced by dc reactive magnetron sputtering with silver contents ranging from 4 to 8at.%. The physical, chemical, structural, morphological/topographical, mechanical and tribological properties were evaluated. The tribological tests were performed in a unidirectional wear simulator, pin on disk, being the antagonists of a ceramic Al2O3 ball, and using simulate body fluids as lubricant. Hank's Balanced Salt Solution (HBSS) and bovine serum albumin (BSA) in HBSS were chosen, in order to evaluate the lubrication ability of the solution containing the protein, albumin. The results revealed that the coatings with Ag content ranging from 4 to 8at.%, were the most promising, as the tribological properties were superior to the results reported by other authors, which also developed Ag-TiCN coatings containing similar Ag contents and using similar test conditions. The presence of albumin leads to a lower wear in all the test conditions, and this enhancement was higher in the hydrophobic surfaces.
authors.affiliation: Universidade do Minho, Departamento de Física, Campus de Azurém, 4800-058 Guimarães, Portugal. Electronic address: alves.cristiana89@gmail.com.
authors.forename: C F Almeida
authors.initials: CF
authors.lastname: Alves
authors.forename: F
authors.initials: F
authors.lastname: Oliveira
authors.forename: I
authors.initials: I
authors.lastname: Carvalho
authors.forename: A P
authors.initials: AP
authors.lastname: Piedade
authors.forename: S
authors.initials: S
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D002417:Cattle; D020099:Coated Materials, Biocompatible / Q000494:pharmacology; D055119:Elastic Modulus / Q000187:drug effects; D008153:Lubrication; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D009985:Orthopedics; D056951:Photoelectron Spectroscopy; D019736:Prostheses and Implants; D012710:Serum Albumin, Bovine / Q000494:pharmacology*; D012834:Silver / Q000494:pharmacology*; D013059:Spectrum Analysis, Raman; D013500:Surface Tension / Q000187:drug effects; D014025:Titanium / Q000494:pharmacology*; D014961:X-Ray Diffraction
chemical_list: D020099:Coated Materials, Biocompatible; D012710:Serum Albumin, Bovine; D012834:Silver; D014025:Titanium
keywords: Critical wetting tension; Hydrophobic surface; Lubrication limit; Nanostructured coatings; XPS