Biodegradable Ceramics Consisting of Hydroxyapatite for Orthopaedic Implants

Abstract

Abstract:This study aims to analyze hydroxyapatite (HAP) coatings enriched with Mg and Ti prepared by a magnetron sputtering technique on Ti6Al4V substrate. For preparation of the coatings, three magnetron targets (HAP, MgO and TiO 2 ) were simultaneously co-worked. The concentration of Mg added was varied by modifying the power applied to the MgO target. In all coatings, the Ti concentration was maintained constant by keeping the same cathode power fed during the whole deposition. The influence of different Mg dopant contents on the formation of phase, microstructure and morphology of the obtained Ti-doped HAP coatings were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Moreover, the effects of Mg addition upon corrosion, mechanical and biological properties were also investigated. Mg-and Ti-doped HAP coating obtained at low radio-frequency (RF) power fed to the MgO target provided material with high corrosion resistance compared to other coatings and bare alloy. A slight decrease in hardness of the coatings was found after the Mg addition, from 8.8 to 5.7 GPa. Also, the values of elastic modulus were decreased from 87 to 53 GPa, this being an advantage for biomedical applications. The coatings with low Mg concentration proved to have good deformation to yielding and higher plastic properties. Biological test results showed that the novel surfaces exhibited excellent properties for the adhesion and growth of bone cells. Moreover, early adherent vital cell numbers were significantly higher on both coatings compared to Ti6Al4V, suggesting that Mg ions may accelerate initial osteoblast adhesion and proliferation.

Chitosan–Hydroxyapatite Composite Layers Generated in Radio Frequency Magnetron Sputtering Discharge: From Plasma to Structural and Morphological Analysis of Layers

“…Deconvoluted IR bands from 1004/995 cm −1 (in the IR spectra of the HApCs target/coating, Figure 4 c,e) are ascertained to the C-H/C-O bond vibrations in the HApCs [ 32 ]. The IR band from 1107 cm −1 can indicate the P-O vibrations in the non-apatitic phosphate structure [ 34 ].…”

Cationic Substitutions in Hydroxyapatite: Current Status of the Derived Biofunctional Effects and Their In Vitro Interrogation Methods

“…HA coatings were fabricated by sol-gel [137,138], electrophoresis (EPD) [137,139,140], electro-chemical deposition (ECD) [141,142], ion-beam assisted deposition [132,143], micro-arc oxidation [144,145], and biomimetic deposition from supersaturated simulated body media solution [146,147,148]. Emerging synthesis approaches include physical vapour deposition techniques such as: magnetron sputtering [35,67,68,70,131,135,149,150,151], pulsed laser deposition (PLD) [35,89,97,98,105,135], pulsed electron deposition [35,135,152,153,154,155], and matrix-assisted pulsed laser evaporation [117,135,156,157,158,159]. The advantages and limitations of each technique have been reviewed insightfully by Narayanan and Bosco et al [160,161] and Surmenev [131].…”

Hydroxyapatite Surfaces Functionalized with a Self-Assembling Peptide: XPS, RAIRS and NEXAFS Study

“…These cathodes were selected due to the similar deposition rate with that of HAP established after preliminary investigations. Before the depositions, substrates were pretreated as described in References [11,12]. Deposition conditions of the analyzed samples were base pressure = 1.3 × 10 −4 Pa; Ar pressure = 6.6 × 10 −1 Pa; bias voltage = −60 V; and deposition temperature = 700 • C. RF power fed applied on each used cathode is listed in Table 1.…”

“…In previous papers, some of us reported the preparation of HAP coatings, enriched with Mg and either Si or Ti deposited on the Ti6Al4V alloy by RF magnetron sputtering [ 11 , 12 ]. The HAPs incorporating different types of ions were investigated in order to achieve better control over osteoblast adhesion to HAP coatings.…”