Evaluation of the Cathodic Electrodeposition Effectiveness of the Hydroxyapatite Layer Used in Surface Modification of Ti6Al4V-Based Biomaterials

Abstract

The important issue associated with the design and the fabrication of the titanium and titanium alloy implants is the increase of their biointegration with bone tissue. In the presented paper, the research results concerning the conditions used in the cathodic deposition of hydroxyapatite on the surface Ti6Al4V substrates primarily modified by the production of TiO2 nanoporous coatings, TiO2 nanofibers, and titanate coatings, are discussed. Despite excellent biocompatibility with natural bone tissue of materials based on hydroxyapatite (HA), their poor adhesion to the substrate caused the limited use in the implants’ construction. In our works, we have focused on the comparison of the structure, physicochemical, and mechanical properties of coating systems produced at different conditions. For this purpose, scanning electron microscopy images, chemical composition, X-ray diffraction patterns, infrared spectroscopy, wettability, and mechanical properties are analyzed. Our investigations proved that the intermediate titanium oxide coatings presence significantly increases the adhesion between the hydroxyapatite layer and the Ti6Al4V substrate, thus solving the temporary delamination problems of the HA layer.

TiO2/HA and Titanate/HA Double-Layer Coatings on Ti6Al4V Surface and Their Influence on In Vitro Cell Growth and Osteogenic Potential

“…The main direction in which our research tends is the production of a highly biocompatible system with mechanical properties like cortical bone, which can be applied to the design and fabrication of implants. In the course of previous work, we proved that the morphology and structure of interlayers (ILs) have a significant impact on the morphology and mechanical properties of the deposited hydroxyapatite (HA) layers [30]. In this paper, we show that differences in biological activity also depend on the type of Ti6Al4V/IL/HA systems.…”

“…The hydroxyapatite coating was deposited onto the Ti6Al4V/IL system in the next stage. The synthesis, structural and morphological characterization, as well as the physicochemical and mechanical properties of the TiO 2 /HA and titanate/HA double layers have been previously reported [30]. T5, T-S, and TNF6C materials were cut into pieces 6 mm × 100 mm and 10 × 60 mm and 0.2 mm thick.…”

“…In addition, it is important to ensure that its production process is reproducible for different batches of devices and that the material does not undergo changes in shape or properties during its sterilization process [15][16][17][18][19][20][21]. For this reason, various innovative technologies (e.g., plasma treatment, low-intensity pulsed ultrasound, magnetic field stimulation, anodization, chemical treatment) [22][23][24][25][26][27][28][29], modifications (e.g., incorporation/deposition of various metal ions) [28,[30][31][32][33][34] for the fabrication of biomaterials are being applied to prevent unwanted complications.…”

“…The mechanical parameters (i.e., hardness, Young's modulus) obtained for the hydroxyapatite layer were similar to cortical bone. Furthermore, the adhesion strength between the titanium alloy substrate and the hydroxyapatite layer was significantly increased by the use of intermediate coatings [30]. Nevertheless, the produced materials with a hydroxyapatite layer should also show high biocompatibility and biointegration properties.…”

There Are over 60 Ways to Produce Biocompatible Calcium Orthophosphate (CaPO4) Deposits on Various Substrates

“…TiO 2 [938,939] and TiN [272] have also been used as base layers for RF magnetron sputtering. Similarly, the formation of interlayers of hydrated titanium dioxide on Ti [365,372,477,940] and polar hydrophilic groups on polymers [54,56,63,[73][74][75][76] is essential to improve the adhesion of wet-deposited CaPO 4 . Namely, pretreatment of polyethylene terephthalate, polymethyl methacrylate and polyamide 6 polymer surfaces with NaOH increased the adhesion strength of the deposited apatite from 3.5 to 8.6 MPa, 1.1 to 3.4 MPa and 0.6 to 5.3 MPa, respectively [54].…”