The Influence of Electrolytic Concentration on the Electrochemical Deposition of Calcium Phosphate Coating on a Direct Laser Metal Forming Surface

Abstract

A calcium phosphate (CaP) coating on titanium surface enhances its biocompatibility, thus facilitating osteoconduction and osteoinduction with the inorganic phase of the human bone. Electrochemical deposition has been suggested as an effective means of fabricating CaP coatings on porous surface. The purpose of this study was to develop CaP coatings on a direct laser metal forming implant using electrochemical deposition and to investigate the effect of electrolytic concentration on the coating's morphology and structure by X-ray diffraction, scanning electron microscopy, water contact angle analysis, and Fourier transform infrared spectroscopy. In group 10−2, coatings were rich in dicalcium phosphate, characterized to be thick, layered, and disordered plates. In contrast, in groups 10−3 and 10−4, the relatively thin and well-ordered coatings predominantly consisted of granular hydroxyapatite. Further, the hydrophilicity and cell affinity were improved as electrolytic concentration increased. In particular, the cells cultured in group 10−3 appeared to have spindle morphology with thick pseudopodia on CaP coatings; these spindles and pseudopodia strongly adhered to the rough and porous surface. By analyzing and evaluating the surface properties, we provided further knowledge on the electrolytic concentration effect, which will be critical for improving CaP coated Ti implants in the future.

Effect of Doping Element and Electrolyte’s pH on the Properties of Hydroxyapatite Coatings Obtained by Pulsed Galvanostatic Technique

“…The reagents were purchased from Sigma Aldrich (St. Louis, MO, USA), and were of analytical grade. All electrolytes were prepared with respect to the Ca/P ratio of 1.67 [35,36]. The chemical composition of the electrolyte is shown in Table 1.…”

“…To achieve this goal, different pH values of 4 and 5 were used, since a pH value higher than 4.5 leads to obtaining coatings with high crystallinity [35,36]. Besides this, the concentration of electrolytes used does not allow to modify the electrolyte's pH at values higher than 5.…”

In Vitro Evaluation of Ag- and Sr-Doped Hydroxyapatite Coatings for Medical Applications

“…However, the coatings obtained with a relaxation time (t OFF ) longer than the activation time (t ON ) through the pulse technique present high crystallinity and adhesion. The concentration of the electrolyte is also an important parameter, as the morphology of the coatings depends on it [53], while the pH of the electrolyte influences the electrochemical reactions and, implicitly, the deposition process [54,55]. Considering all of the abovementioned aspects, HAp-based coatings deposited on titanium alloys through the pulse technique can be considered a controlled drug release system in the case of implantrelated infections.…”