Characterization of electrolytically prepared brushite and hydroxyapatite coatings on orthopedic alloys

Abstract

Details of a procedure for electrolytically preparing highly pure brushite (CaHPO, . 2H,O) coatings on high surface area metal substrates are provided. The influence of current density and deposition time on coating morphology is described. After a discussion of procedures used to convert the brushite coatings to hydroxyapatite, results from a preliminary animal study that demonstrate the propensity of these coatings to stimulate bony ingrowth into porous plugs are presented.

Hydroxyapatite coating by electrophoretic deposition at dynamic voltage

“…Among these methods, EPD is a fairly rapid and inexpensive way of producing a dense and uniform coating on substrates even with complex geometries. EPD is an old but effective technique for depositing on an electrode charge-carrying particles from a stable colloidal suspension, when under the influence of an applied direct current [22][23][24][25][26][27] . This method comprises two steps: the migration of charged particles in a liquid solvent by the action of an applied electric field (electrophoresis), and the coagulation of particles to form an adherent layer on the electrode (deposition).…”

Influence of Temperature and Time For Direct Hydroxyapatite Electrodeposition on Superhydrophilic Vertically Aligned Carbon Nanotube Films

“…Nevertheless, the preference of a direct growth mechanism can be inferred from several observations (P H , ions concentration, temperature and environment). Three hypothesis about HA electrodeposition process were proposed by other authors [33][34][35][36]. The first one is that no charge evolution has been reported for HA particles in basic media [16], which exclude electrostatic forces as responsible for a hypothetical indirect deposition.…”

Preventing infection of osseointegrated transcutaneous implants: Incorporation of silver into preconditioned fibronectin-functionalized hydroxyapatite coatings suppresses Staphylococcus aureus colonization while promoting viable fibroblast growth in vitro

“…Higher current densities are associated with more vigorous hydrogen evolution and the overall process is less efficient as a larger proportion of brushite crystals are unable to survive the turbulent environment of a high current density and are thus lost. 37 Redepenning et al reported that the crystals that do survive this environment would be expected to adhere better, resulting in coatings with an overall greater integrity. 37 The same current density and time was used to produce HA coatings, which were not as rough as HAAg100, indicating that the silver content affects the topography of these surfaces.…”

“…37 Redepenning et al reported that the crystals that do survive this environment would be expected to adhere better, resulting in coatings with an overall greater integrity. 37 The same current density and time was used to produce HA coatings, which were not as rough as HAAg100, indicating that the silver content affects the topography of these surfaces. Previous x-ray diffraction analysis of HAAg showed peaks that were sharper than those observed for HA, suggesting that the Ag þ ion incorporation may increase the crystallinity.…”