Production of tubular porous hydroxyapatite using electrophoretic deposition

Abstract

Hydroxyapatite (HA) ceramics have been recognized as bone substitute materials in orthopedic and dental applications because of their chemical and biological similarity to human bone. Porous HA ceramics can be used as scaffold materials, if their microstructure is controlled in terms of pore size and porosity. The objective of the present work was to produce tubular-shaped HA scaffolds for biomedical applications using the cost-effective technique of electrophoretic deposition (EPD) which enables various 3D shapes to be produced. Nano HA powders were produced and mixed with multi-walled carbon nanotubes (MWCNTs) by a hydrothermal process. Calcium acetate (Ca(CH 3 COO) 2 ), and phosphoric acid (H 3 PO 4 ) were used as starting materials for the synthesis of the nano HA powders. Porous HA coatings were deposited on carbon rods by EPD at 60 V using a butanol suspension mixture containing nano HA powders and MWCNTs. Nano composite coatings produced were sintered at 1200°C for 60 min to burn-out the carbon rod and MWCNTs. It was shown that MWCNTs provided crack-free coating layers after coating and a porous structure after sintering. The porous HA coatings obtained were coated using different EPD parameters in terms of applied voltage and deposition time. EPD provides a coating thickness of ³310¯m for a deposition time of 480 s. This method enabled the formation of coatings with variable thickness, depending on the duration of coating and applied DC voltage. Hydrothermal mixing of HA/MWCNTs and the mechanism of deposition are also discussed. The methods can produce 3D-shaped HA scaffolds for clinical applications. The results demonstrate that the HA tubes obtained are candidate materials as scaffolds for bone repairing and generation.

Calcium orthophosphate deposits: Preparation, properties and biomedical applications

“…Although this is slightly beyond the subject, one should mention that some specific types of CaPO 4 bioceramics might be prepared by EPD [345,346,358,359]. For example, hollow HA fibers of various diameters were fabricated.…”

Calcium Orthophosphate-Based Bioceramics

“…From the material point of view, the major research topics include nanodimensional and nanocrystalline structures [822,823,824], amorphous compounds [825], organic-inorganic biocomposites and hybrid biomaterials [353], biphasic, triphasic and multiphasic formulations [121], as well as various types of structures, forms and shapes. The latter comprise fibers, whiskers and filaments [241,826,827,828,829,830,831,832,833,834,835,836,837,838,839], macro-, micro- and nano-sized spheres, beads and granules [839,840,841,842,843,844,845,846,847,848,849,850,851,852,853,854,855,856], micro- and nano-sized tubes [857,858,859,860], porous 3D scaffolds made of ACP [481,653,861], TCP [86,89,161,528,529,862], HA [167,455,456,498,530,531,532…”

The Effect of Pores in Dual Nano Hydroxyapatite Coating on Thermally Oxidized Commercial Pure Titanium : Mechanical and Histological Evaluation

“…The oxide film average thickness is 1.6µ, measured by microprocess coating thickness gauge, and this disagree withJain et al and Kumar et al (10,11) ,who reported the formation of thicker oxide layer may be due to different thermal oxidation conditions.The surface morphology, oxide grains size and the evolution of surface topography of the oxide film may suggest the mechanism of the growth mode for the oxide barrier which involves the formation of a thin oxide scale followed by its agglomeration and growth, to completely cover the surface, versus oxide film formation mode according to which the nucleation of oxide takes place throughout the surface when it immediately comes in contact with oxygen (11).…”

“…1. Substrate Thermal Oxidization: Mirror polished Cp Ti substrates were ultrasonicated in water bath for 30 min, followed by acetone wash (10) then were heated at 650⁰C for 8h in oven (11) .…”