Electrophoretic deposition of hydroxyapatite and hydroxyapatite-alginate on rapid prototyped 3D Ti6Al4V scaffolds

The advantage of using bioceramic particles coated on porous three-dimensional structures is still unexplored in the purpose of improving the osteoinduction of hybrid metallic scaffold implants in vivo. In this study, we evaluate electrophoretic deposition (EPD) to coat porous Ti6Al4V scaffolds with hydroxyapatite (HA). Scaffolds were shaped in different open structures with a horizontal shift in fiber stacking. They were produced using three-dimensional fiber deposition method and were coated by EPD with HA powder (d (10) = 1.7, d (50) = 5.7 and d (90) = 18 A mu m) suspended in ethanol or butanol at different concentration, DC voltage, and time. A composite HA-alginate was also used to coat the scaffolds. Alginate was used as a binder, and the coating properties (homogeneity, thickness, cracks, continuity, etc.) were compared to coatings obtained from pure HA suspensions. Voltage and time of deposition effects were studied between 10 and 140 V and 10 and 120 s, respectively. Coating thickness and density with respect to the depth of the porous structure were studied by observing cross sections using scanning electron microscopy and image processing analysis. HA-alginate combination resulted in a homogeneous and deeper dense layer of HA. This work also points to the characteristics of HA-alginate composite as a superior alternative to pure HA coating which needs an appropriate thermal treatment for adequate substrate adhesion.