Development of novel bone-like nanocomposite coating of hydroxyapatite/collagen on titanium by modified electrophoretic deposition.

Electrophoretic deposition (EPD) is a simple, rapid, and inexpensive technique to accomplish uniform coatings with controlled thicknesses. The EPD using binders that do not require a thermal degreasing process, which also eliminates the polymer components of the composite, are required for coating polymer-ceramic composites. This study demonstrated the application of a modified EPD technique utilizing Mg2+ ions to coat a bone-like hydroxyapatite/collagen nanocomposite (HAp/Col) on a titanium (Ti) substrate. The coating thickness was successfully controlled by varying the applied voltage and/or the treatment time. The adhesive strength of the modified EPD coating, evaluated by the tape test, showed class 0 (coating was not peeled off) and drastically increased in comparison to that of the non-Mg2+ EPD coating, class 5 (coating was completely peeled off). The MG63 cells on the HAp/Col-coated Ti demonstrated similar proliferation to and superior alkaline phosphatase activity to that on the bare Ti. Thus, the HAp/Col-coated Ti is expected to facilitate the surrounding bone formation than the bare-Ti. The results of the study indicated the HAp/Col-coated Ti prepared by the modified EPD is effective for applications in novel instruments, such as, subperiosteal temporary anchorage devices, which strongly requires rapid osseointegration at the bone-implant surface.