Improved Bonding Strength of Hydroxyapatite on Titanium Dioxide Nanotube Arrays following Alkaline Pretreatment for Orthopedic Implants

Hydroxyapatite (HA) is a bioactive bone substitute used in biomedical applications. One approach to use HA for bone implant application is to coat it on titanium (Ti) implant. However, adhesion of HA on Ti is major concern for their long-term use in orthopedic implants. To enhance the adhesion strength of HA coating on titanium (Ti), the surface of the Ti was anodized and alkaline pretreated prior to coating on Ti by electrodeposition. Alkaline pretreatment of titanium dioxide nanotubes (ATi) accelerated the formation of HA, which mimicked the features and structure of natural bone tissue. Nanostructured HA formed on the ATi and pretreated ATi (P-ATi), unlike on conventional Ti. This study is the first to show that the bonding of HA coating to a P-ATi substrate was stronger than those of HA coating to Ti and to ATi. The preosteoblast response tests were also conducted. The results indicated that HA coating improved preosteoblast proliferation after 3 days in standard cell culture.