Hydroxyapatite coating on titanium alloy TNTZ for increasing osseointegration and reducing inflammatory response in vivo on Rattus norvegicus Wistar rats

Abstract Hydroxyapatite (HA) coating has been carried out on a titanium alloy Ti–29Nb–13Ta-4.6Zr (TNTZ) to improve the biocompatibility and bioactivity of the alloy in order to attain a high degree of osseointegration and low inflammatory reactions in bone tissue after implantation in orthopedic implant applications. The coating process was carried out using the electrophoretic deposition (EPD) method. TNTZ implants with and without HA coating were installed in the tibia of the Rattus norvegicus Wistar test rats; the test animals were then terminated after two weeks. The degree of osseointegration was measured using a removal torque tester, the Tumor Necrosis Factor-Alpha (TNF-α) level was measured by using the Enzyme-Linked Immunosorbent Assay (ELISA) method, and a histopathological analysis was carried out on the implanted tissue. TNTZ implants with HA coating exhibit significantly higher osseointegration compared to those without HA coating, whereas TNTZ implants without HA coating can trigger significantly higher TNF-α levels. Greater osteogenesis occurs in a bone tissue fitted with TNTZ implants with HA layers. The HA coating on the surface of the TNTZ implant can reduce excessive inflammation, enhance the osteogenesis process, and then improve osseointegration in the bone tissues of test animals. It is also expected to be suitable for orthopedic implant applications.