Preparation And Biological Evaluation Of Nano-Hydroxyapatite Coating On Titanium Surfaces

Objective:Nano-hydroxypaptite (Nano-HA) is similar to the body HA and has better biological property. Electrochemical deposition technology can prepare nano-HA coatings on porous titanium surfaces. Moreover, this technology does not destroy the porous structures. This study applied a electrochemical technology to prepare a nano-HA coating and evaluated the effects of the nano-HA coating on osteoblast biological ability and osteoporosis implant osseointegration.Methods:Titanium samples were treated sandblasting,HF/HNO3and HC1/H2SO4etching. Nano-HA coating were prepared by using electrochemical technology. Roughened plates were used as the working electrode (cathode) for te deposition of nano-HA, while a platinum (Pt) plate as the counter electrode. The electrolytes were prepared by dissolving reagent-grade Ca(N03)2(0.6mM) and NH4H2PO4(0.36mM) with Ca/P ratio being1.67. Surface analysis was performed by FSEM, XRD, FTIR and surface rough tester (TR240). Experiment1:Murine preosteoblast cells (MC3T3-E1) proliferatin, alkaline phosphatase (ALP) activity, and osteocalcin release on nano-HA coated surfaces were performed. Experiment2:Osteoporosis rats were established by using ovariectomized surgery. Two implants were inserted into both tibiae of rats. After4weeks and12weeks of implantation, tibias were retrieved and prepared for histomorphometric evaluation and removal torque tests (RTQ).Results:Porous and wave topography appeared on control plate surfaces. Rod-like crystals uniformity covered the porous surfaces. But surface morphology of samples was clear. XRD and FTIR analysis showed this coating consisted of HA. Surface roughness of control and test samples were1.185±0.06,1.167±0.096. Significant increase in cell proliferation, total protein, ALP activity, and osteocalcin production (P<0.05) were observed for nano-HA coated surfaces.Animal experiments showed nano-HA coated implants showed a significantly greater BIC, bone area within all threads in osteoporosis rats after4and12weeks (P<.05), and RTQ values after12weeks (P<.05).Conclusions:This study demonstrated that the nano-HA deposited by the electrochemical technology improved osteoblast biological ability and osteoporosis osseointegration.