Evaluation of bone formation on ultra-fine structures in simulated body fluid

Abstract Surface modifications are commonly utilized to adjust the properties of titanium and its alloy surface to the specific needs of medical applications, but there are disadvantages such as poor osteoconductive properties and low adhesion of bone cells to the implant surface. To overcome these limitations, the surface properties affecting osseointegration during implantation must be altered. In this study, we applied a new method for improving surface modifications based on the characteristics of an electrolytic solution. In electrolyte solution containing NaF in Na2SO4, uniform TiO2 nanopores formed and HAp nanoparticles were electrodeposited around the TiO2 nanopores. In the electrolyte solution containing NH4F in (NH4)H2PO4, coarse protrusions, including HAp nanoparticles, were regularly deposited onto the TiO2 barrier layer. The surface characteristics and distributed elements were investigated by energy-dispersive X-ray spectroscopy analysis, while analysis of the ultra-fine structure of the surface was carried out by field emission scanning electron microscopy. To investigate the behavior of the anion, chemical states were analyzed by X-ray photoelectron spectroscopy. The narrow spectra for Ti 2P, Ca 2p, and P 2p were similar and depended on the characteristics of the electrolyte solution. In addition, the Ca 2p spectrum showed two peaks for Ca 2p3/2 and 2p1/2 at 347.4 and 351.3 eV, respectively, which may be related to hydroxyapatite. Additionally, the P peak was deconvoluted into two peaks for P1/2 and P3/2 levels with binding energies of 134.2 and 133.4 eV, respectively. A soaking test showed that apatite morphologies were well-formed onto the modified surface at different times.