Key Engineering Materials Vols. 330-332

Abstract: Film-coating on the surface of titanium was investigated by hydrothermal treatments with a maximal pressure of 6.3 MPa (280°C) in CaO solution and water to improve bioactivity and biocompatibility. As a result, calcium titanate (CaTiO3) film was formed on the titanium surface. The surface-coated titanium was immersed in a simulated body fluid (SBF) to estimate its bioactivity. Apatite precipitation was observed on all hydrothermal-treated titanium surfaces after immersion in SBF for 4 weeks. In particular, the apatite precipitation of titanium treated with 6.3 MPa in CaO solution was clearer and larger in amount than those of all other hydrothermal-treated specimens. The results suggest that surface modification of titanium with high-pressure hydrothermal treatments can be expected to improve bioactivity and biocompatibility.

Abstract: Collagenous molecule was successfully immobilized to hydroxyapatite (HA) surface through a molecular bridge (2-Hydroxyethyl acrylate, HEMA) that was grafted to the surface with covalent bond by gamma irradiation. Hydroxyapatite modified by atelocollagen had been characterized by several surface sensitive techniques, such as FT-IR, SEM, XPS. The investigations showed that the collagen, a bioactive macromolecule, was immobilized on the HA surface through covalent bond.

Abstract: In this work, nano-TiO2 powders were deposited onto Ti-6Al-4V substrates to produce coating using plasma spraying. The TiO2 coatings were respectively by acid, alkali and heat treatment to produce the bioactive surface. The bioactivity of TiO2 coating was examined by simulated body fluids test. The results obtained indicated apatite was formed on the surfaces of nano-TiO2 coatings treated by H2SO4, HCl and HF solutions, while it could not be formed on the surface of the nano-TiO2 coating treated by NaOH solution at low concentration. After alkali attack and heat treatment at 600°C, the bioactivity of nano-TiO2 coating disappeared.

Abstract: Cerium oxide films have been fabricated using dual plasma deposition. X-ray diffraction. (XRD) reveals a crystalline phase and X-ray photoelectron spectroscopy (XPS) shows that La exists predominantly in the +4 oxidation state. The activated partial thromboplastin time is longer than that of blood plasma and stainless steel. Furthermore, the numbers of adhered, aggregated and morphologically changed platelets are reduced compared to low-temperature isotropic carbon (LTIC). HUVEC cells exhibit good adhesion and proliferation behavior on cerium oxide films. This study suggests rare earth oxide films are potential blood-contacting biomedical materials.

Abstract: The surface of alumina discs (γ phase) was modified by the reaction between the Al-OH groups on the surface of alumina and oxalic acid, resulting in carboxylatoaluminoxanes. The alumina discs with modified surface were soaked in SBF for 6 hours, promoting an intense precipitation of calcium phosphate. The formation of evenly distributed calcium phosphate crystals controlled by the alumina surface, achieved in this work, has the potential to significantly modify the bioinert behavior presented by this material.

Abstract: Bone-like apatite coatings were prepared using a biomimetic method in a simulated body fluid (SBF). The effect of initial pH values on the surface morphology of biomimetic apatite coating was studied. The coatings were characterized using X-ray diffraction and environmental scanning electron microscope. It was revealed that the morphology of the biomimetic apatite coating could be tailored by manipulating the initial pH of the SBF solution.

Abstract: Amorphous Ta-O films were synthesized by reactive pulse unbalanced magnetron sputtering system in this paper. Then the well-crystallized Ta-O films were obtained after they were annealed in vacuum at 800°C for 1h. Hydroxyl group on the surface of amorphous tantalum oxide films was prepared by plasma hydrogenation method. The phase structure was investigated by X-ray diffraction (XRD). The hydroxyl group was characterized using Fourier transform infrared spectroscopy (FTIR). The morphology and growth behavior of the vitro platelet adhesion on the as-deposited, annealed and plasma hydrogenated Ta-O films were analyzed through scanning electron microscope (SEM). The results showed that the quantity of platelet adhered onto the annealed surface were less than as-deposited and hydrogenised films. A new method of preparing hydroxyl group without coupling agents on the inorganic biomaterials has been studied by plasma hydrogenation.

Abstract: It is known that the organic molecules can provide effective means to tailor the surface properties of the biodegradable ceramic. In this paper, a long-chain organic silane- Octadecyltrichlorosilane(OTS) was used as coupling agent and hydroxyapatite(HA) was the candidate ceramic. Samples were characterized by means of XPS technique. XPS results indicated that Si-O-P bond was formed on the HA surface after surface-modification, which means OTS was grafted onto the HA surface through covalent bond , XPS results also showed that by regulating the surface-modification process Si(Atomic percentage) content on HA surface could be changed from 0 to 2.88%.

Abstract: Bone-Like Microstructured β-TCP/Collagen Layer on Fluoridated Hydroxyapatite Coating, which could able to create a biodegradation layer with enhancing bone formation, was prepared in wet synthesis. The formation of the layer was characterized and discussed.

Abstract: Apatite-forming ability on a zirconia surface was investigated using a conventional SBF (c-SBF), a 1.4 SBF (concentration of ions 1.4 times higher than in SBF) and a supersaturated Ca/P solution. After 5 days a small amount of hydroxyapatite was formed on the zirconia surface in the 1.4 SBF, whereas no apatite was detected on the zirconia surface exposed to the c-SBF for 5 days. In the supersaturated Ca/P solution some isolated clusters of hydroxyapatite were observed on the zirconia surface after only 2 hours, and after 27 hours of immersion time, the zirconia surface was homogeneously covered with hydroxyapatite. Some of the covered zirconia substrates were heat treated at 1050°C for 1 hour. The thermally treated and untreated samples were immersed in SBF for 7 and 14 days. The results confirmed that additional hydroxyapatite was formed in the SBF in both cases, regardless of whether the covered zirconia substrate was pre-heated or not.