Control of surface potential and hydroxyapatite formation on TiO2 scales containing nitrogen-related defects

Hashimoto, Masami; Ogawa, T.; Kitaoka, Satoshi; Muto, Shunsuke; Furuya, Maiko; Kanetaka, Hiroyasu; Abe, Masayuki; Yamashita, Hayato

doi:10.1016/j.actamat.2018.05.072

Cited by 12 publications

(6 citation statements)

References 36 publications

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“…The zeta potential rose and then fell within 1 day, or vice versa, for all samples. This is considered to be due to the adsorption of Ca 2+ and HPO 25 In this case, apatite coverage in SBF exceeded 50% when the zeta potential on the Ti surface was 10-20 mV or −30 to −25 mV. The titania used in this study also exhibited this tendency.…”

Section: Discussionmentioning

confidence: 63%

“…The initial zeta potentials of the anatase and rutile that formed apatite had absolute values of approximately 25-35 mV. Hashimoto et al investigated apatite formation on Ti heated under various conditions in N 2 -O 2 mixed gas with an O 2 partial pressure of 10 −14 Pa 25. In this case, apatite coverage in SBF exceeded 50% when the zeta potential on the Ti surface was 10-20 mV or −30 to −25 mV.…”

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confidence: 99%

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Relationship between valence of titania and apatite mineralization behavior in simulated body environment

Miyazaki

Akaike

2021

J. Am. Ceram. Soc.

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Titania-based materials are attractive for hard tissue repair due to their bone-bonding ability induced by apatite formation in the body environment. Various surface treatments have therefore been developed to produce a hydrated titania layer on Ti and its alloys. Titania takes various valences, such as TiO (Ti 2+ ) and Ti 2 O 3 (Ti 3+ ), as well as typical TiO 2 (Ti 4+ ); however, there is no comprehensive study of structural effects on the apatite-forming ability of these titanias. In this study, we investigated apatite formation on titania powders with various valences in simulated body fluid. Anataseand rutile-type TiO 2 formed apatite in simulated body fluid within 7 days, but TiO and Ti 2 O 3 did not. In contrast, when the titania powders were treated with NaOH solution, the surface converted to tetravalent titania and all samples formed apatite.It is proposed that the surface electrical states of TiO and Ti 2 O 3 are strongly affected by their bulk conductivity and that these behaved like pure Ti metal, which has poor apatite-forming ability. Apatite formation was favorable when the titania had a high absolute value and exhibited high fluctuations of zeta potential during initial stages in simulated body fluid, owing to adsorption of large amounts of Ca 2+ and HPO 4 2− . K E Y W O R D Sapatite, bioactivity, calcium phosphate, titanium oxide | MATERIALS AND METHODS | SpecimensDivalent TiO, trivalent Ti 2 O 3 (Kojundo Chemical Lab. Co., Ltd., Japan), tetravalent anatase-type TiO 2 (MC-50, average primary particle size: 24 nm; Ishihara Sangyo Kaisha Ltd., Japan, and FUJIFILM Wako Pure Chemical Co., Japan), and rutile-type TiO 2 (FUJIFILM Wako Pure Chemical Co.) were used. The particle sizes of TiO and Ti 2 O 3 were relatively large (around 1-5 mm), so these reagents were ground in a mortar for 7 minutes prior to use.

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Section: Discussionmentioning

confidence: 63%

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confidence: 99%

Relationship between valence of titania and apatite mineralization behavior in simulated body environment

Miyazaki

Akaike

2021

J. Am. Ceram. Soc.

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“…The surface potential is also an important factor that governs the apatite-forming ability. Hashimoto et al [28] investigated apatite formation on Ti metal heat treated in various atmospheres, and they found that a highly negatively (−30 to −15 mV) or positively (10-15 mV) charged sample tended to form a large amount of apatite. In contrast, the Ti-Hf alloy formed with hafnium titanate with a highly Fig.…”

Section: Discussionmentioning

confidence: 99%

Compositional dependence of the apatite formation ability of Ti–Zr alloys designed for hard tissue reconstruction

Miyazaki

Hosokawa

Yokoyama

et al. 2020

J Mater Sci: Mater Med

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Ti-Zr alloys are expected to be novel biomaterials with low stress shielding owing to their lower Young's moduli than pure Ti. The drawback of metallic biomaterials is that their bone-bonding abilities are relatively low. NaOH and heat treatments have been performed to provide Ti-50Zr with apatite-forming ability in the body environment, which is essential for bone bonding. However, the systematic compositional dependence of apatite formation has not been revealed. In the present study, NaOH treatment of Ti-Zr alloys with various compositions and bone-bonding abilities was assessed in vitro by apatite formation in simulated body fluid (SBF). The corrosion current density in NaOH aqueous solution and the amount of Na incorporated into the surface tended to decrease with increasing Zr content. The apatite-forming ability of the treated alloy significantly decreased when the Zr content was ≥60 atom%. This phenomenon is attributed to the (1) low OH content on the surface, (2) low Na incorporation into the treated alloy surface, which enhances apatite formation, and (3) low ability of P adsorption to the Ti-Zr alloy in SBF following Ca adsorption to trigger apatite nucleation. Although the adhesion of the titanate/zirconate layer formed on the surfaces to the substrates increased as Zr content increased, the adhesion between the apatite and the substrate was still low.

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“…Our previous study confirmed that the zeta potential of the N TiO 2 surface formed at 873 and 973 K after 1 h was highly negative (¹27 mV) and positive (+20 mV), respectively. 13), 14) The zeta potential of Ti cannot be measured due to its conductivity and thus the surface potential of untreated Ti measured by kelvin probe force microscopy was zero. 14) The surfaces of negatively-and positively-charged N TiO 2 and untreated Ti were observed using a scanning electron microscope (SEM) (SU-8000, Hitachi, Co. Ltd. Tokyo, Japan) and their surface roughness and contact angle were measured using a laser microscope (OPTELICS HYBRID mc200, Lasertec, Yokohama, Japan) and contact angle meter (DM-701, Kyowa Interface Science Co., Ltd., Saitama, Japan), respectively.…”

Section: Experimental Procedures 21 Preparation and Characterizationmentioning

confidence: 99%

Enhancement of cell differentiation on a surface potential-controlled nitrogen-doped TiO<sub>2</sub> surface

Hashimoto

Kitaoka

Furuya

et al. 2019

J. Ceram. Soc. Japan

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MC3T3-E1 cell differentiation is more pronounced after 14 days incubation on charged nitrogen-doped TiO 2 surfaces compared to on an untreated, neutral Ti surface. The protein fibronectin (Fn) was detected by an immunogold-labeling technique and Ca and P were detected by time-of-flight secondary ion mass spectrometry. Both techniques revealed that an adhesive protein such as Fn adsorbs equally on negatively-charged, positivelycharged, and untreated Ti surfaces in culture medium. However, the adsorption of Ca and P was only detected on charged nitrogen-doped TiO 2 surfaces. The enhanced adsorption of inorganic ions and Fn is probably responsible for promoting initial stage of osteoblast differentiation. The conformation of adsorbed Fn was observed by high-speed atomic force microscopy and found to be in the side-on orientation on the positivelycharged surface. This finding may help elucidate the relation between Fn conformation and cell activity on surface potential-controlled nitrogen-doped TiO 2 surfaces in future.

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Control of surface potential and hydroxyapatite formation on TiO2 scales containing nitrogen-related defects

Cited by 12 publications

References 36 publications

Relationship between valence of titania and apatite mineralization behavior in simulated body environment

Relationship between valence of titania and apatite mineralization behavior in simulated body environment

Compositional dependence of the apatite formation ability of Ti–Zr alloys designed for hard tissue reconstruction

Enhancement of cell differentiation on a surface potential-controlled nitrogen-doped TiO<sub>2</sub> surface

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