Papers by Author: Kanji Tsuru

Abstract: Rutile films were deposited on polyethylene terephatalate (PET), polytetrafluoroethylene (PTFE), Silicone, poly6-caprolactam (Nylon6), polyhexamethylene adipamide (Nylon6,6) and Nylon fiber substrates using 0.03 M TiOSO4 and 0.03 M H2O2 aqueous solution at 80°C for 24 h. The rutile films exhibited excellent in vitro bioactivity as they induced apatite deposition in a simulated body fluid (SBF).

Abstract: Titania films were coated by means of sol-gel method on various substrates such as titanium, titanium alloy, silicon wafer, stainless-steel, alumina, and glass slide where they coded as C5Ti, C5Ti6Al4V, C5Si, C5SUS, C5Al2O3 and C5GS, respectively. Their in vitro apatite-forming ability was examined with the Kokubo’s simulated body fluid (SBF; pH 7.4, 36.5°C). C5Ti, C5Ti6Al4V and C5Si deposited apatite particles on their surface within 7 days, whereas, C5SUS, C5Al2O3 and C5GS did not. These results implied that the in vitro apatite-forming ability of the titania films indirectly depended on the chemical or physical properties of the substrates.

Abstract: Porous & rubbery organic-inorganic hybrids were synthesized from tetraethoxysilane (TEOS) and polydimethylsiloxane (PDMS) through a sol-gel route using sieved sucrose granules as a porogen. The porous hybrids with a high content of PDMS behaved like polymer sponge. The porosity was over 90% irrespective of the hybrid composition and the pore diameter ranged from 100 to 500 μm. In the three-dimensional cell culture, mammalian cells were well cultured in the porous hybrids. The present results indicate that the hybrids may be a promising scaffold for developing such functional culture methods.

Abstract: Titania layer was fabricated on the titanium substrates with chemical treatment with 20ml or 40ml of hydrogen peroxide solution and subsequent heat treatment at 400°C, coded as CHT20 and CHT40, respectively. CHT20 spontaneously deposited apatite on the surface in a simulated body fluid (SBF), while CHT40 did not. TF-XRD patterns showed that the diffraction intensity of anatase of CHT20 was higher than that of CHT40. It was suggested that the thicker titania layer indicated in vitro apatite forming ability. The cell proliferation of CHT20 and CHT40 were lower than NT and HT. Since the surface of titania layers became hydrophobic after autoclaving, we can suppose that the cell proliferation on CHT20 and CHT40 were lower than NT and HT due to their surface hydrophobicity.

Abstract: The selective protein adsorption property and the local structure around carbonate ions of nanocrystalline hydroxy-carbonate apatite were examined in this study. Considerable change in the selectivity in the adsorption of BSA and β2-MG was observed due to the incorporation of thecarbonate ions in hydroxyapatite lattice. Since the protein adsorption property seems to be related to the surface charge density of hydroxyapatite due to the carbonation, the chemical states of the incorporated carbonate ions were examined by the 31C CP-MAS NMR spectroscopy. At least four peaks assignable to carbonate ions in A-site(OH-) and B-site(PO4 3-) were observed in 13C CP-MAS NMR spectrum. Thus, we must take into consideration that the surface charge distribution and the decrement of polar groups such as OH- groups due to the distribution of carbonate ions in both Aand B-sites of the hydroxyapatite lattice are particularly favorable for β2-MG adsorption rather than for BSA adsorption.

Abstract: Rutile films were deposited on polytetrafluoroethylene (PTFE) substrates using 1.5 M titanium tetrachloride aqueous solution at 60 °C. The rutile films exhibited excellent in vitro bioactivity as they induced apatite deposition in a simulated body fluid (SBF) within 2 days. Chlorine incorporated in the rutile films did not inhibit apatite deposition.

Abstract: Anatase films with various morphologies were formed on Ti surface through different approaches using hydrogen peroxide solutions. A porous anatase surface was found to favor apatite deposition in SBF, or in vitro bioactivity. Thicker films with wider crack gaps also showed enhanced in vitro bioactivity. However, the most predominant effect was the abundance of Ti-OH functional groups incorporated in the anatase films.

Abstract: This work reports the structure of two glass ceramics prepared in the calcium phosphate system, MK5B and MT13B, using 31P MAS-NMR technique. The results obtained showed that the network of MK5B consisted mainly of Q1 and Q2 groups. Besides these two groups, MT13B material also present Q3 units. The Qn groups detected in both glass ceramics seem to be correlated to the crystalline phases present in their microstructure.

Abstract: Organic-inorganic hybrids involving Ti-O bonds were coated on stainless-steel (SUS316L)substrates. Tetraisopropoxide and titanium methacrylate triisopropoxide were employed as the major starting chemicals to provide TiO2-polydimethylsiloxane (PDMS) layers or organotitanium molecular thin layers, respectively. Fourier transform infrared spectra indicated that each layer contained Ti-O bonds in their structure. The obtained hybrid layers had little effects on the blood-clotting times such as active partial thromboplastin time and prothrombin time. In addition, the number of adhered platelet on the TiO2-PDMS layers depended on the composition, while the organotitanium molecular thin layers suppressed fibrinogen adsorption compared with coating-free SUS 316L substrate.