Hybrids consisting of bone-like apatite and biodegradable polymers are attractive materials for bone repair. We have shown that an alginate gel crosslinked covalently with ethylenediamine (EDA) enhances the repair of skin and nerves. In this study, we report a novel method for fabrication of an apatite-alginate nanohybrid using a simulated body fluid (SBF). Alginate was reacted with 3-aminopropyltriethoxysilane (APES), which gives silanol groups after hydrolysis, and/or EDA, by dehydration condensation using water-soluble carbodiimide to form gels. Modification of alginate with APES alone also gave a gel, because the alginate could be crosslinked by dehydration of silanol groups derived from APES. The gels obtained were soaked in a 1 mol/L CaCl2 solution and subsequently soaked in SBF. Apatite was formed on and inside the alginate gels modified with APES, whereas it was not formed on the gels without APES. Modification of alginate with silanol groups induced not only gel formation but also the apatite-forming ability on and inside the alginate gel in SBF. Consequently, a hydroxyapatite-alginate hybrid can be produced by modification of alginate with silanol groups and subsequent soaking in CaCl2 solution and SBF. Such a material is expected to be useful in bone repair.

Modification of organic polymer with silanol groups in combination with calcium salts enables the polymer to show bioactivity, that is, the polymer forms apatite on its surface after exposure to body environment. However, how modification with silanol groups influences ability of apatite formation on the polymer substrate and adhesive strength between polymer and apatite is not yet known. In the present study, polyamide containing carboxyl groups was modified with different amounts of silanol groups, and its apatite-forming ability in 1.5SBF, which contained ion concentrations 1.5 times those of simulated body fluid (SBF), was examined. The rate of apatite formation increased with increasing content of silanol groups in the polyamide films. This may be attributed to enhancement of dipole interactions. A tendency for the adhesive strength of the apatite layer on the polyamide film to be decreased with increasing content of silanol groups was observed. This may be attributed to swelling in 1.5SBF and having a high degree of shrinkage after drying. These findings clearly show that modification of organic polymers with the functional groups induces apatite deposition, and also determines the adhesive strength of the apatite layer to the organic substrates.

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Purpose This study compared Gavi®, an automated system for the equilibration and dehydration steps of vitrification, and a manual vitrification procedure in terms of effects on clinical outcomes. Methods The authors retrospectively compared survival rate, and clinical and perinatal outcomes after vitrified‐thawed single blastocyst transfer between Gavi® (G method) in 398 cases and Cryotop® (C method) in 208 cases. Results With C and G methods, survival rates were 98.6% (208/211) and 99.3% (398/401), total pregnancy rates were 34.3% (72/208) and 33.4% (133/398), and total miscarriage rates were 22.2% (16/72) and 24.8% (33/133), respectively. Among women <35 years old, pregnancy rates were 41.1% (30/73) and 40.5% (62/153) and miscarriage rates were 13.3% (4/30) and 16.1% (10/62) with C and G methods, respectively. Among women ≥35 years old, pregnancy rates were 31.1% (42/135) and 29.0% (71/245) and miscarriage rates were 28.6% (12/42) and 32.4% (23/71) with C and G methods, respectively. C and G methods showed no significant differences in any trials, including gestational age, cesarean section rate, or birthweight (P > .05 each). Conclusions Gavi® showed comparable clinical outcomes to the manual vitrification method and can be considered an alternative vitrification procedure in assisted reproductive technology.