ABSTRACT
BACKGROUND: It has been reported that bioactivity is found to be favored by the co-operative behavior of silanol (Si-OH)or Ti-OH etc. groups on the material surface and the involved calcium ions. To confirm the hypothesis that a new family of organic-inorganic hybrid materials, which incorporate gelatin chains covalently into Si-O-Ti network, is synthesized through sol-gel procedure.OBJECTIVE: To synthesize a hybrid of gelatin and CaO-SiO2-TiO2 system which is used for bone repairing, and observe its structure and bioactivity.DESIGN: Randomized control observation.SETTING; the laboratory, School of Material Science and Engineering, Shaanxi University of Science and Technology. MATERIALS: Gelatin (Sinopharm Chemical Reagent Co., Ltd), titanic acid isopropyl ester (Gu'an Hengye Fine Chemicals Co., Ltd), γ-glycidoxy propyl trimethoxy silane (Jingzhou Jianghan Fine Chemicals Co., Ltd), calcium nitrate (Tianjin Bodi Chemicals Co., Ltd)METHODS: The experiment was carried out in the laboratory, School of Materials Sciences and Engineering, Shaanxi University of Science and Technology between April and August in 2006. A new type of bioactive organic-inorganic hybrid was synthesized through sol-gel processing starting from gelatin, γ-(2,3-glycidoxypropyl)trimethoxysilane (GPSM),Tetraisopropyltitanate (TiPT) and calcium nitrate. ①Structure of the hybrid: The structures of the products were investigated with Fourier transformed infrared (FT-IR) diffusive reflection spectroscope, X-ray diffraction (XRD) instrument and scanning electron microscope (SEM) respectively.②Bioactivity: The products Ti15Ca0 and Ti15Ca20 were soaked in a stimulated body fluid (SBF) to evaluate the morphology of the surfaces by SEM and thin-film XRD. MAIN OUTCOME MEASURES: The structure and bioactivity of the hybrid.RESULTS: ①The hybrid was completely amorphous and its surface was almost homogenous, which implied the covalent bonding between the organic component and inorganic component. FT-IR spectra result verified the occurrence of Si-OH group and Si-O-Ti bond, as well as the addition of TiPT supplied Si-O-Ti bond. ②There were lots of apatite crystallines formed on the surface of hybrid Ti15Ca20 after soaked in SBF for 7 days, which confirmed their in vitro bioactivity. These apatite particles were similar to the bioglass and other bioactive materials in the patterns. CONCLUSION: A new type of organic-inorganic hybrid material, which incorporates gelatin chains covalently into Si-O-Ti network, is synthesized through sol-gel procedure. There are lots of apatite and brushite crystals formed on the surface of the product Ti15Ca2O after soaking in SBF for 7 days, which obviously proves the bioactivity of the hybrid.