The bioactivity of PDMS-CaO-SiO₂ based hybrid materials prepared by the addition of transition metal alkoxides

The bioactivity of organic inorganic hybrid materials derived from polydimethylsiloxane, tetraethoxysilane, calcium nitrate tetrahydrate and a different amount of pentaethoxy-niobium/tantalum was examined. We investigated the relationship between the hydroxyapatite depositions on the hybrid's surface in a simulated body fluid (KOKUBO solution) and the molecular structure oh hybrids. The in vitro formation of hydroxyapatite was characterized by using a simulated body fluid and the molecular structure of the hybrid was characterized by fourier transformed infrared and silicon 29 solid-state magic angle spinning nuclear magnetic resonance. The addition of a different amount of transition metal alkoxides lead to a different amount of silanol in the obtained hybrid materials. Additionally, the releasing ability of calcium from hybrid into simulated body fluid was different among the obtained hybrid materials, corresponding to the amount of transition metal. The hybrid material with a ratio of 0/1 and 1/0=Nb/Ta, polydimethylsiloxane/tetraethoxysilane=0.1/1 and 0.1=(Ta+Nb)/tetraethoxysilane showed the higher apatite formation ability.