Gel-derived SiO2-CaO-Na2O-P2O5 bioactive powders: Synthesis and in vitro bioactivity

Autor(es)

Siqueira, Renato Luiz ^[1] ; Peitl, Oscar ^[1] ; Zanotto, Edgar Dutra ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Mat Engn, Programa Posgrad Ciencia & Engn Mat, Lab Mat Vitreos, BR-13565905 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Materials Science & Engineering C-Materials for Biological Applications; v. 31, n. 5, p. 983-991, JUL 20 2011.
• Citações Web of Science: 58

Resumo

In the present work, bioactive powders of the quaternary SiO(2)-CaO-Na(2)O-P(2)O(5) system were synthesized by means of a sol-gel route. In their synthesis, tetraethoxysilane (Si(OC(2)H(5))(4)), calcium nitrate tetrahydrate (Ca(NO(3))(2)center dot 4H(2)O) and sodium nitrate (NaNO(3)) were chosen as precursors of SiO(2), CaO and Na(2)O, respectively. For P(2)O(5), two different precursors were tested: triethylphosphate (OP(OC(2)H(5))(3)) and phosphoric acid (H(3)PO(4)). The gels were then converted into ceramic powders by heat treatments in the temperature range 700-1000 degrees C. The resulting materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) and in vitro bioactivity in acellular simulated body fluid (SBF). During the conversion of the gels into ceramics the mineralization behavior of the two sets of samples was different, but all the resulting materials were bioactive. The samples prepared using phosphoric acid exhibited the best in vitro bioactivity. This result was attributed to the preferential formation of bioactive sodium calcium silicate Na(2)Ca(2)Si(3)O(9) crystals, especially in the samples submitted to heat treatments at 700 and 800 degrees C, which could not be observed in the samples prepared using triethylphosphate. (C) 2011 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 07/08179-9 - Processos cinéticos em vidros e vitrocerâmicas
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Temático