Navegando por Assunto "Phosphorus precursor"

Agora exibindo 1 - 2 de 2
  • Imagem de Miniatura
    Item
    BG-58S macrospheres produced using BG powder synthesized by alkali-mediated sol–gel process and different phosphorus precursor
    (Springer Nature Link) Grancianinov, Karen Julie Santos; Santos, Kennedy dos; Gonçalves, Isabela; Donda, Giovanni Moreira; Lauda, Diogo Ponte; Amaral, Suelen; Souza, Amanda; Vasconcellos, Luana de; Oliveira, Ivone Regina de
    Purpose Bioactive glass (BG) spheres with uniform shape and specific size variation are allowed to be packed into a 3D arrangement, which results in an open porosity that improves bone growth. Methods BG-58S macrospheres were produced using BG powder synthesized by alkali-mediated sol–gel process and different phosphorus precursors (TEP or phosphoric acid-AF). Macrospheres (MAF-1 M, MAF-2 M, MTEP-1 M, and MTEP-2 M) were characterized as to surface morphology and size, theoretical density, and specific surface area/pore size distribution. In vitro bioactivity was evaluated in simulated body fluid (SBF). In vitro tests were conducted (for MAF-2 M and MTEP-2 M) as cell viability, total protein content, determination of alkaline phosphatase, cell adhesion by means of SEM, and mineralization nodules formation compared to commercial product (BG-45S5). Biological performance was verified through histological and histomorphometric analyses around the samples: BG-45S5, MTEP-2 M, and control (clot). Results All physicochemical characterizations demonstrated favorable macrospheres for application in bone grafting. MTEP-2 M and MAF-2 M showed higher cell viability and total protein content when compared to BG-45S5 with a statisti- cal difference (p < 0.05); however, no statistical difference was detected among the groups regarding the determination of alkaline phosphatase (p > 0.05). Cells adhered to the surface were observed for all samples as well as nodules of minerali- zation. The results referring to in vivo biological assays showed no statistical difference between the experimental groups MTEP-2 M, BV45S5, and clot control in the two periods evaluated (p > 0.05). Conclusion The method used in this study was able to prepare macrosphere bioglass, and this material seems to be a promis- ing biomaterial to improve bone tissue regeneration.
  • Imagem de Miniatura
    Item
    Influence of manufacturing parameters on bioactive glass 45S5: Structural analysis and applications in bone tissue engineering
    (Elsevier) Santos, Kennedy Wallace dos; Costa, Karen Julie Santos Grancianinov; Gonçalves, Isabela dos Santos; Alves, M.; Lauda, Diogo Ponte; Vasconcellos, Luana Marotta Reis de; Campos, Tiago Moreira Bastos; Oliveira, Ivone Regina de
    Bioactive glass (BG-45S5) production through the melting process is affected by a wide variety of parameters. This study investigated the synthesis of BG-45S5 granules and the process variables to produce a bioactive and osteoinductive BG for bone grafting applications. The melting process was initially analyzed by varying pa- rameters such as crucible type and pouring environment using P2O5 as phosphorus precursor. The obtained products were characterized by crystalline phases, characteristic chemical groups, particle size distribution, and chemical composition. Materials poured into graphite or steel molds resulted in particle sizes more suitable for applications in granular form. Using a platinum crucible yielded a chemical composition closer to the target when compared with another ceramic crucible. Subsequently, the melting process was evaluated to different phosphorus precursor (P2O5 or Na2HPO4) and melting duration (1 or 2 h) in a platinum crucible verifying their effects on the thermal behavior, chemical composition and structure of BG-45S5. Employing Na2HPO4 as a precursor led to higher glass transition and crystallization temperatures as compared to P2O5, enhancing glass homogeneity and structural stability. The product with better characteristics in terms of composition and structure was further characterized for bioactivity and cell culture behavior, showing a greater amount of mineralization nodules when compared to commercial hydroxyapatite. This is particularly due to its behavior as the solubility and interaction in biological environments.