Tetraethyl orthosilicate (TEOS) and trimethyl orthosilicate (TMOS) alkoxysilanes are expensive common precursors for silicate based solgel derived bioactive glasses. Facile approa- ches involving low cost substitutes ...Tetraethyl orthosilicate (TEOS) and trimethyl orthosilicate (TMOS) alkoxysilanes are expensive common precursors for silicate based solgel derived bioactive glasses. Facile approa- ches involving low cost substitutes are a necessity for bioactive glass implants in bone regeneration therapy. Quaternary SiO2–Na2O–CaO– P2O5 bioactive glass was prepared by the solgel method from locally sourced sand as precursor. The monolith glass material obtained was subjected to immersion studies in simulated body fluid (SBF) for 21 days. The surface morphology and composition of the glass before and after immersion in SBF was studied using SEM-EDX, while pH analysis was used to monitor changes on the glass surface in SBF solution. FTIR was used to confirm apatite formation on the material. Results showed that the concentration of Ca, P and C increased on the surface of the glass sample as immersion time increased, which was attributed to the formation of carbonated hydroxyapatite (HCA). The material shows ability to bond to bone making it a promising scaffold material for bone repair.展开更多
Porous silica was synthesized via the sol-gel process using clay obtained locally from Ijero-Ekiti in Ekiti State, Nigeria and compared with silica synthesized under similar conditions from sodium metasilicate (Na2SiO...Porous silica was synthesized via the sol-gel process using clay obtained locally from Ijero-Ekiti in Ekiti State, Nigeria and compared with silica synthesized under similar conditions from sodium metasilicate (Na2SiO3) obtained comer- cially. The clay was initially refluxed with sodium hydroxide (NaOH) for 2 hours to extract SiO2 to form Na2SiO3, which was subsequently hydrolyzed to form a gel. The gel obtained was washed with deionized water to get rid of im-purities, dried and calcined at 800°C for 3 hours. The obtained silica powders were characterized using atomic absorp-tion spectrophotometer, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that the vibrational modes and diffraction patterns of the silica derived from com-mercial Na2SiO3 and that prepared from clay were similar containing pure amorphous SiO2. The morphology of the commercially obtained silica showed better arrangement of particles and exhibited slightly lesser porosity (62.4%) compared to that derived from clay which had a porosity of 65.5%. The result indicates that clay has a potential for use as an environmentally safe and economic starting material for preparing porous silica instead of high quality precursors.展开更多
Bioceramic material of the quaternary system;SiO2- CaO-Na2O-P2O5 that has composition similar to Bio- glass? 45S5 was prepared by the sol-gel method from locally obtained bentonite clay (BTC). The monolith obtained wa...Bioceramic material of the quaternary system;SiO2- CaO-Na2O-P2O5 that has composition similar to Bio- glass? 45S5 was prepared by the sol-gel method from locally obtained bentonite clay (BTC). The monolith obtained was sintered at 1000?C for 2 h to facilitate densification and phase transformation. X-ray diffraction (XRD) analysis revealed the presence of sodium calcium silicate, Na2Ca2Si3O9 as major crystal phase, and another secondary orthorhombic phase, NaCaPO4. Fourier transform infrared (FTIR) spectroscopic investigation confirmed the presence of Si-O-Si bonds and a crystalline phosphate in the glass network. Scanning electron microscopy (SEM) revealed a network of micropores and interconnected macropores. Overall, the material displays features amenable for possible utilization in tissue engineering scaffolds.展开更多
Bioactive glass ceramic with SiO2-Ca2O-Na2O-P2O5 composition was prepared by the sol-gel method using sodium metasilicate (Na2SiO3) as silica source. The monolith obtained was sintered at 1000?C for 2 hours after whic...Bioactive glass ceramic with SiO2-Ca2O-Na2O-P2O5 composition was prepared by the sol-gel method using sodium metasilicate (Na2SiO3) as silica source. The monolith obtained was sintered at 1000?C for 2 hours after which X-ray diffraction (XRD) analysis showed presence of combeite (Na2Ca2Si3O9) as the crystalline phase. In vitro bioactivity test conducted on the material using simulated body fluid (SBF) showed the formation of carbonated hydroxyapatite on its surface. The material during the SBF test was observed to transform from a mechanically strong crystalline phase Na2Ca2Si3O9 to an amorphous phase after incubation for 14 days indicating that the material was biodegradable. Scanning electron microscopy (SEM) was used to investigate the surface morphology, while Fourier transform infrared (FTIR) spectroscopy facilitated the confirmation of hydroxyapatite (HA) formation. The monolith material obtained may be a good candidate for application in tissue engineering scaffolds.展开更多
文摘Tetraethyl orthosilicate (TEOS) and trimethyl orthosilicate (TMOS) alkoxysilanes are expensive common precursors for silicate based solgel derived bioactive glasses. Facile approa- ches involving low cost substitutes are a necessity for bioactive glass implants in bone regeneration therapy. Quaternary SiO2–Na2O–CaO– P2O5 bioactive glass was prepared by the solgel method from locally sourced sand as precursor. The monolith glass material obtained was subjected to immersion studies in simulated body fluid (SBF) for 21 days. The surface morphology and composition of the glass before and after immersion in SBF was studied using SEM-EDX, while pH analysis was used to monitor changes on the glass surface in SBF solution. FTIR was used to confirm apatite formation on the material. Results showed that the concentration of Ca, P and C increased on the surface of the glass sample as immersion time increased, which was attributed to the formation of carbonated hydroxyapatite (HCA). The material shows ability to bond to bone making it a promising scaffold material for bone repair.
文摘Porous silica was synthesized via the sol-gel process using clay obtained locally from Ijero-Ekiti in Ekiti State, Nigeria and compared with silica synthesized under similar conditions from sodium metasilicate (Na2SiO3) obtained comer- cially. The clay was initially refluxed with sodium hydroxide (NaOH) for 2 hours to extract SiO2 to form Na2SiO3, which was subsequently hydrolyzed to form a gel. The gel obtained was washed with deionized water to get rid of im-purities, dried and calcined at 800°C for 3 hours. The obtained silica powders were characterized using atomic absorp-tion spectrophotometer, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that the vibrational modes and diffraction patterns of the silica derived from com-mercial Na2SiO3 and that prepared from clay were similar containing pure amorphous SiO2. The morphology of the commercially obtained silica showed better arrangement of particles and exhibited slightly lesser porosity (62.4%) compared to that derived from clay which had a porosity of 65.5%. The result indicates that clay has a potential for use as an environmentally safe and economic starting material for preparing porous silica instead of high quality precursors.
文摘Bioceramic material of the quaternary system;SiO2- CaO-Na2O-P2O5 that has composition similar to Bio- glass? 45S5 was prepared by the sol-gel method from locally obtained bentonite clay (BTC). The monolith obtained was sintered at 1000?C for 2 h to facilitate densification and phase transformation. X-ray diffraction (XRD) analysis revealed the presence of sodium calcium silicate, Na2Ca2Si3O9 as major crystal phase, and another secondary orthorhombic phase, NaCaPO4. Fourier transform infrared (FTIR) spectroscopic investigation confirmed the presence of Si-O-Si bonds and a crystalline phosphate in the glass network. Scanning electron microscopy (SEM) revealed a network of micropores and interconnected macropores. Overall, the material displays features amenable for possible utilization in tissue engineering scaffolds.
文摘Bioactive glass ceramic with SiO2-Ca2O-Na2O-P2O5 composition was prepared by the sol-gel method using sodium metasilicate (Na2SiO3) as silica source. The monolith obtained was sintered at 1000?C for 2 hours after which X-ray diffraction (XRD) analysis showed presence of combeite (Na2Ca2Si3O9) as the crystalline phase. In vitro bioactivity test conducted on the material using simulated body fluid (SBF) showed the formation of carbonated hydroxyapatite on its surface. The material during the SBF test was observed to transform from a mechanically strong crystalline phase Na2Ca2Si3O9 to an amorphous phase after incubation for 14 days indicating that the material was biodegradable. Scanning electron microscopy (SEM) was used to investigate the surface morphology, while Fourier transform infrared (FTIR) spectroscopy facilitated the confirmation of hydroxyapatite (HA) formation. The monolith material obtained may be a good candidate for application in tissue engineering scaffolds.
