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| Author(s): |
Mariana de Oliveira Silva
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Química |
| Defense date: | 2018-08-28 |
| Examining board members: |
Celso Aparecido Bertran;
Italo Odone Mazali;
Mariana Motisuke
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| Advisor: | Celso Aparecido Bertran |
| Abstract | |
The 45S5® bioglass is one of the most promising materials to repair bone tissue damage, especially in Bucco-Maxillo interventions, due to its biocompatibility, bioactivity and osteoinductivity. However, due to its reduced sintering window, attempts to construct scaffolds with a good compromise between porosity and mechanical properties of this bioglass result in crystallization, which affects the properties that make it such a distinctive material. In this dissertation, a strategy was developed for the production of 45S5® bioglass "scaffolds" using large and small particles produced by the melting-quenching technique. The "scaffolds" were prepared by agglutinating these particles with a sol-gel of the same composition and adding a porogenic agent, then moulding into cylinders. Sol-gel catalyzed by nitric and formic acids were evaluated. The association of Renex 120® surfactant with sol-gel was also studied in order to improve the wettability of the bioglass particles. Hydrogen peroxide with surfactant and polystyrene microspheres were evaluated as porogenic agents. In order to obtain adequate porosity and mechanical strength, ratios of particles/sol-gel and particles/polystyrene microspheres were studied, as well as various calcination methodologies. Initially, only the large particles were tested, and the results showed that the sol-gel catalyzed by formic acid 0.1 mol L-1 leads to the best coating and the use of polystyrene microspheres as a porogenic agent allowed to obtain scaffolds with interconnected pores greater than 50 µm. For the small particles, the same methodology was used, obtaining interconnected pores bigger than 100 µm. The best heat treatment was planned considering the kinetic stability of the glasses. The "scaffolds" were thermally treated in stages to eliminate solvents (120 °C for 3 hours), organic matter (250 °C for 6 hours) and nitrates (400 °C for 12 hours) and finally calcined (1200 °C for 10 seconds). The degree of crystallization obtained was much lower than that reported in the literature for 45S5® "scaffolds". The partial crystallization can be justified by the possible formation of crystals during calcination due to the reaction of the particles with the sol-gel. The characterization of the "scaffolds" showed that this material has the expected composition and the leaching tests show a typical behaviour of uncrystallized 45S5® bioglass. The results confirm that the strategy of joining bioglass particles with a sol-gel of the same composition represents a valid alternative for the construction of bioglass "scaffolds" with reduced crystallinity, especially when prepared with the small particles (AU) | |
| FAPESP's process: | 17/12932-6 - 45S5 Bioglass Scaffolds to repare damages in bone tissue |
| Grantee: | Mariana de Oliveira Silva |
| Support Opportunities: | Scholarships in Brazil - Master |