Abstract
The use of biomaterials capable of generating a biological response has been one of the biggest progresses in regenerative medicine, due to their ability to support growth stimulation and damaged tissue regeneration. In this context, bioceramics, particularly bioactive glass (BG), were the subject of many studies. The technique of porogen agent addition for the synthesis of scaffolds is an interesting procedure, because several types of porogen agents can be used. The aim of the present work was to obtain scaffolds using four porogen agents and to evaluate the effects that a change in treatment temperature can have on their crystallinity. Scaffolds of sol-gel bioactive glass 100S (100% SiO2) using as porogen agents paraffin 1, paraffin 2, wax and CMC (carboxymethyl cellulose) were synthesized and characterized. As the best results were obtained with paraffin 1, scaffolds 58S (60%SiO2-36%CaO-4%P2O5) and 100S using paraffin 1 as porogen agent were prepared. The scaffolds were submitted to different treatment temperatures to evaluate the effect on their crystallinity. Pore structure was analyzed by scanning electron microscopy and micro-computed tomography. Scaffolds presented satisfactory pore size and pore size distribution, important characteristics for scaffolds because they allow cell migration, nutrient transport, vascularization and tissue ingrowth. X-ray powder diffraction showed the amorphous nature of the scaffolds. At 900 °C, scaffolds BG 58S and 100S showed a small increase in crystallinity. BET analysis (N2-adsorption) indicated a mesoporous structure. The specific surface area varied from 73.2 m2/g for scaffold 58S treated at 800 °C to 331.2 m2/g for scaffold 100S treated at 800 °C. The materials obtained showed no toxic effects by MTT cytotoxicity assays. Results showed that the development of scaffolds is possible using porogen agents, with 3D interconnected porous structure and might therefore be a potential biomaterial for bone tissue regeneration.
Keywords:
bioactive glass; porogen agent; biomaterials; sol-gel; crystallinity
