Sol-gel synthesis of bioactive glass scaffolds for tissue engineering: effect of surfactant type and concentration

Well-defined structural characteristics are some of the exigencies that have to be attended when scaffolds for bone tissue cell culture are designed. A high porosity (70-90%) and a high specific surface area and an average pore size>150 microm will contribute to allow cell migration throughout the structure, adhesion, and proliferation. At the same time, the biodegradation of the material should occur in a proper rate. One way to reach a structure with these characteristics is to produce foams during sol-gel processing of bioactive glasses (system CaO--SiO2--P2O5). The addition of a surfactant in the sol-gel solution is necessary for foam formation and to maintain its stability until complete gelation occurs. This study presents the performance evaluation of two surfactants [sodium lauryl ether sulfate (SLES) and Tergitol] to determine optimum conditions for foaming ability and stability properties. The anionic surfactant SLES showed better results in terms of foam volume and its stability. Bioactive glass foams obtained with use of this surfactant presented a higher and interconnected porosity. The porosity of the scaffolds produced was 90%, and the macropore size ranged from 100 to 500 microm.