Synthesis, neutralization and blocking procedures of organic/inorganic hybrid scaffolds for bone tissue engineering applications

Bioactive glasses (BaG) can bind to human bone tissues and have been used in many biomedical applications for the last 30 years. However they usually are weak and brittle. On the other hand, composites that combine polymers and BaG are of particular interest, since they often show an excellent balance between stiffness and toughness. Bioactive glass-poly(vinyl alcohol) foams to be used in tissue engineering applications were previously developed by our group, using the sol-gel route. Since bioactive glass-polymer composite derived from the sol-gel process cannot be submitted to thermal treatments at high temperatures (above 400A degrees C), they usually have unreacted species that can cause cytotoxicity. This work reports a technique for stabilizing the sol-gel derived bioactive glass/poly(vinyl alcohol) hybrids by using glutaraldehyde (GA), NH4OH solutions and a blocking solution containing bovine serum albumin. PVA/BaG/GA hybrids were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM/EDX) analyses. Moreover, MTT (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) biocompatibility and cytotoxicity assays were also conducted. The hybrids exhibited pore size varying from 80 to 820 mu m. After treatments, no major changes in the pore structure were observed and high levels of cell viability were obtained.