Bioactive sol-gel foams for tissue repair.

Bioactive glasses are known to have the ability to regenerate bone, but their use has been restricted mainly to powder, granules, or small monoliths. This work reports on the development of sol-gel foams with potential applications as bone graft implants or as templates for the in vitro synthesis of bone tissue for transplantation. These bioactive foams exhibit a hierarchical structure with interconnected macropores (10-500 microm) and a mesoporous framework typical of gel-glasses (pores of 2-50 nm). The macroporous matrixes were produced through a novel route that comprises foaming of sol-gel systems. Three glass systems were tested to verify the applicability of this manufacturing route, namely SiO(2), SiO(2)-CaO, and SiO(2)-CaO-P(2)O(5). This new class of material combines large pores to support vascularization and 3-D tissue growth with the ability that bioactive materials have to provide bone-bonding and controlled release of ionic biologic stimuli to promote bone cell proliferation by gene activation.