Strontium-Delivering Glasses with Enhanced Bioactivity: A New Biomaterial for Antiosteoporotic Applications?

Abstract

International audienceBioactive glasses exhibit great performances for bone tissue regeneration. In biological conditions, they spontaneously bond to bone tissues while actively stimulating bone growth. Crucial parameters for the material's bioactivity are the kinetics of formation of the interfacial calcium phosphate layer at the glass surface, as well as the release of critical concentrations of ionic dissolution products capable of stimulating cellular responses. In this paper we report the remarkable bioactivity properties of strontium-delivering sol−gel-derived glasses in the SiO2−CaO−SrO system. The glasses were tested in vitro and the interface between the glass and the biological medium was chemically mapped using highly sensitive nuclear microprobes. We prove the ability of our materials to form a phosphocalcic layer at their periphery with increased kinetics of reaction. Our key result is the demonstration that Sr-doped glasses can deliver controlled doses of strontium toward the biological medium. That is the determinant for bone tissue regeneration, as far as strontium is known to positively act on bone remodeling. Sr-delivering glasses could further represent an alternative to the constraining oral administration of strontium in treatment of osteoporosis

Effects of strontium-doped bioactive glass on the differentiation of cultured osteogenic cells

“…Indeed, Si concentration continuously increased with incubation time (the "sharp decreases" observed in the Si curves corresponded to the renewing of the media after 72 h of interaction). Finally, in line with previous studies (Lao et al, 2008), only one significant difference was observed in the dissolution behaviour of the materials: the quantity of Sr released by B75-Sr5 was about five time greater than those released by B75-Sr1.…”

“…The growing evidence of the beneficial effects of strontium on bone justifies the increasing interest in Sr incorporation into biomaterials for hard tissue repair. Thus, strontium-doped bioactive glasses have been recently developed via a sol-gel method that enables a better control of the reaction kinetics (Lao et al, 2008;Lao et al, 2009).…”

Novel strontium-doped bioactive glass nanoparticles enhance proliferation and osteogenic differentiation of human bone marrow stromal cells

“…A continuous effect of Sr on the cells can consequently be assumed. Lao et al investigated the release of Sr in DMEM using Srdoped mesoporous bioactive glass discs and particles (0, 1, 5 wt.-%) (Lao et al 2008).…”

“…Additionally, influences of Sr on bioactive glasses were found, such as induced and accelerated formation of surface bone-like apatite layers and reduced dissolution of the mesoporous glasses (Lao et al 2008). …”

Biomaterials Obtained by Gelation

“…A last efficient additive is strontium, which inhibits the osteoclast activity and is beneficial to patients suffering from osteoporosis (Lao et al 2008). It was found to stimulate the formation of several types of proteins (Isaac et al 2011).…”