  A mesoporous bioactive glass (MBG) of molar composition 75SiO2-20CaO-5P2O5
(MBG-75S) has been synthetized as a potential bioceramic for bone regeneration
purposes. X-ray diffraction (XRD), Fourier transform infrared spectroscopy
(FT-IR), nitrogen adsorption studies and transmission electron microscopy (TEM)
demonstrated that MBG-75Spossess a highly ordered mesoporous structure with
high surface area and porosity, which would explain the high ionic exchange
rate (mainly calcium and silicon soluble species) with the surrounded media.
MBG-75S showed high biocompatibility in contact with Saos-2 osteoblast-like
cells. Concentrations up to 1 mg/ml did not lead to significant alterations on
either morphology or cell cycle. Regarding the effects on osteoclasts, MBG-75S
allowed the differentiation of RAW-264.7 macrophages into osteoclast-like cells
but exhibiting a decreased resorptive activity. These results point out that
MBG-75S does not inhibit osteoclastogenesis but reduces the osteoclast
boneresorbing capability. Finally, in vitro studies focused on the innate
immune response, evidenced that MBG-75S allows the proliferation of macrophages
without inducing their polarization towards the M1 pro-inflammatory phenotype.
This in vitro behavior is indicative that MBG-75S would just induce the
required innate immune response without further inflammatory complications
under in vivo conditions. The overall behavior respect to osteoblasts,
osteoclasts and macrophages, makes this MBG a very interesting candidate for
bone grafting applications in osteoporotic patients.
