Stimulated osteoblastic proliferation by mesoporous silica xerogel with high specific surface area.

Specific surface area is a critical parameter of mesoporous silica-based biomaterials, however, little is known about its effects on osteoblast responses in vitro. In the present study, mesoporous silica xerogels (MSXs) with different surface area (401, 647 and 810 m(2)/g, respectively) were synthesized by a sol-gel process. Surface silanol contents decreased with the increase of surface area with which protein adsorption capability positively correlated. And the apatite-like surface seemed to form faster on MSXs with higher surface area determined by XRD analysis. Using MG63 osteoblast-like cells as models, it was found that cell proliferations were promoted on MSXs with higher surface area, based on the premise that the effects of Si released from materials on osteoblast viability were excluded by real-time Transwell(®) assay. RT-PCR results indicated cell adhesion-related integrin subunits α5 were up-regulated by higher surface area at day 1, which was further confirmed by flow cytometry analysis. The data suggest that increasing SSA of MSXs could promote surface cellular affinity by adsorbing serum proteins and accelerating apatite-like layer formation, which results in promoted osteoblastic proliferation via integrin subunit α5 at initial adhesion stage. Regulating SSA, an effective approach in designing mesoporous silica-based materials, provides an alternative method to obtain desirable tissue-response in bone regeneration and drug-delivery system.