Periodic microstructures on bioactive glass surfaces enhance osteogenic differentiation of human mesenchymal stromal cells and promote osteoclastogenesis in vitro.

Bioactive glasses (BG) are known for their ability to bond to hard and soft tissues. We hypothesized that the stimulation of bone remodeling, including cellular bone forming and bone resorbing processes, can be increased by applying periodic microstructures on the glass surfaces in vitro. To test our hypothesis, two different BG (45S5 and 13-93) were microstructured in a groove-and-ridge pattern of different sizes by a novel casting process and tested in cell culture experiments using human mesenchymal stromal cells (hMSCs) and RAW 264.7 cells. The microstructures induced contact guidance of hMSCs and increased osteogenic marker gene expression of the stem cells, compared to non-structured glass surfaces as verified by ELISA and quantitative real-time PCR (qPCR) analyses. Furthermore, the structures stimulated the differentiation of RAW cells to osteoclast-like cells confirmed by TRAP gene expression and their resorption activity causing visible resorption lacunae. Our results demonstrate that periodically microstructured BG (especially 45S5) might improve the osteogenic differentiation of hMSCs and influence the activity of material resorbing cells in vitro. Hence, microstructuring of BG could enhance the remodeling process of bone substitutes critical for the formation of new bone tissue in vivo and thus be used to trigger bone remodeling kinetics in vivo. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1965-1978, 2018.