Calcium phosphate surface treatment of bioactive glass causes a delay in early osteogenic differentiation of adipose stem cells

Abstract

Human adipose stem cells (ASCs) combined with osteostimulative material provide an attractive approach for clinical bone regeneration. The effect of calcium phosphate (Ca-P) surface treatment of three-dimensional bioactive glass scaffolds on the attachment, proliferation, and osteogenic differentiation of ASCs was studied. Three types of bioactive glass scaffolds (nontreated, thick and thin Ca-P treated) were compared. All scaffold types supported ASC attachment, spreading, and proliferation equally as detected by scanning electron microscopy, fluorescence staining, and DNA measurement. Indices of osteogenic differentiation including the expression of osteopontin and alkaline phosphatase (ALP) were consistently higher in the nontreated and thin Ca-P-treated scaffolds when compared with thick Ca-P-treated scaffolds at 2 weeks. ASCs cultured on nontreated bioactive glass scaffolds showed significantly higher ALP activity when compared with both thin and thick Ca-P-treated scaffolds after 1 week in culture, but these differences equalized between the three scaffolds by the 2-week time point. In conclusion, osteogenic differentiation appears to be delayed on the Ca-P surface-treated scaffolds. This delay is more pronounced with thick Ca-P treatment of the scaffolds.