58S mesoporous bioactive glass as a structural enhancer in α-TCP-based bone cements: gains in strength, challenges in bioactivity

• Adding mesoporous bioactive glass extends setting time and strengthens bone cements. • Higher bioactive glass content reduces total porosity and increases closed porosity. • Plain cement induces stronger early osteogenic response due to higher open porosity. • Osteogenic markers trended higher in MBG groups without significant difference. Calcium phosphate bone cements (CPCs) are promising injectable bone substitutes but are limited by insufficient mechanical strength, prolonged setting time, and inadequate degradation profile. This study investigates the incorporation of mesoporous bioactive glass (58S MBG) into α-tricalcium phosphate (α-TCP)-based CPCs to enhance their physicochemical and biological performance. Composites containing 0–15 wt% MBG were fabricated and evaluated across multiple powder-to-liquid ratios. MBG addition extended final setting time from 9 to 42 min and increased compressive strength over threefold (from 3.39 to 10.40 MPa). Total porosity decreased (78 % to 61 %) while closed porosity increased, improving structural integrity. BG0 (0 %), BG5 (5 %), and BG9 (9 %) were selected for further in vitro testing with human mesenchymal stem cells. While BG0 supported early alkaline phosphatase (ALP) activity, BG5 and BG9 showed prolonged ALP response and upregulation of key osteogenic markers (ALP, COL1, RUNX2, SP7). Osteocalcin expression remained low across groups, indicating limited late-stage differentiation within the study period. The results demonstrate that MBG-modified CPCs offer enhanced mechanical performance and support osteogenic activity in vitro . These findings underscore the potential of MBG integration for optimizing CPC formulations aimed at minimally invasive bone regeneration applications.