Cell uptake and biomineralization pathway of nMBG in MSCs cells investigated combining cryo-soft X-ray tomography with XANES at the Ca L2,3 edges

Mesoporous bioactive glass nanoparticles (nMBG) represent a promising material for bone regeneration; however, their intracellular behaviour remains poorly understood. The bioactivity of nMBG is influenced by both the Si/Ca ratio and their mesoporous structure, which impact ion release, cellular internalization, and osteogenic differentiation. In a previous study, we investigated nMBG compositions Si100, Si90Ca10, and Si60Ca40 (w/w) and observed that excess calcium destabilizes the silica network, thereby altering osteogenic potential. Notably, only specific calcium levels were found to enhance the differentiation of human mesenchymal stem cells (hMSCs). This proposal at ALBA aims to elucidate the effects of Si/Ca composition on nMBG internalization, subcellular localization, and intracellular mineralization, providing valuable insights for bone tissue engineering. To achieve a deeper understanding of nMBG performance in hMSCs, we propose to analyze frozen-hydrated MSCs in contact with nMBG at various time points using a combination of cryosoft X-ray tomography and XANES microscopy. The primary objective is to characterize the uptake, localization, and calcium phosphate mineral deposition at the Ca L2,3 edges with nanoscale spatial resolution and nano-TXM within hMSCs during their differentiation into osteoblasts. This investigation will demonstrate the ability of nMBG to induce the formation of a bone-like mineral phase in biologically relevant fluids.