Bovine fibronectin

MG63 osteoblast-type cells and hMSCs were grown using previously described protocols^{20 (link)} with some modifications depending on the type of cell culture medium employed. Three types of culture media were used in different experiments, with all reagents procured from Gibco^® (Life Technologies Ltd, UK) unless mentioned otherwise: (1) low-glucose Dulbecco’s modified Eagle medium (DMEM) supplemented with fetal calf serum (FCS; 10% v v⁻¹) and penicillin–streptomycin (1%); (2) osteogenic medium (OM), prepared as per previously explained methods²¹ and comprising low-glucose DMEM, FCS (10% v v⁻¹), penicillin–streptomycin (1%), Fungizone (0.1%), dexamethasone (0.1 µM), ascorbic acid 2-phosphate (0.2 mM), and glycerol 2-phosphate (10 mM; last three chemicals procured from Sigma–Aldrich, UK); and (3) a commercially available mesenchymal stem cell growth medium DXF (PromoCell GmbH, Germany). Since DXF does not contain cell attachment and spreading factors, the surface of the cell culture flask was treated with bovine fibronectin (10 µg mL⁻¹; PromoCell GmbH) in phosphate buffered saline (PBS) for 1 h prior to cell seeding in order to facilitate cell attachment and cytoplasmic spreading.