Ion-selective electrodes to monitor osteoblast-like cellular influence on the extracellular concentration of calcium

Abstract

In bone tissue engineering, the composition of the ionic extracellular environment (IEE) can determine both cellular fate and a biomaterial ’ s development and performance. Therefore, precise control of the IEE and a perfect understanding of the dynamic changes that it can be subject to due to cellular activity ishighlydesired.Toachievethis,weinitiallymonito redhowtwostandardosteoblast-likecellmodelsthat expressedeitherhighorlowalkalinephosphataseactivity-SAOS-2andMG63cells,respectively-affected the extracellular concentrations of calcium and phosphate during long-term cultures. It was observed that cellular in fl uence onthe IEE varied greatly between the two models and could be linked to the capac- ity of cells to deposit calcium in the extracellular matri x. Miniaturized ion-selective electrodes that could allow for real-time monitoring ofcalcium in aminimally invasive waywere then constructed.The electro- des were characterized in standard in vitro cell culture environments, prior to being successfully applied for periods of 24h, to record the dynamics of cell-induced deposition of calcium in the extracellular matrix, while using osteogenic media of either high or low concentrations of phosphate. As a result, this study provides the background and technological means for the non-destructive evaluation of the IEE in vitro and allows for the optimization and development of better models of bone tissue construction