Investigating the deposition of the extracellular matrix and bone tissue development in vitro using 2D and 3D cell culture methods

The study of bone tissue development in vitro has received much attention over the years due to the increasing incidences of bone disorders worldwide. This has resulted in a growing need for improving the knowledge of bone cell physiology in order to investigate the causes and to develop potential treatments for bone diseases. One approach to this is by modelling osteoblast differentiation in vitro which usually involves culturing bone forming cells such as mesenchymal stem cells (MSCs) and bone derived cell lines such as MG-63 on two-dimensional (2D) culture plasticware. However, this culture environment results in alterations to the cell morphology, leading to changes in cell fate and differentiation potential as the microenvironment does not reflect the natural three-dimensional (3D) extracellular matrix in which cells reside in vivo. To overcome this, the development of 3D cell culture techniques has been widely investigated to better recapitulate the native environments of bone forming cells, thereby helping to enhance bone formation. This project describes the culture of bone forming cells on a 3D scaffold to investigate whether osteoblast differentiation and thereby bone formation will be enhanced when compared to 2D. Two types of bone forming cells were used in this study, primary rat MSCs and MG-63s. They were induced to undergo osteogenic differentiation via the use of osteogenic morphogens in both 2D and 3D culture conditions. Results indicated the increase in expression of osteoblast markers such as Collagen I and Alkaline Phosphatase in 3D cultures of MSCs and MG-63s. Additionally, matrix mineralisation was also suggested to be enhanced in 3D cultures. These results suggest bone formation is enhanced in 3D cell culture when compared to 2D methods and reveal the advantages of using a 3D cell culture system to model bone tissue development in vitro. However, more data and additional work is required to confirm these findings.