Effect of the internal microstructure in rapid-prototyped polycaprolactone scaffolds on physical and cellular properties for bone tissue regeneration

Biomedical scaffolds should be designed to optimize their inter-microstructure to enable cell infiltration and nutrient/waste transport. To acquire these properties, several structural parameters, such as pore size, pore shape, porosity, pore interconnectivity, permeability, and tortuosity are required. In this study, we explored the effect of tortuosity on the viable cell proliferation and mineralization of osteoblast-like-cells (MG63) in polycaprolactone scaffolds. For analysis, we designed four different scaffolds of various tortuosities ranging from 1.0 to 1.3 under the same porosity (56 %) and 100 % pore interconnectivity. The pore size of the scaffolds was set as 150 and 300 μm, and a mixture of these sizes. We found that despite the porosity being same, the elastic modulus was dependent on the pore size of the scaffolds due to the distributed stress concentration. In addition, the relative water movement within scaffolds was also related to the internal microstructure. Cell viability and Ca ²⁺ deposition of the cell-seeded scaffolds showed that the proliferation of viable cells and mineralization in the scaffolds with appropriate tortuosity (1.2) was relatively high compared to those of the scaffolds displaying low (1.05 and 1.1) or high (1.3) tortuosity. Our findings indicated that the internal microstructure of the scaffolds may influence not only the physical properties, but in addition the cellular behavior.