Development and characterization of three-dimensional layered structures with gel beads for bone tissue engineering

Abstract

We designed this study to evaluate the application of alginic acid gel beads, which are known to facilitate increased water retention. These scaffolds were coated with an aqueous solution of the same material creating a concentration gradient between the gel beads and the sodium alginate aqueous solution, which fills the surrounding 3D layered structure to improve stability. The aim of this study was to enhance the mechanical properties and stability of these scaffolds to promote effective proliferation and differentiation in the native setting.The three-dimensional gel beads were formed by reacting a sodium alginate aqueous solution with a calcium chloride aqueous solution. The gel beads were evaluated by diameter and sphericity. As the concentration of sodium alginate increased, the diameter of the gel beads increased and sphericity became approximately 1. Then the three-dimensional structure was formed by layering the gel beads on a 24-well plate. The three-dimensional layered structures with gel beads were tested using a universal testing machine and evaluated compressive mechanical property. The modulus of elasticity for the three-dimensional layered structures with gel beads was the highest when the concentrations of the gel beads and surroundings were the same. In vitro experiment, the cell number and ALP activity were also measured by plate reader. The results of the in vitro experiments showed no difference in the cell numbers with the control, but the ALP activity tended to be higher with the samples having a high modulus of elasticity. It is concluded that three-dimensional layered structures with gel beads were effective for bone tissue regeneration as a scaffold.