Calcium Carbonate/Gelatin Methacrylate Microspheres for 3D Cell Culture in Bone Tissue Engineering

Hydrogel microspheres have been widely used as cell carriers and three-dimensional cell culture matrices. However, these microspheres are associated with several unfavorable properties for bone tissue engineering applications, for example, their surface is too smooth to attach cells and they do not contain inorganic materials. This article presents a new method to overcome these disadvantages by depositing CaCO 3 crystals on the hydrogel microsphere surface. Specifically, we used a nonplanar flow-focusing microfluidic device to produce gelatin methacrylate (GelMA)-/Na 2 CO 3 -based microspheres. We subsequently obtained CaCO 3 crystals by a chemical reaction between Na 2 CO 3 and CaCl 2 . The efficacy of this method was demonstrated by in vitro experiments with human umbilical vein endothelial cells (HUVEC) and immortalized mouse embryonic fibroblasts (iMEF). Cell culture on GelMA/CaCO 3 microspheres showed that cells can easily attach and adhere to GelMA/CaCO 3 microspheres and maintain high viability. Alkaline phosphatase (ALP) expression was increased as well. These results suggest that this novel microsphere has a high potential for bone tissue engineering applications.