Dental Pulp Stem Cell-Derived Organoids: Advancing the Development of 3D Structures

Two-dimensional cell cultures are crucial research tools, and they have been widely used, although they are not completely representative of biological processes in vivo due to the lack of tissue architecture and complexity. Recent advances in organoid technology have addressed these limitations and are revolutionizing the tools available for in vitro culture. Although there are no unified protocols for generating organoids, they can be obtained with various techniques, leading to cell aggregation by promoting cell adhesion. This work aims to generate and characterise organoid models of dental pulp from dental pulp stem cells (DPSCs), a type of mesenchymal stem/stromal cells known for their high regenerative potential and ease of accessibility, to establish a model for translational studies. The organoids were subjected to osteogenic differentiation conditions. Cell viability was evaluated using a CCK-8 assay, while osteogenic morphology and mineralization were confirmed by Alizarin red analysis, Raman microspectroscopy, and by immunofluorescence for the lineage markers expression. The Alizarin red analysis indicated a higher presence of calcium phosphate deposits in the differentiated organoids than in the control group (CTR). These results were confirmed by spectral profiles obtained using Raman microspectroscopy, which were attributable to a hydroxyapatite-based biomaterial. Immunofluorescence analysis also revealed increased expression of odonto/osteogenic markers (RUNX and OSX), alongside reduced expression of stemness markers. In conclusion, the organoids appeared to have successfully differentiated into an osteogenic lineage, forming a mineralized matrix containing hydroxyapatite and showing increased expression of relevant lineage markers.