Osteogenic potential of human dental pulp stem cells, and human dermal fibroblasts exposed hydroxyapatite nanoparticles: A comparative in vitro study.

This study aimed to evaluate the osteogenic response of human dermal fibroblasts (hDFs) and human dental pulp stem cells (hDPSCs) when exposed to hydroxyapatite nanoparticles (HA-NPs), which are commonly employed biomaterials in the field of bone regeneration. The sol-gel method was employed to synthesize HA-NPs. Cell viability was assessed using the MTT assay after 24 and 72 hours of exposure to HA-NPs. Osteogenic differentiation was assessed through Alizarin red S staining (ARS), alkaline phosphatase (ALP) activity assay, and quantitative real-time PCR (qPCR) to evaluate the expression levels of osteogenic markers, including BMP-2, VEGF-A, RUNX2, and IL-6. The HA-NPs had a nanorod shape, with dimensions of 17-29 nm in width and 62-89 nm in length. Both hDPSCs and hDFs demonstrated enhanced osteogenic potential when exposed to HA-NPs, as indicated by increased ARS staining for calcium deposition and elevated ALP activity. Gene expression analysis showed up-regulation of BMP-2 and VEGF-A and down-regulation of RUNX2 in both cell types. IL-6 expression markedly increased in hDFs but did not show significant changes in hDPSCs compared to the control group. The findings of this study suggest that HA-NPs may enhance the osteogenic capability of hDPSCs and hDFs. The results demonstrate that while fibroblasts exhibit some mineralization potential, hDPSCs are the most suitable cell type for bone regenerative applications.