Effect of magnesium oxide nanoparticles and LED irradiation on the viability and differentiation of human stem cells of the apical papilla

Purpose Currently, regenerative endodontic treatments are gaining more and more attention, and stem cells play a significant role in these treatments. In order to enhance stem cell proliferation and differentiation, a variety of methods and materials have been used. The purpose of this study was to determine the effects of magnesium oxide nanoparticles and LED irradiation on the survival and differentiation of human stem cells from apical papilla. Methods The MTT test was used to measure the cell survival of SCAPs that had been exposed to different concentrations of magnesium oxide nanoparticles after 24 and 48 h, and the concentration with the highest cell survival rate was picked for further studies. The cells were classified into four distinct groups based on their treatment: (1) control, which received no exposure, (2) exposure to magnesium oxide nanoparticles, (3) exposure to light emitting diode (LED) irradiation (635 nm, 200 mW/cm 2 ) for 30 s, (4) exposure simultaneously with magnesium oxide nanoparticles and LED irradiation. A green approach was employed to synthesize magnesium oxide nanoparticles. Quantitative real time PCR was used to measure the gene expression of osteo/odontogenic markers such as BSP, DSPP, ALP and DMP1 in all four groups after treatment, and Alizarin red S staining (ARS) was used to determine the osteogenic differentiation of SCAPs by demonstrating the Matrix mineralization. Results The highest viability of SCAPs was observed after 24 h in concentration 1 and 10 µg/mL and after 48 h in concentration 1 µg/mL, which were not significantly different from the control group. In both times, the survival of SCAPs decreased with increasing concentration of magnesium oxide nanoparticles (MgONPs). According to the results of Real-time PCR, after 24 and 48 h, the highest differentiation of BSP, DMP1, ALP and DSPP genes was observed in the LED + MgONPs group, followed by MgONPs and then LED, and in all 3 experimental groups, it was significantly higher than control group (P < 0.05). Also, after 24 and 48 h, the density of ARS increased in all groups compared to the control group, and the highest density was observed in the MgONPs + LED and MgONPs groups. Conclusion This research concluded that exposure to SCAPs, MgONPs, and LED irradiation has a significant effect on enhancing gene expression of odontogenic/osteogenic markers and increasing matrix mineralization.