Preparation and evaluation of physicochemical properties of the gelatin sponge scaffold containing hydroxyapatite nanoparticles and its effect on the induction of the odontogenic activity of dental pulp stem cells

Abstract

Introduction: Regenerative endodontics, as a tissue engineering approach, has emerged recently as one of the new techniques in root canal therapy that has gained a lot of attraction. In this method stem cells which have the ability to differentiate, are used to restore lost and necrotic tissues. One of the most important factors in tissue engineering is the scaffold. The scaffold should be capable of providing sufficient support to promote cell proliferation and preserve differentiation. Therefore, scaffold composition and performance for biological applications must be considered in tissue engineering. The purpose of this study was to prepare a gelatin sponge scaffold containing hydroxyapatite nanoparticles and investigate its physicochemical properties, as well as investigate the scaffold's toxicity and its stimulating effect on the mineralization of dental pulp stem cells by assessing the activity of alkaline phosphatase enzymes, in regenerative endodontics. Materials and methods: Gelatin sponge scaffold containing hydroxyapatite nanoparticles was prepared by freeze drying method. Physicochemical properties were evaluated using conventional techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, and dynamic light scattering (DLS). Biological investigation for cell survival and differentiation of dental pulp stem cells (DPSCs) was evaluated by MTT method and alkaline phosphatase (ALP) activity techniques, respectively. For the statistical analysis of the data, one-way ANOVA and t-test were performed by SPSS version 17 software, and the significance level was considered to be p≤0.05. Results: Gelatin scaffolds containing hydroxyapatite nanoparticles had porous sponge morphologies with micrometer and nanometer pores, where all functional groups of gelatin and hydroxyapatite were present in the sponge. The average particle size of HA nanoparticles was 75 nm. Also, the XRD results showed that the sponge had a crystalline structure. In biological studies, the viability of cells grown on the scaffold did not differ from the control group on days 2, 4 and 6. Furthermore, after 14 days of cell culture on the scaffold, ALP activity increased significantly (p<0.05). Conclusion: Gelatin sponge scaffolds containing hydroxyapatite nanoparticles demonstrated favorable effects in stimulating the mineralization of dental pulp stem cells, suggesting their potential for application in root regeneration.