The osteogenic effect of Germanium-doped hydroxyapatite nanoparticles on dental pulp stem cells

Abstract

Most of the applications for various forms of ion-doped hydroxyapatite have been geared towards pharmacy, dentistry and medicine. This study presents the first biological, response to germanium-doped hydroxyapatite (Ge-HAp). Viability, osteogenic differentiation induction and colony formation potential of dental pulp stem cells (DPSCs) in the presence of Ge-HAp and pure, Ge-free HAp nanoparticles was assessed. DPSCs were isolated from semiimpacted wisdom teeth extracted from systemically sound patients. MTT was used to determine cell viability after 1, 3, and 7 days of incubation. The effect of Ge-HAp on the expression level of osteodifferentiation markers (RUNX2, ALP, and OCN) was determined using RT-qPCR, and mineralized nodule formation was confirmed using Alizarin Red S staining. The colony-forming unit assay was utilized to evaluate the colony-formation potential of the DPSC. Low dosages of Ge-HAp increased cell viability compared to HAp after a week. Ge-HAp increased cell culture mineralization more than HAp. Ge-HAp substantially upregulated all three osteogenic markers relative to control and Ge-free HApexposed cells. HAp and especially Ge-HAp hindered stem cell colony formation. As demonstrated above, Ge-doped HAp nanoparticles have great promise in regenerative medicine due to their biocompatibility and osteoinductivity.