Effects of dexamethasone-loaded biopolymeric nanoparticles on fibroblasts and mesenchymal stem cells differentiation.

Introduction. Recently, polymeric nanoparticles (NPs) have attracted interest as delivery vehicles for molecules, with the potential to overcome poor drug solubility or cell permeability. Moreover, the synthesis of novel porous biomaterials for tissue engineering applications can benefit from coupling scaffolds with micro or nanoparticles, releasing growth factors. In this study, we developed a delivery system that provides a controlled release of dexamethasone (DXM) in Human Gingival Fibroblasts (HGFs), Human Pulpar Fibroblasts (HPFs) and Mesenchymal Stem Cells (MSCs) in vitro cultured. Methods. Preparation of drug-loaded Poly-d,l-lactide-co-glycolide (PLGA): 40 mg of PLGA and 20 mg of DXM were dissolved in 5 mL of dimethylsulfoxide. The solution was dialyzed vs 100 mL of water. Cell Differentiation: MSCs, HGFs and HPFs were exposed to DMEM with 10 mM ß-GP and 50 µg/ml ascorbic acid and containing a different DXM concentrations (0.01-10 µM). The osteogenic phenotype was assessed based on changes in alkaline phosphatase (ALP) activity and in Ca-content by Alizarin red assay. At different periods of incubation (days 7 - 21), cell cultures were analyzed for proliferation. Based on the obtained results, DXM concentration able to induce cell differentiation was selected and the experiments were repeated adding such concentration by NPs. Statistical Analysis: Data were expressed as mean ± SD. Statistical analysis was performed by ANOVA, p < 0.05 was assumed significant. Results:No Cytotoxic effects were observed in presence of NPs. ALP activity and Ca-content were quickly increased when DXM was added through NPs. Conclusions: Such formulations seem very promising for inducing cell differentiation, both in vitro and ex vivo. Future studies will focus on the ability of such systems to be used in tissue engineering applications by coupling them with biocompatible scaffolds.