Search

To evaluate the in vitro wound healing and osteogenic activity of dexamethasone-doped polymeric nanoparticles (Dex-NPs) to be employed as immunomodulator agent aiding in the treatment of peri-implantitis. Polymeric nanoparticles (NPs) were obtained through a polymerization precipitation technique. The NPs are composed of 2-hydroxyethyl methacrylate as the backbone monomer, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate acting as a cross-linker. NPs were doped with dexamethasone (Dex) through immersion in a Dex aqueous solution for 2 h, at room temperature and under constant shaking, in order to reach the Dex adsorption equilibrium. Subsequently, the suspensions were centrifuged, and the particles were detached from the supernatant. Different eluates of NPs were prepared at concentrations (0.1,1,10 and 100 µg•mL-1). Undoped nanoparticles were also included in the study. An osteogenic culture medium (Osteodiff®) was employed as a positive control. Bone marrow mesenchymal stromal cells (BMMSC) were cultured. Cell migration/proliferation at 24, 48 and 72 h was assessed via a wound-healing assay and osteogenic activity was analyzed by cell mineralized nodule formation through Alizarin Red staining. Statistical differences were assessed by ANOVA and Tukey's test (p<0.05). Wound healing assay demonstrated an adequate cell migration and proliferation when Dex-NPs were employed at 0.1 and 1 µg•mL-1. Moreover, undoped NPs neither exert differences with the control even at 10 µg•mL-1 (Graphic). Mineralized nodule formation was evidenced in all cases when any of the tested NPs were employed, except for the lowest tested NPs concentration (0.1 µg•mL-1) (Figure). Favorable in vitro wound healing and osteogenic activity has been demonstrated when NPs were used at 1 µg•mL-1. Attained proliferation, migration and osteogenic activity may encourage the clinical use of this new therapeutic tool. Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER), grants numbers [PID2020-114694RB-I00 and PID2020-115887GB-I00 MINECO/AEI/FEDER/UE]. M. Toledano-Osorio holds a FPU fellowship from the Ministry of Universities [FPU20/00450]. [Display omitted] [ABSTRACT FROM AUTHOR]

To evaluate the in vitro biocompatibility of dexamethasone-doped polymeric nanoparticles (Dex-NPs) to be employed as immunomodulator agent aiding in the treatment of peri-implantitis. Polymeric nanoparticles (NPs) were obtained through a polymerization precipitation technique. The NPs are composed of 2-hydroxyethyl methacrylate as the backbone monomer, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate acting as a cross-linker. NPs were doped with dexamethasone (Dex) through immersion in a Dex aqueous solution for 2 h, at room temperature and under constant shaking, in order to reach the Dex adsorption equilibrium. Subsequently, the suspensions were centrifuged and the particles were detached from the supernatant. Different eluates of NPs were prepared at concentrations (0.1,1,10 and 100 µg•mL-1). Undoped nanoparticles were also included in the study. Bone marrow mesenchymal stromal cells (BMMSC) were cultured. The cell cytotoxicity and viability was assessed by analyzing the resazurin-based assays after 24, 48, 72 and 168 h of culture, light absorbance per well was recorded by means of a microplate reader. Phalloidin staining was used to analyze changes in cell morphology and in the actin cytoskeleton structure and organization. Cell cycle analysis was performed by flow cytometry to evaluate cells viability after exposure to the different NPs. Statistical differences were assessed by ANOVA and Tukey's test (p<0.05). Cytotoxicity was only produced on cells cultured in the presence of Dex-NPs and undoped NPs when using concentrations of 10 or 100 µg•mL-1, after 7d (Graphic 1). Phalloidin staining demonstrated cells' structural integrity, except when NPs were used at 100 µg•mL-1. In this case nuclei alterations were evidenced. After cells' cycle analysis, none of the NPs used disturbed the cell cycle, there being a similar percentage of cells in each of the stages of the cell cycle; except for NPs at 100 µg•mL-1, it was shown that cell division was interrupted and cells remained at DNA synthesis stage (Figure 1). Favorable in vitro cytocompatibility has been demonstrated when NPs were used at 0.1 and 1 µg•mL-1. Biological activity of doped NPs at these concentrations has to be demonstrated in order to facilitate the clinical use of this new therapeutic tool. Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER), grants numbers [PID2020-114694RB-I00 and PID2020-115887GB-I00 MINECO/AEI/FEDER/UE]. M. Toledano-Osorio holds a FPU fellowship from the Ministry of Universities [FPU20/00450]. [Display omitted] [ABSTRACT FROM AUTHOR]