Browsing by Author "Gregory, R.L."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Bioactive nanofibrous scaffolds for regenerative endodontics
    (SAGE, 2013-11) Bottino, M.C.; Kamocki, K.; Yassen, G.H.; Platt, J.A.; Vail, M.M.; Ehrlich, Y.; Spolnik, K.J.; Gregory, R.L.; Endodontics, School of Dentistry
    Here we report the synthesis, materials characterization, antimicrobial capacity, and cytocompatibility of novel antibiotic-containing scaffolds. Metronidazole (MET) or Ciprofloxacin/(CIP) was mixed with a polydioxanone (PDS)polymer solution at 5 and 25 wt% and processed into fibers. PDS fibers served as a control. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), tensile testing, and high-performance liquid chromatography (HPLC) were used to assess fiber morphology, chemical structure, mechanical properties, and drug release, respectively. Antimicrobial properties were evaluated against those of Porphyromonas gingivalis/Pg and Enterococcus faecalis/Ef. Cytotoxicity was assessed in human dental pulp stem cells (hDPSCs). Statistics were performed, and significance was set at the 5% level. SEM imaging revealed a submicron fiber diameter. FTIR confirmed antibiotic incorporation. The tensile values of hydrated 25 wt% CIP scaffold were significantly lower than those of all other groups. Analysis of HPLC data confirmed gradual, sustained drug release from the scaffolds over 48 hrs. CIP-containing scaffolds significantly (p < .00001) inhibited biofilm growth of both bacteria. Conversely, MET-containing scaffolds inhibited only Pg growth. Agar diffusion confirmed the antimicrobial properties against specific bacteria for the antibiotic-containing scaffolds. Only the 25 wt% CIP-containing scaffolds were cytotoxic. Collectively, this study suggests that polymer-based antibiotic-containing electrospun scaffolds could function as a biologically safe antimicrobial drug delivery system for regenerative endodontics.
  • Thumbnail Image
    Item
    Nicotine-Treated Fusobacterium nucleatum Binding to Collagen, Fibrinogen, and Fibronectin
    (Office of the Vice Chancellor for Research, 2016-04-08) Beshay, Y.S.; Gregory, R.L.
    Fusobacterium nucleatum, a gram-negative anaerobic bacterium found in dental plaque, causes periodontal diseases. Smoking is one of the risk factors that can increase periodontal problems and atherosclerosis. Atherosclerosis is initiated by oral bacteria (i.e., F. nucleatum) binding to surface proteins of endothelial cells, such as collagen, fibrinogen, and fibronectin. The main objective for this study was to test the binding of F. nucleatum to collagen, fibrinogen, and fibronectin under the effect of different concentrations of nicotine. F. nucleatum was grown overnight in brain-heart infusion (BHI) supplemented with yeast extract and 5% vitamin-K/hemin. Biofilm was grown for 48 hours in 0, 0.25, 0.5, 1, and 2 mg/mL of nicotine. Then, the biofilm cells were labeled with biotin 3-sulfo-N-hydroxy-succinimide ester sodium salt and fixed with 10% formaldehyde. A binding assay was conducted by coating a high-binding 96-well microtiter plate with 1 μg/mL of collagen, fibrinogen, or fibronectin. The plate was incubated overnight and blocked with 1% Bovine Serum Albumin (BSA), followed by the biotinylated and nicotine-treated F. nucleatum cells. ExtrAvidin-Peroxidase and OPD Peroxidase Substrate was used to visualize the binding. Optical density (OD) was measured with a spectrophotometer at 490 nm. Collagen, fibrinogen, and fibronectin binding assays demonstrated significantly higher absorbance with 2 mg/mL nicotine-treated F. nucleatum cells compared to untreated cells. The results indicated that an increase in nicotine concentration leads to an increase in F. nucleatum binding to collagen, fibrinogen, and fibronectin. This means that smokers may have an increased risk for atherosclerosis. Supported by Life-Health and Sciences Internship (LHSI).