Bimix Antimicrobial Scaffolds for Regenerative Endodontics

Abstract

Introduction Eliminating and/or inhibiting bacterial growth within the root canal system have been shown to play a key role in the regenerative outcome. The aim of this study was to synthesize and determine in vitro both the antimicrobial effectiveness and cytocompatibility of bi-mix antibiotic-containing polydioxanone (PDS)-based polymer scaffolds. Methods Antibiotic-containing (metronidazole, MET and ciprofloxacin, CIP) polymer solutions (distinct antibiotic weight ratios) were spun into fibers as a potential mimic to the double antibiotic paste (DAP, a MET/CIP mixture). Fiber morphology, chemical characteristics, and tensile strength were evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and tensile testing, respectively. Antimicrobial efficacy was tested over time (aliquot collection) against Enterococcus faecalis (Ef), Porphyromonas gingivalis (Pg), and Fusobacterium nucleatum (Fn). Similarly, cytotoxicity was evaluated in human dental pulp stem cells (hDPSCs). Data were statistically analyzed (p<0.05). Results SEM and FTIR confirmed that electrospinning was able to produce antibiotic-containing fibers with diameter mostly in the nanoscale. Tensile strength of 1:1MET/CIP scaffolds was significantly (p<0.05) higher than pure PDS (control). Meanwhile, all other groups presented similar strength as the control. Aliquots obtained from antibiotic-containing scaffolds inhibited growth of Ef, Pg and Fn, except pure MET that did not show an inhibitory action towards Pg or Fn. Antibiotic-containing aliquots promoted slight hDPSCs viability reduction, but none of them were considered to be cytotoxic. Conclusion Our data suggest that the incorporation of multiple antibiotics within a nanofibrous scaffold holds great potential towards the development of a drug delivery system for regenerative endodontics.

Development and characterization of novel ZnO-loaded electrospun membranes for periodontal regeneration

“…The electrospinning system used in this work consisted of a high-voltage source (ES50P-10W/DAM, Gamma High-Voltage Research Inc., Ormond Beach, FL, USA), a syringe pump (Legato 200, KD Scientific Apparatus, Holliston, MA, USA), and a grounded stainless steel collecting drum connected to a high-speed mechanical stirrer (BDC6015, Caframo, Wiarton, ON, Canada), and was described in detail elsewhere [6, 32, 33]. Processing parameters, including solution concentration, field strength, and flow rate were optimized for the distinct polymer systems to obtain defect-free fibrous membranes.…”

“…Porphyromonas gingivalis ( Pg ) (ATCC 33277) and Fusobacterium nucleatum ( Fn ) (ATCC 25586) using agar diffusion assays (n=3/group/bacteria) [33]. Bacteria were cultivated in Brain Heart Infusion (BHI) broth supplemented with 5 g yeast extract/L and 5% v/v vitamin K+ hemin (BHI-YE; Becton, Dickinson and Company) at 37°C in an anaerobic GasPak jar for 24 h [33]. Before testing, the minimum inhibitory concentration (MIC) of ZnO was determined using suspensions of ZnO nanoparticles in PBS at the following concentrations: 100, 250, 500, 1,000, 2,500, 5,000, and 10,000 µg/mL.…”

“…Before testing, the minimum inhibitory concentration (MIC) of ZnO was determined using suspensions of ZnO nanoparticles in PBS at the following concentrations: 100, 250, 500, 1,000, 2,500, 5,000, and 10,000 µg/mL. In brief, 10 µL of each suspension was dropped on cultured blood agar plates containing the bacterial lawns, and the inhibition zones (in mm) were measured after 5 days of incubation [33]. For the antibacterial activity of the membranes, disk-shaped samples (5-mm in diameter) were prepared and sterilized through ultraviolet (UV) irradiation for 1 h (30 min each side), before placing on the cultured blood agar plates as previously indicated [33, 34].…”

Tissue-engineering-based Strategies for Regenerative Endodontics

“…However, recent findings have shown that antibiotic pastes at clinically advocated concentrations affect the survivability of SCAPs (Ruparel et al, 2012). Thus, as a potentially more cell-friendly disinfection strategy, antibiotic-containing polymer nanofibers capable of acting as a drug delivery system and eliminating root canal infection have been developed (Bottino et al, 2013(Bottino et al, , 2014aPalasuk et al, 2014).…”

“…1A) may minimize these adverse effects and yet still promote the elimination of bacteria (Bottino et al, 2013(Bottino et al, , 2014aPalasuk et al, 2014). Analysis of high-performance liquid chromatography (HPLC) data, in addition to cell toxicity experiments, has supported the claim of a more biologically friendly strategy when compared with the use of antibiotic pastes, since the quantity of drug(s) released occurs more gradually in a lower concentration than in those used in pastes (Bottino et al, 2013(Bottino et al, , 2014aPalasuk et al, 2014). Meanwhile, lower concentrations of antibiotics demonstrate antimicrobial action against Porphyromonas gingivalis and Enterococcus faecalis biofilms (Bottino et al, 2013).…”