A Babeer
| A Babeer |
Alaa Babeer1, Yuan Liu2, Zhi Ren3, Min Jun Oh3 Hyun Koo3
1Endodontics, University of Pennsylvania, School of Dental Medicine ; 2Preventive and Restorative Sciences, University of Pennsylvania; 3Orthodontics, University of Pennsylvania, School of Dental Medicine
Introduction
Iron-oxide nanoparticles (IONP) exhibit high catalytic activity that is similar to natural peroxidase, which has shown therapeutic activity including prevention of tumors and infections. Many infectious diseases are caused by and associated with biofilms, including endodontic infections. The reduction or elimination of microorganisms has been associated with positive endodontic outcomes and is the basis for prevention and treatment of endodontic pathology. However, conventional irrigants fail to completely eliminate bacterial biofilm within the root canal system. Therefore, we assessed the potential of IONP/ H2O2 system as a potent antimicrobial agent against Enterococcus faecalis alone and in multispecies biofilm via its intrinsic catalytic activity.
Methods
The catalytic properties of IONP were characterized. The catalytic activity of bacteria-bound IONP was also assessed via colorimetric analysis. The antimicrobial effect of the IONP/H2O2 system against actively growing E. faecalis OG1RF, was assessed in a dose-and time-dependent manner. Antimicrobial efficacy was assessed via biochemical/microbiological methods. Mono- and multi-species E. faecalis biofilm (including Fusobacterium nucleatum, and Streptococcus gordonii ) formed on in vitro vertically positioned apatitic surfaces and ex vivo extracted teeth model were treated with IONP/H2O2 in a dose- and time-dependent fashion. Antibiofilm activity was assessed via biochemical/microbiological and fluorescence-based methods.
Results
The data revealed that IONP rapidly catalyzed H2O2 to generate reactive oxygen species (ROS) in a dose dependent fashion. Interestingly, IONP bound to bacterial cells retained their intrinsic catalytic activity and rapidly catalyzed H2O2 to generate ROS suggesting the mechanism for the antimicrobial killing. The antimicrobial and antibiofilm bacterial killing effect of the IONP/H2O2 followed a dose- and time-dependent trends (6mg/ml IONP/H2O2 achieved reduction of viable cells below detection limit within 5 minutes and 10 minutes planktonic and biofilm Enterococcus faecalis respectively). IONP/H2O2 performed better than NaOCl in reducing the number of viable cells in ex vivo biofilm.
Conclusion
Our results indicate the potential to exploit Iron oxide nanoparticles with intrinsic catalytic activity as a potent alternative or adjunctive antimicrobial agent for the treatment of endodontic infections.