title: Nanoparticle-based endodontic antimicrobial photodynamic therapy.
abstract: OBJECTIVE
  To study the in vitro effects of poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with the photosensitizer methylene blue (MB) and light against Enterococcus faecalis (ATCC 29212).
  
  
  METHODS
  The uptake and distribution of nanoparticles in E. faecalis in suspension was investigated by transmission electron microscopy (TEM) after incubation with PLGA complexed with colloidal gold particles for 2.5, 5, and 10 minutes. E. faecalis species were sensitized in planktonic phase and in experimentally infected root canals of human extracted teeth with MB-loaded nanoparticles for 10 minutes followed by exposure to red light at 665 nm.
  
  
  RESULTS
  The nanoparticles were found to be concentrated mainly on the cell walls of microorganisms at all three time points. The synergism of light and MB-loaded nanoparticles led to approximately 2 and 1 log10 reduction of colony-forming units (CFUs) in planktonic phase and root canals, respectively. In both cases, mean log10 CFU levels were significantly lower than controls and MB-loaded nanoparticles without light.
  
  
  CONCLUSIONS
  The utilization of PLGA nanoparticles encapsulated with photoactive drugs may be a promising adjunct in antimicrobial endodontic treatment.
authors.affiliation: Advanced Graduate Endodontics, Division of Endodontics, Harvard School of Dental Medicine, Boston, Massachusetts, USA.
authors.forename: Tom C
authors.initials: TC
authors.lastname: Pagonis
authors.forename: Judy
authors.initials: J
authors.lastname: Chen
authors.forename: Carla Raquel
authors.initials: CR
authors.lastname: Fontana
authors.forename: Harikrishna
authors.initials: H
authors.lastname: Devalapally
authors.forename: Karriann
authors.initials: K
authors.lastname: Ruggiero
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Song
authors.forename: Federico
authors.initials: F
authors.lastname: Foschi
authors.forename: Joshua
authors.initials: J
authors.lastname: Dunham
authors.forename: Ziedonis
authors.initials: Z
authors.lastname: Skobe
authors.forename: Hajime
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Ralph
authors.initials: R
authors.lastname: Kent
authors.forename: Anne C R
authors.initials: AC
authors.lastname: Tanner
authors.forename: Mansoor M
authors.initials: MM
authors.lastname: Amiji
authors.forename: Nikolaos S
authors.initials: NS
authors.lastname: Soukos
mesh_terms: D000891:Anti-Infective Agents, Local / Q000008:administration & dosage* / Q000737:chemistry; D015169:Colony Count, Microbial; D003786:Dental Pulp Cavity / Q000382:microbiology; D004203:Disinfection / Q000379:methods; D004337:Drug Carriers / Q000008:administration & dosage / Q000737:chemistry; D013293:Enterococcus faecalis / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure; D006801:Humans; D019344:Lactic Acid / Q000008:administration & dosage* / Q000737:chemistry; D008751:Methylene Blue / Q000008:administration & dosage* / Q000737:chemistry; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry / Q000648:ultrastructure; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage* / Q000737:chemistry; D011100:Polyglycolic Acid / Q000008:administration & dosage* / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer
chemical_list: D000891:Anti-Infective Agents, Local; D004337:Drug Carriers; D017319:Photosensitizing Agents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D008751:Methylene Blue