Nanoparticle-based endodontic antimicrobial photodynamic therapy.
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.
Pagonis
Tom C
TC
Advanced Graduate Endodontics, Division of Endodontics, Harvard School of Dental Medicine, Boston, Massachusetts, USA.
Chen
Judy
J
Fontana
Carla Raquel
CR
Devalapally
Harikrishna
H
Ruggiero
Karriann
K
Song
Xiaoqing
X
Foschi
Federico
F
Dunham
Joshua
J
Skobe
Ziedonis
Z
Yamazaki
Hajime
H
Kent
Ralph
R
Tanner
Anne C R
AC
Amiji
Mansoor M
MM
Soukos
Nikolaos S
NS
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
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