Efficacy of antimicrobial photodynamic therapy administered using methylene blue, toluidine blue and tetra 2-mercaptopyridine substituted zinc phthalocyanine in root canals contaminated with Enterococcusaecalis.

BACKGROUND: Traditional chemomechanical treatment procedures are an indispensable part of endodontic treatment, however, additional treatment approaches such as antimicrobial photodynamic therapy (aPDT) may also be recommended for the elimination of residual microorganisms. In this study, the disinfection efficiency of aPDT performed using methylene blue (MB), toluidine blue (TB), and tetra 2-mercaptopyridine substituted zinc phthalocyanine (TM-ZnPc) was compared in the roots contaminated with Enterococcus faecalis (E. faecalis). MATERIALS AND METHODS: Forty-nine teeth with a single root and canal were included in this study. The roots were sterilized, and inoculated with E. faecalis. The roots were kept in an incubator for 30 days to form the biofilm. Forty-five teeth were prepared up to the F3 file of the ProTaperNext system under 2.5 % NaOCL irrigation. The samples were divided into three groups according to the type of used photosensitizer (PS) (n = 15); MB (313 µM), TB (327 µM), and TM-ZnPc (6µM). All PSs were irradiation with a light-emitting diode (LED) lamp (630 nm, 2-4 mW/cm²) for the 60 s. Two microbiological samples of the intracanal content were taken (one before and one immediately after additional aPDT in all groups) using sterile paper points. The colony-forming units per milliliter (CFU/mL) were calculated after 24 h of incubation at 37 °C. RESULTS: After all aPDT protocols, intracanal bacterial load decreased significantly compared to the amount after chemomechanical preparation (P < 0.05). No significant difference in the reduction in intracanal bacterial load was found between the PSs (P < 0.05). CONCLUSIONS: In the current study, the aPDT protocol performed with TM-ZnPc provided similar antimicrobial efficacy, although it was used at a lower concentration compared to MB and TB. Therefore, the use of TM-ZnPc in intra-canal disinfection in endodontics seems promising.

Impact of water-soluble zwitterionic Zn(II) phthalocyanines against pathogenic bacteria.

The photodynamic impact of water-soluble zwitterionic zinc phthalocyanines (ZnPc1-4) was studied on pathogenic bacterial strains after specific light exposure (LED 665 nm). The structural differences between the studied ZnPc1-4 are in the positions and the numbers of substitution groups as well as in the bridging atoms (sulfur or oxygen) between substituents and macrocycle. The three peripherally substituted compounds (ZnPc1-3) are tetra-2-(N-propanesulfonic acid)oxypyridine (ZnPc1), tetra-2-(N-propanesulfonic acid)mercaptopyridine (ZnPc2), and octa-substituted 2-(N-propanesulfonic acid)mercaptopyridine (ZnPc3). The nonperipherally substituted compound is tetra-2-(N-propanesulfonic acid)mercaptopyridine (ZnPc4). The uptake and localization capability are studied on Gram (+) Enterococcus faecalis and Gram (-) Pseudomonas aeruginosa as suspensions and as 48 h biofilms. Relatively high accumulations of ZnPc1-4 show bacteria in suspensions with different cell density. The compounds have complete penetration in E. faecalis biofilms but with nonhomogenous distribution in P. aeruginosa biomass. The cytotoxicity test (Balb/c 3T3 Neutral Red Uptake) with ZnPc1-4 suggests the lack of dark toxicity on normal cells. However, only ZnPc3 has a minimal photocytotoxic effect toward Balb/c 3T3 cells and a comparable high potential in the photoinactivation of pathogenic bacterial species.

A first archetype of boron dipyrromethene-phthalocyanine pentad dye: design, synthesis, and photophysical and photochemical properties.

A novel type of phthalocyanine pentad containing four boron dipyrromethene (BODIPY) units at peripheral positions of the phthalocyanine framework has been designed and synthesized for the first time. The Sonogashira coupling reaction between 4,4'-difluoro-8-(4-ethynyl)-phenyl-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (Ethynyl-BODIPY) and 2(3),9(10),16(17),23(24)-tetrakis(iodo) zinc(ii) phthalocyanine (Iodo-Pc) has been used for the synthesis of the target compound. The BODIPY-phthalocyanine pentad dye (BODIPY-Pc) has been fully characterized by (1)H NMR, MALDI-TOF mass, FT-IR and UV-Vis spectroscopic techniques and elemental analysis as well. The photoinduced energy transfer process for this dye system was explored in tetrahydrofuran solution. The singlet oxygen generation capability and photodegradation behaviours of this BODIPY-Pc pentad dye were also investigated in DMSO for the determination of the usability of this new type of dye system as a photosensitizer in PDT applications.