Showing papers by "Maria A. F. Faustino published in 2017"

Antimicrobial Photodynamic Therapy against Endodontic Enterococcus faecalis and Candida albicans Mono and Mixed Biofilms in the Presence of Photosensitizers: A Comparative Study with Classical Endodontic Irrigants.

Abstract: Endodontic biofilms eradication from the infected root canal system remains as the primary focus in endodontic field. In this study it was assessed the efficacy of antimicrobial Photodynamic Therapy (aPDT) with the Zn(II)chlorin e6 methyl ester (Zn(II)e6Me) activated by red light against monospecies and mixed biofilms of Enterococcus faecalis and Candida albicans. The results were compared with the ones obtained with Rose Bengal (RB), Toluidine Blue-O (TBO), the synthetic tetracationic porphyrin (TMPyP) as well as classical endodontic irrigants (3% NaOCl, 17% EDTA and 2% CHX). The antimicrobial efficacy of aPDT towards monospecies and mixed biofilms was quantified resorting to safranin red method. The changes of biofilm organization and of cellular ultrastructure were evaluated through several microscopy techniques (light, laser confocal and transmission electron microscopy). Zn(II)e6Me once activated with light for 60 or 90 s was able to remove around 60% of the biofilm’s biomass. It was more efficient than TBO and RB and showed similar efficiency to TMPyP and classical irrigants, CHX and EDTA. As desirable in a PS, Zn(II)e6Me in the dark showed smaller activity than TMPyP. Only NaOCl revealed higher efficiency, with 70-90% of the biofilm’s biomass removal. The organization of biofilms and the normal microbial cell ultrastructure were extensively damaged by the presence of Zn(II)e6Me. aPDT with Zn(II)e6Me showed to be an efficient antimicrobial strategy deserving further studies leading to a future clinical usage in endodontic disinfection.

Photodynamic Action against Wastewater Microorganisms and Chemical Pollutants: An Effective Approach with Low Environmental Impact

Abstract: Wastewater (WW) from urban and industrial activities is often contaminated with microorganisms and chemical pollutants. To reduce the concentration of microorganisms in WW to levels comparable to those found in natural waters, the sewage effluent is usually subjected to disinfection with chlorine, ozone, or ultraviolet light, which may lead to the formation of toxic products and contribute to the selection of resistant genes. Moreover, the changing patterns of infectious diseases and the emerging of multidrug resistant microbial strains entail the development of new technologies for WW decontamination. Microbial photodynamic inactivation (PDI) with photosensitizers, oxygen, and visible light has demonstrated to be effective in the inactivation of microorganisms via photogeneration of reactive oxygen species able to induce microbial damage at the external structures level. The promising results of PDI suggest that this principle can be applied to WW treatment to inactivate microorganisms but also to photodegrade chemical pollutants. The aim of this study was to assess the applicability of PDI for the microbial and chemical decontamination of secondarily treated WW. To evaluate the efficiency of bacterial inactivation in WW, experiments were done in both phosphate buffer saline (PBS) and filtered WW with the bioluminescent Escherichia coli, using small and large volumes of WW. The potential of PDI to inactivate the native bacteria (E. coli and Enterococcus) present in WW was tested and assays without the adding of bacteria to the WW were performed. It was also tested if the same PDI protocol was able to induce phototransformation of phenol. The cationic porphyrin 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetra-iodide (Tetra-Py+-Me) was shown to be effective against both bacterial groups representing both Gram-negative and Gram-positive bacteria used as microbiological parameters to instigate water quality and even showing the power to photooxidate organic compounds. As the photosensitizer when immobilized on solid matrixes can be easily removed, recovered, and reused, an effective, less-expensive, easy-applicable, and environmentally friendly technology can be applied to treat WW, inactivating microorganisms and degrading chemical contaminants at the same time.

A ruthenium(II)-trithiacyclononane curcuminate complex: synthesis, characterization, DNA-interaction, and cytotoxic activity

Abstract: The coordination of ruthenium(II) complexes to anionic oxygen-based donors are very rare. This study describes a simple, one-pot method for obtaining [ruthenium(II)(trithiacyclononane)(curcumin)(S-DMSO)]Cl (1) in 37% yield. The structural characterization of complex 1 by elemental analysis, FT-IR, 1-D and 2-D NMR, ESI+-MS as well as UV–vis and fluorescence spectroscopies are presented. The DNA-melting temperature (Tm) assay shows that salmon sperm DNA (smDNA) in the presence of complex 1 has a higher melting temperature, with ΔTm = 7.4 °C, while in the presence of curcumin the melting temperature remains unaltered. The in vitro cytotoxic activities of curcumin and complex 1 were investigated using the tumor human prostate cell line, PC-3, and the healthy cell line, PNT-2. Complex 1 is innocuous toward normal prostate epithelial cells and, whereas curcumin is toxic, with inhibition rates of ca. 35 and 65% at 50 and 80 μM, respectively. On the tumor cell line PC-3, complex 1 did not cause viability ...