Phototoxic effect of curcumin on methicillin-resistant Staphylococcus aureus and L929 fibroblasts

Photodynamic therapy has been investigated as an alternative method of killing pathogens in response to the multiantibiotic resistance problem. This study evaluated the photodynamic effect of curcumin on methicillin-resistant Staphylococcus aureus (MRSA) compared to susceptible S. aureus (MSSA) and L929 fibroblasts. Suspensions of MSSA and MRSA were treated with different concentrations of curcumin and exposed to light-emitting diode (LED). Serial dilutions were obtained from each sample, and colony counts were quantified. For fibroblasts, the cell viability subsequent to the curcumin-mediated photodynamic therapy was evaluated using the MTT assay and morphological changes were assessed by SEM analysis. Curcumin concentrations ranging from 5.0 to 20.0 μM in combination with any tested LED fluences resulted in photokilling of MSSA. However, only the 20.0 μM concentration in combination with highest fluence resulted in photokilling of MRSA. This combination also promoted an 80% reduction in fibroblast cell metabolism and morphological changes were present, indicating that cell membrane was the main target of this phototherapy. The combination of curcumin with LED light caused photokilling of both S. aureus strains and may represent an alternative treatment for eradicating MRSA, responsible for significantly higher morbidity and mortality and increased healthcare costs in institutions and hospitals. © 2012 Springer-Verlag London Ltd.

Effect of different pre-irradiation times on curcumin-mediated photodynamic therapy against planktonic cultures and biofilms of Candida spp

Objectives: The aim of this study was to evaluate the effects of pre-irradiation time (PIT) on curcumin (Cur)-mediated photodynamic therapy (PDT) against planktonic and biofilm cultures of reference strains of Candida albicans, Candida glabrata and Candida dubliniensis. Materials and methods: Suspensions and biofilms of Candida species were maintained in contact with different concentrations of Cur for time intervals of 1, 5, 10 and 20 min before irradiation and LED (light emitting diode) activation. Additional samples were treated only with Cur, without illumination, or only with light, without Cur. Control samples received neither light nor Cur. After PDT, suspensions were plated on Sabouraud Dextrose Agar, while biofilm results were obtained using the XTT-salt reduction method. Confocal Laser Scanning Microscopy (CLSM) observations were performed to supply a better understanding of Cur penetration through the biofilms after 5 and 20 min of contact with the cultures. Results: Different PITs showed no statistical differences in Cur-mediated PDT of Candida spp. cell suspensions. There was complete inactivation of the three Candida species with the association of 20.0 μM Cur after 5, 10 and 20 min of PIT. Biofilm cultures showed significant reduction in cell viability after PDT. In general, the three Candida species evaluated in this study suffered higher reductions in cell viability with the association of 40.0 μM Cur and 20 min of PIT. Additionally, CLSM observations showed different intensities of fluorescence emissions after 5 and 20 min of incubation. Conclusion: Photoinactivation of planktonic cultures was not PIT-dependent. PIT-dependence of the biofilm cultures differed among the species evaluated. Also, CLSM observations confirmed the need of higher time intervals for the Cur to penetrate biofilm structures. © 2012 Elsevier Ltd. All rights reserved.

Photodynamic inactivation of Streptococcus mutans and Streptococcus sanguinis biofilms in vitro

The purpose of this study was to evaluate specific effects of photodynamic inactivation (PDI) using erythrosine (ER) and Rose Bengal (RB) photosensitizers and a blue light-emitting diode (LED) on the viability of Streptococcus mutans and Streptococcus sanguinis biofilms. Biofilms were grown in acrylic disks immersed in broth to production of biofilms, inoculated with microbial suspension (106 cells/mL) and incubated for 48 h. After the formation of biofilms, the effects of the photosensitizers ER and RB at a concentration of 5 μM for 5 min and blue LED (455 ± 20 nm) for 180 s, photosensitizers alone and conjugated were evaluated. Next, the disks were placed in tubes with sterile physiological solution (0.9 % sodium chloride) and sonicated for to disperse the biofilms. Tenfold serial dilutions were carried and aliquots seeded in brain heart infusion agar which were then incubated for 48 h. Then the numbers colony-forming units per milliliter (CFU/mL; log 10) were counted and analyzed statistically (ANOVA, Tukey test, P ≤ 0.05). Significant decreases in the viability of all microorganisms were observed for biofilms exposed to PDI mediated by both photosensitizers. The reductions with RB and ER were, 0.62 and 0.52 log10 CFU mL -1 for S. mutans biofilms (p = 0.001), and 0.95 and 0.88 log 10 CFU mL-1 for S. sanguinis biofilms (p = 0.001), respectively. The results showed that biofilms formed in vitro by S. mutans and S. sanguinis, were sensitive to PDI using a blue LED associated with photosensitizers ER or RB, indicating its use in the control of caries and periodontal diseases. © 2012 Springer-Verlag London Ltd.

Susceptibility of multispecies biofilm to photodynamic therapy using Photodithazine®

This in vitro study evaluated the effect of photodynamic therapy (PDT) on the multispecies biofilm of Candida albicans, Candida glabrata, and Streptococcus mutans. Standardized fungal and bacterial suspensions were cultivated appropriately for each species and inoculated in 96-well microtiter plates for mix-biofilm formation. After 48 h of incubation, the biofilms were submitted to PDT (P + L+) using Photodithazine® (PDZ) at 100, 150, 175, 200, or 250 mg/mL for 20 min and 37.5 J/cm2 of light-emitting diode (LED) (660 nm). Additional samples were treated only with PDZ (P + L-) or LED (P-L+), or neither (control, P-L-). Afterwards, the biofilms were evaluated by quantification of colonies (CFU/mL), metabolic activity (XTT reduction assay), total biomass (crystal violet staining), and confocal scanning laser microscopy (CSLM). Data were analyzed by one-way ANOVA and Tukey tests (p < 0.05). Compared with the control, PDT promoted a significant reduction in colonies viability of the three species evaluated with 175 and 200 mg/mL of PDZ. PDT also significantly reduced the metabolic activity of the biofilms compared with the control, despite the PDZ concentration. However, no significant difference was found in the total biomass of samples submitted or not to PDT. For all analysis, no significant difference was verified among P-L-, P + L-, and P-L+. CSLM showed a visual increase of dead cells after PDT. PDT-mediated PDZ was effective in reducing the cell viability of multispecies biofilm. © 2013 Springer-Verlag London.

Comparison of the effect of rose bengal- and eosin Y-mediated photodynamic inactivation on planktonic cells and biofilms of Candida albicans

Candida albicans is an opportunistic yeast that can cause oral candidosis through the formation of a biofilm, an important virulence factor that compromises the action of antifungal agents. The objective of this study was to compare the effect of rose bengal (RB)- and eosin Y (EY)-mediated photodynamic inactivation (PDI) using a green light-emitting diode (LED; 532 ± 10 nm) on planktonic cells and biofilms of C. albicans (ATCC 18804). Planktonic cultures were treated with photosensitizers at concentrations ranging from 0.78 to 400 μM, and biofilms were treated with 200 μM of photosensitizers. The number of colony-forming unit per milliliter (CFU/mL) was compared by analysis of variance and Tukey's test (P ≤ 0.05). After treatment, one biofilm specimen of the control and PDI groups were examined by scanning electron microscopy. The photosensitizers (6.25, 25, 50, 200, and 400 μM of EY, and 6.25 μM of RB or higher) significantly reduced the number of CFU/mL in the PDI groups when compared to the control group. With respect to biofilm formation, RB- and EY-mediated PDI promoted reductions of 0.22 log10 and 0.45 log10, respectively. Scanning electron microscopy showed that the two photosensitizers reduced fungal structures. In conclusion, EY- and RB-mediated PDI using LED irradiation significantly reduced C. albicans planktonic cells and biofilms. © 2013 Springer-Verlag London.

Photodynamic inactivation of clinical isolates of Candida using Photodithazine

This study evaluated the photodynamic inactivation (PDI) mediated by Photodithazine® (PDZ) against 15 clinical isolates of Candida albicans, Candida glabrata and Candida tropicalis. Each isolate, in planktonic and biofilm form, was exposed to PDI by assessing a range of PDZ concentrations and light emitting diode fluences. Cell survival of the planktonic suspensions was determined by colony forming units (CFU ml-1). The antifungal effects of PDI against biofilms were evaluated by CFU ml-1 and metabolic assay. Data were analyzed by non-parametric tests (α = 0.05). Regardless of the species, PDI promoted a significant viability reduction of planktonic yeasts. The highest reduction in cell viability of the biofilms was equivalent to 0.9 log10 (CFU ml-1) for C. albicans, while 1.4 and 1.5 log10 reductions were obtained for C. tropicalis and C. glabrata, respectively. PDI reduced the metabolic activity of biofilms by 62.1, 76.0, and 76.9% for C. albicans, C. tropicalis, and C. glabrata, respectively. PDZ-mediated PDI promoted significant reduction in the viability of Candida isolates. © 2013 Taylor & Francis.

Prevenção da contaminação cruzada em odontologia por meio de terapia fotodinâmica (TFD) utilizando LED azul e curcumina

Pós-graduação em Odontologia - FOAR

Avaliação de LEDs de alta intensidade quanto à eficiência de polimerização de resina composta e variação de temperatura na dentina bovina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento e caracterização de dispositivos luminescentes híbridos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo das propriedades elétro-óptica de dispositivos eletroluminescentes confeccionados com um compósito híbrido

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Terapia fotodinâmica em esporos de bacillus atrophaeus e bacillus subtilis: estudos com LASER, LED, azul de metileno, rosa bengala e verde malaquita

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da terapia fotodinâmica em candida albicans in vitro e in vivo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biofilmes heterotípicos formados por C.albicans e espécies não albicans: estudo da interação microbiana e da sensibilidade à terapia fotodinâmica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efetividade da terapia fotodinâmica mediada pela curcumina em Candida spp

Pós-graduação em Reabilitação Oral - FOAR

Ressonância paramagnética eletrônica (RPE) aplicada em semicondutores orgânicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)