Erythrosine Research Articles

Double-wavelength overlapping resonance Rayleigh scattering technique for the simultaneous quantitative analysis of three β-adrenergic blockade

Four simple and accurate spectrophotometric methods were proposed for the simultaneous determination of three β-adrenergic blockade, e.g. atenolol, metoprolol and propranolol. The methods were based on the reaction of the three drugs with erythrosine B (EB) in a Britton–Robinson buffer solution at pH4.6. EB could combine with the drugs to form three ion-association complexes, which resulted in the resonance Rayleigh scattering (RRS) intensity that is enhanced significantly with new RRS peaks that appeared at 337nm and 370nm, respectively. In addition, the fluorescence intensity of EB was also quenched. The enhanced scattering intensities of the two peaks and the fluorescence quenched intensity of EB were proportional to the concentrations of the drugs, respectively. What is more, the RRS intensity overlapped with the double-wavelength of 337nm and 370nm (so short for DW-RRS) was also proportional to the drugs concentrations. So, a new method with highly sensitive for simultaneous determination of three bisoprolol drugs was established. Finally, the optimum reaction conditions, influencing factors and spectral enhanced mechanism were investigated. The new DW-RRS method has been applied to simultaneously detect the three β-blockers in fresh serum with satisfactory results.

Erythrosine-Mediated Photodynamic Inactivation of Bacteria and Yeast Using Green Light-Emitting Diode Light

Erythrosine, also known as FD & C Red No. 3, is a synthetic dye that has been used for food coloring and dental plaque detection. The objective of this study was to evaluate erythrosine as a viable photosensitizer in photodynamic inactivation (PDI) of bacteria and yeast. Cells were treated with erythrosine with or without acetic acid in the presence and absence of light. Erythrosine in the absence of light did not show any activity against the microorganisms. When treated with light, erythrosine was efficient in eradicating non-adherent (planktonic) Gram (+) bacteria and yeast. However, Gram (-) bacteria were less responsive to PDI. Addition of acetic acid was found to enhance the activity of erythrosine and significantly lower the survival of Gram (-) bacteria. This study demonstrated the potential applications of erythrosine in PDI and the potentiating effects of acetic acid.

Removal of erythrosine dye from aqueous solutions using magnetic chitosan with erythrosine as imprinted molecules

A novel, chitosan coating on the surface of magnetite (Fe3O4) (erythrosine-imprinted magnetic chitosan (EIMC)) was successfully synthesized using erythrosine (ER) as a template for adsorption and the removal of ER from aqueous solutions. Characterization of the obtained EIMC was achieved by FTIR spectra, SEM micrographs, and TGA analysis. Batch adsorption experiments of EIMC and non-imprinted magnetic chitosan (NIMC) were performed to investigate the adsorption conditions. The results showed that the maximum adsorption capacity for EIMC and NIMC was observed at pH 6 and temperature 40°C. Equilibrium adsorption was achieved within 3 h. Adsorption process could be well described by Freundlich adsorption isotherms. Thermodynamic parameters namely ΔG°, ΔH°, and ΔS° of the ER adsorption process were calculated. The negative values of Gibbs free energy of adsorption (ΔG°) indicated the spontaneity of the adsorption of ER dye on the EIMC and NIMC. Desorption of ER from EIMC and NIMC could be done rapidly using 0.1 M NaOH solution and the beads could be used again to remove ER. Results show that imprinting technique increases the removal amount of ER dye from aqueous solutions.

Photodynamic Inactivation Mediated by Erythrosine and its Derivatives on Foodborne Pathogens and Spoilage Bacteria.

The purpose of the present study was to evaluate the efficacy of photodynamic inactivation (PDI) mediated by erythrosine (ERY) and its ester derivatives erythrosine methyl ester (ERYMET) and erythrosine butyl ester (ERYBUT) on foodborne pathogens and spoilage bacteria. We evaluated Staphylococcus aureus ATCC 25923, Aeromonas hydrophila ATCC 7966, Salmonella enterica serotype Typhimurium ATCC 14028, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853. The toxicity of all of the compounds was assessed in VERO cells. PDI mediated by ERY and its derivatives combined with a light-emitting diode was performed at different concentrations and exposure times. S. aureus was more photosensitive than Gram-negative bacteria to ERY, ERYMET, and ERYBUT. The ERY-mediated PDI of S. aureus induced a significant reduction of 4.0 log CFU/ml at a light dose of 40J/cm(2). ERYMET and ERYBUT at lower light doses than ERY completely eradicated S. aureus. When photoirradiated with ERY at light doses of 156 and 234J/cm(2), A. hydrophila was completely eradicated. ERYBUT was more efficient in the PDI of A. hydrophila than ERYMET, even at 1x10(-5) M and lower light doses. Salmonella Typhimurium, E. coli, and P. aeruginosa required higher concentrations of photosensitizers to reduce cell survival. ERYBUT and ERY may be promising photosensitizing agents against A. hydrophila and S. aureus. They were effective at reducing bacterial counts at nontoxic concentrations. The photoinactivation rate of the evaluated bacteria decreased in the following order: S. aureus>A. hydrophila>E. coli>S. Typhimurium>P. aeruginosa.

The accessibility of a unimolecular micelle's core to environmental ions: Exploration with a xanthene dye

ABSTRACTTo learn the impact of aqueous environmental species on the property of the isolated core of a water‐soluble unimolecular micelle (UIM), a guest dye of erythrosine B (EB) is used as a probe to map the dynamic microenvironment of the UIM. PEGylation of branched polyethylenimine (PEI) with oxirane‐functionalized polyethylene glycol (PEG) leads to a UIM of PEI@PEG, and the core is further chemically engineered. The resulting UIMs can irreversibly encapsulate EB exclusively by the core. It is found that the stacking of EB molecules is dependent on the electronic microenvironment of the UIMs, where a polar and ionic core favors a twist stacking of EB, but a less polar core results in an unprecedented parallel stacking of EB. Spectral analysis shows that EB is encapsulated along with its counter ion of Na+, and an exterior ion can cause dehydration of the UIMs but can hardly enter the UIMs; moreover, ion exchange through the PEG shell is actually allowed. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 566–573

Simultaneous Determination of Acetaminophen and Synthetic Color(s) by Derivative Spectroscopy in Syrup Formulations and Validation by HPLC: Exposure Risk of Colors to Children.

Color additives are used in pediatric syrup formulations as an excipient; though not pre-requisite, but pediatric syrup formulations are normally colored. An attempt has been made to measure simultaneously the single drug, acetaminophen (AT), along with the colors, carmoisine (CA), erythrosine (ET), and sunset yellow FCF (SSY) added in it by three derivative spectroscopy methods namely, 1st order, ratio, and differential derivative methods. Moreover, evaluation has been made for the exposure assessment of the colors added as excipient because some colors have been reported to cause allergic reactions and hypersensitivity in children. The present methods provide simple, accurate, and reproducible quantitative determination of the drug, AT, along with the color in synthetic mixtures and commercial drug formulations without any interference. The limit of detection varied from 0.0001-0.31 μg/ml while limit of quantification ranged from 0.002-1.04 μg/ml in all the three methods. The calibration curve of all the three derivative methods exhibited good linear relationship with excellent regression coefficients (0.9986-1.000). Both intra-day and inter-day precisions showed %RSD value less than 2% while the percentage recovery was found between 96.8-103.8%. The sensitivity of the proposed methods is almost comparable to HPLC and thus, can be used for determination of drug AT, and color simultaneously in pharmaceutical formulation on routine basis. The present methods also showed that colors like SSY and ET are saturating more than 50% of acceptable daily intake (ADI) value which is alarming and needs to be considered for modification by regulatory authorities to safeguard the health of children.

Three-dimensional extended nonlocal photopolymerization driven diffusion model Part I Absorption

When holographic gratings are recorded in a photopolymer material layer, the spatial distributions of the photoreactions taking place lead to the formation of nonuniform gratings in depth. In an effort to study such effects, in this series of papers a three-dimensional (3D) nonlocal photopolymerization driven diffusion (NPDD) model is developed. In Part I, we focused on describing the photoinitiation mechanisms by introducing a 3D dye absorption model that more accurately and physically describes the processes taking place. Then, the values of physical parameters are extracted by numerically fitting experimentally obtained normalized transmittance growth curves for a range of layer thicknesses in an acrylamide/polyvinyl alcohol (AA/PVA) photopolymer material sensitized by Erythrosine B (EB). In Part II [J. Opt. Soc. Am. B31, 2648 (2014)10.1364/JOSAB.31.002648JOBPDE0740-3224], applying the results in Part I, the full 3D photophysical and photochemical evolutions are modeled. Then the resulting 3D NPDD model is validated experimentally.

THE EVALUATION OF SINGLET OXYGEN QUENCHING AND SUNSCREEN ACTIVITY OF CORN COB EXTRACT

The corn cob waste has been reported to have antioxidant activity. Active compound such as antioxidant has been considered as potential sunscreen resources. The objectives of this research were to determine singlet oxygen quenching and sunscreen activity of corn cob. Corn cob was extracted using ethanol 20, 40, 60 and 80% by reflux for 2h at 78oC. The singlet oxygen quenching activity was evaluated by photooxidation of linoleic acid. Singlet oxygen quenching activity was conducted using linoleic acid as substrate containing erythrosine as a sensitizer and exposed under continuous illumination (4000 lux) with the fluorescent light for up to 5h. The sunscreen activity was evaluated by sun protection factor (SPF) using spectrophotometry UV-Vis. Ethanol extract 80% (E80) shows the highest total phenolic content followed with E60, E40 and E20. The result shows that the lowest singlet oxygen quenching activity was E20 (15.63%), and the highest was E80 by 65.63% percentage of inhibition. SPF value of E20, E40, E60, and E80 at concentration 200μg/mL were 7.52; 12.24; 15.81 and 17.78, respectively. SPF value increase with the increasing of concentration, total phenolic content and singlet oxygen quenching activity. The conclusion of this research was corn cob extract possess phytochemical compound having potency as singlet oxygen quencher and sunscreen active compound. Keywords: corn cob, phenolic phytochemical, singlet oxygen quenching, sunscreens

Adsorption Equilibrium and Kinetics of Toxic Dye-Erythrosine B Adsorption onto Montmorillonite

Erythrosine B is extensively used in the textile and food industry. It is reported to be a neurotoxicant and is carcinogenic in nature. It can induce DNA damage in the gastrointestinal organs even at low doses. In this study, adsorption efficiency of montmorillonite (MMT) has been investigated for the removal of erythrosine B (EB) from aqueous solution. The batch adsorption model was developed to predict the equilibrium adsorption capacity with respect to the pH of the dye solution, contact time, initial dye concentration, and adsorbent dosage. A maximum monolayer adsorption capacity of 578.03 mg/g was obtained at the original pH (7.5) of the aqueous dye solution within 5 minutes of contact time. It was found that the Langmuir adsorption isotherm yielded the most favorable representation of the adsorption behavior of EB. The dye was found to be chemisorbed on the adsorbent as confirmed by the FTIR spectral analysis. Although anionic in nature, the dye was found to be intercalated into the clay interlayers as suggested by the X-ray diffraction studies.

The promiscuous protein binding ability of erythrosine B studied by metachromasy (metachromasia)

The present study aims to elucidate aspects of the protein binding ability of erythrosine B (ErB), a poly-iodinated xanthene dye and an FDA-approved food colorant (FD&C Red No. 3), which we have identified recently as a promiscuous inhibitor of protein-protein interactions (PPIs) with a remarkably consistent median inhibitory concentration (IC50 ) in the 5- to 30-μM range. Because ErB exhibits metachromasy, that is, color change upon binding to several proteins, we exploited this property to quantify its binding to proteins such as bovine serum albumin (BSA) and CD40L (CD154) and to determine the corresponding binding constants (Kd ) and stoichiometry (nb ) using spectrophotometric methods. Binding was reversible, and the estimated affinities for both protein targets obtained here (Kd values of 14 and 20 μM for BSA and CD40L, respectively) were in good agreement with that expected from the PPI inhibitory activity of ErB. A stoichiometry greater than one was observed both for CD40L and BSA binding (nb of 5-6 and 8-9 for BSA and CD40L, respectively), indicating the possibility of nonspecific binding of the flat and rigid ErB molecule at multiple sites, which could explain the promiscuous PPI inhibitory activity if some of these overlap with the binding site of the protein partner and interfere with the binding.

Halogenation Generates Effective Modulators of Amyloid-Beta Aggregation and Neurotoxicity

Halogenation of organic compounds plays diverse roles in biochemistry, including selective chemical modification of proteins and improved oral absorption/blood-brain barrier permeability of drug candidates. Moreover, halogenation of aromatic molecules greatly affects aromatic interaction-mediated self-assembly processes, including amyloid fibril formation. Perturbation of the aromatic interaction caused by halogenation of peptide building blocks is known to affect the morphology and other physical properties of the fibrillar structure. Consequently, in this article, we investigated the ability of halogenated ligands to modulate the self-assembly of amyloidogenic peptide/protein. As a model system, we chose amyloid-beta peptide (Aβ), which is implicated in Alzheimer’s disease, and a novel modulator of Aβ aggregation, erythrosine B (ERB). Considering that four halogen atoms are attached to the xanthene benzoate group in ERB, we hypothesized that halogenation of the xanthene benzoate plays a critical role in modulating Aβ aggregation and cytotoxicity. Therefore, we evaluated the modulating capacities of four ERB analogs containing different types and numbers of halogen atoms as well as fluorescein as a negative control. We found that fluorescein is not an effective modulator of Aβ aggregation and cytotoxicity. However, halogenation of either the xanthenes or benzoate ring of fluorescein substantially enhanced the inhibitory capacity on Aβ aggregation. Such Aβ aggregation inhibition by ERB analogs except rose bengal correlated well to the inhibition of Aβ cytotoxicity. To our knowledge, this is the first report demonstrating that halogenation of aromatic rings substantially enhance inhibitory capacities of small molecules on Aβ-associated neurotoxicity via Aβ aggregation modulation.

Antimicrobial effect of photodynamic therapy using high‐power blue light‐emitting diode and red‐dye agent on Porphyromonas gingivalis

Antimicrobial photodynamic therapy (a-PDT) using a combination of red-colored laser/light-emitting diode (LED) and blue dye has been employed for periodontal therapy and the antimicrobial effect seems promising. Blue light, which has favorable wavelength properties, would be more effective as a light source for a-PDT because blue light itself possesses an antimicrobial effect. This study aimed to investigate the effect of a-PDT using a novel combination of high-power blue LED and red-dye agent on Porphyromonas gingivalis in vitro. Porphyromonas gingivalis ATCC 33277 suspension was irradiated with blue LED (BL) (425-470nm) or red LED (RL) (625-635nm) at 30-90J/cm(2) , or was mixed with erythrosine (ER), phloxine B (PB) or rose bengal (RB) with or without BL irradiation (30J/cm(2) ). RL (30J/cm(2) ) in combination with toluidine blue was employed as positive control. All the suspensions of P. gingivalis were serially diluted, plated and incubated anaerobically, and the numbers of colony-forming units (CFUs) were counted on day 7. BL irradiation at 60 and 90J/cm(2) demonstrated a significant reduction in the numbers of CFUs. ER, PB and RB solutions at 160μg/mL showed almost no or only a minimal reduction in the numbers of CFUs. BL at 30J/cm(2) combined with ER, PB or RB at 160μg/mL resulted in a log reduction of 0.9, 1.0 and 7.1, respectively, in the numbers of CFUs; 30J/cm(2) BL with RB at 1.6, 16 and 160μg/mL demonstrated a log reduction of 6.3, 8.0 and 5.5, respectively; and a log reduction of 5.2 was obtained after 30J/cm(2) RL with 16μg/mL TB. Within the limits of this study, BL was found to have an antimicrobial/growth-inhibiting effect on P. gingivalis, and a-PDT using a combination of BL and RB shows promise as a new technical modality for bacterial elimination in periodontal therapy.

Incorporation of Erythrosin B Within the Restricted Geometry of Langmuir Monolayer and Langmuir-Blodgett Films of Octadecylamine

This paper reports the monolayer characteristics of cationic octadecylamine (ODA) on both distilled water and aqueous Erythrosine B (EB) dye solution at the air-water interface. From the pressure-area isotherms at various pHs, EB anions in the subphase were found to interact with the insoluble monolayer of cationic octadecylamine (ODA). Adsorption kinetics shows that the amount of dye adsorbed depends on the concentration of the dye present in the subphase. It was observed that the adsorption process mainly occurred due to the electrostatic interaction between the cationic amino group of long chain amine and the anionic part of EB. The spectroscopic characteristics of the mixed LB films, solution, have been compared using UV-vis absorption and fluorescence spectroscopic data. These studies indicate the formation of aggregates in the thin films. Scanning electron microscopic study certainly confirms the presence of aggregates of EB dye in the (ODA-EB) mixed LB films.

Blue light (470 nm) effectively inhibits bacterial and fungal growth

Blue light (470nm) LED antimicrobial properties were studied alone against bacteria and with or without the food grade photosensitizer, erythrosine (ERY) against filamentous fungi. Leuconostoc mesenteroides (LM), Bacillus atrophaeus (BA) or Pseudomonas aeruginosa (PA) aliquots were exposed on nutrient agar plates to Array 1 (AR1, 0·2mWcm(-2)) or Array 2 (AR2, 80mWcm(-2)), which emitted impure or pure blue light (0-300Jcm(-2)), respectively. Inoculated control (room light only) plates were incubated (48h) and colonies enumerated. The antifungal properties of blue light combined with ERY (11·4 and 22·8μmoll(-1)) on Penicillium digitatum (PD) and Fusarium graminearum (FG) conidia were determined. Conidial controls consisted of: no light, room light-treated conidia and ERY plus room light. Light-treated (ERY+blue light) conidial samples were exposed only to AR2 (0-100Jcm(-2)), aliquots spread on potato dextrose agar plates, incubated (48h, 30°C) and colonies counted. Blue light alone significantly reduced bacterial and FG viability. Combined with ERY, it significantly reduced PD viability. Blue light is lethal to bacteria and filamentous fungi although effectiveness is dependent on light purity, energy levels and microbial genus. Light from two arrays of different blue LEDs significantly reduced bacterial (Leuconostoc mesenteroides, Bacillus atrophaeus and Pseudomonas aeruginosa) viabilities. Significant in vitro viability loss was observed for the filamentous fungi, Penicillium digitatum and Fusarium graminearum when exposed to pure blue light only plus a photosensitizer. F. graminearum viability was significantly reduced by blue light alone. Results suggest that (i) the amount of significant loss in bacterial viability observed for blue light that is pure or with traces of other wavelengths is genus dependent and (ii) depending on fungal genera, pure blue light is fungicidal with or without a photosensitizer.

Synthesis and characterization of fluorescent PEG-polyurethane with free carboxyl groups

A series of fluorescent multiblock PEG-polyurethane copolymers with free carboxyl groups were synthesized by one-step method and their chemical structure and properties were investigated. The multiblock PEG-polyurethane copolymers were composed of poly(ethylene glycol) (PEG), 1,6-hexamethylene diisocyanate, 2,2-bis(hydroxymethyl) propionic acid and a fluorescent dye erythrosine B (EB). The resulting polymers were examined by 1HNMR, FT-IR, gel permeation chromatography (GPC), ultraviolet visible spectroscopy (UV–vis), fluorescent spectroscopy. As a result, the UV–vis spectra showed that EB can be successfully conjugated into PEG-polyurethane during the one-step reaction. And the UV absorption peaks of samples were blue-shift and strengthened with decreasing of pH values, indicating that PEG-polyurethane-EB can be a pH-dependent fluorescent probe in a broad pH range. We expect that more applications would be possible for the fluorescent PEG-polyurethane with free carboxyl groups owing to its free functional groups and simultaneously imaging along with pH values.

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 (10(6) 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; log10) 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 log10 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.

Chitosan Nanoparticles for Antimicrobial Photodynamic Inactivation: Characterization and In Vitro Investigation†

The growing resistance to antibiotics has rendered antimicrobial photodynamic inactivation (PDI) an attractive alternative treatment modality for infectious diseases. Chitosan (CS) was shown to further potentiate the PDI effect of photosensitizers and was therefore used in this study to investigate its ability to potentiate the activity of erythrosine (ER) against bacteria and yeast. CS nanoparticles loaded with ER were prepared by ionic gelation method and tested for their PDI efficacy on planktonic cells and biofilms of Streptococcus mutans, Pseudomonas aeruginosa and Candida albicans. The nanoparticles were characterized for their size, polydispersity index and zeta potential. No toxicity was observed when planktonic cells and biofilms were treated with the nanoparticles in the dark. However, when the cells were exposed to light irradiation after treatment with free ER or ER/CS nanoparticles, a significant phototoxicity was observed. The antimicrobial activity of ER/CS nanoparticles was significantly higher than ER in free form. The particle size and incubation time of the nanoparticles also appeared to be important factors affecting their PDI activity against S. mutans and C. albicans.

Investigation on the Competition Interaction of Synthetic Food Colorants and Ciprofloxacin Hydrochloride with Bovine Serum Albumin by Fluorescence Spectroscopy

The effects of synthetic food colorants like tartrazine (TTZ), sunset yellow (SY), and erythrosine (ETS) on the binding reaction between ciprofloxacin hydrochloride (CPFX) and bovine serum albumin (BSA) were investigated by fluorescence spectroscopy in the aqueous solution of pH = 7.40. Results showed that CPFX caused the fluorescence quenching of BSA through a static quenching procedure and the primary binding site was located at subdomain IIA of BSA (site I). According to the calculated thermodynamic parameters, it confirmed that CPFX bound to BSA by electrostatic interaction. In addition, the colorants affected the formation of BSA-CPFX complex. This resulted in an increase of the free, biological active fraction of CPFX. The binding distance of BSA-CPFX systems was evaluated according to Förster's theory. Results suggested that the binding distance were increased in the presence of synthetic food colorants.

The antimicrobial activity of photodynamic therapy against Streptococcus mutans using different photosensitizers

Several photosensitizers have been used against oral bacteria without standardization. Singlet oxygen ( 1O 2) is an aggressive chemical species that can kill cells through apoptosis or necrosis. Objective: to compare the antimicrobial activity of photodynamic therapy (PDT) with different photosensitizers at the same concentration against Streptococcus mutans. In addition, the 1O 2 production of each photosensitizer was determined. The photosensitizers (163.5 μM) methylene blue (MB), toluidine blue ortho (TBO) and malachite green (MG) were activated with a light-emitting diode (LED; λ = 636 nm), while eosin (EOS), erythrosine (ERI) and rose bengal (RB) were irradiated with a curing light ( λ = 570 nm). Light sources were operated at 24 J cm −2. For each photosensitizer, 40 randomized assays ( n = 10 per condition) were performed under one of the following experimental conditions: no light irradiation or photosensitizer, irradiation only, photosensitizer only or irradiation in the presence of a photosensitizer. After treatment, serial dilutions of S. mutans were seeded onto brain heart infusion agar to determine viability in colony-forming units per milliliter (CFU mL −1). Generation of 1O 2 was analyzed by tryptophan photooxidation, and the decay constant was estimated. Results were analyzed by one-way ANOVA and the Tukey–Kramer test ( p < 0.05). PDT with irradiation in the presence of the photosensitizers TBO and MG was effective in reducing S. mutans counts by 3 and 1.4 logs, respectively ( p < 0.01), compared to their respective untreated controls. MB generated 1.3 times more 1O 2 than TBO, and both produced significantly higher concentrations of singlet oxygen than the other photosensitizers. Since in vitro bulk 1O 2 production does not indicate that 1O 2 was generated in the bacterial activity site, the bactericidal action against S. mutans cannot be related to in vitro singlet O 2 generation rate. In vitro S. mutans-experiments demonstrated TBO as the only photosensitizer that effectively reduced 99.9% of these microorganisms.

Susceptibility of Candida albicans and Candida dubliniensis planktonic cultures and biofilms to erythrosine- and LED-mediated photodynamic therapy

Susceptibility of Candida albicans and Candida dubliniensis planktonic cultures and biofilms to erythrosine- and LED-mediated photodynamic therapy