Photodynamic antimicrobial therapy (A-PDT) using 1,9-Dimethyl-Methylene Blue zinc chloride double salt - DMMB and λ640 ± 5ηm LED light in patients undertaking orthodontic treatment.

Orthodontic treatment involves the use of apparatuses that impairs oral hygiene making patients susceptible to periodontal diseases and caries. To prevent increased antimicrobial resistance A-PDT has shown itself a feasible option. The aim of this investigation was to assess the efficiency of A-PDT employing 1,9-Dimethyl-Methylene Blue zinc chloride double salt - DMMB as a photosensitizing agent combined with red LED irradiation (λ640 ± 5 ηm) against oral biofilm of patients undertaking orthodontic treatment. Twenty-one patients agreed to participate. Four biofilm collections were carried out on brackets and gingiva around inferior central incisors; first was carried out before any treatment (Control); second followed five minutes of pre-irradiation, the third was immediately after the first AmPDT, and the last after a second AmPDT. Then, a microbiological routine for microorganism growth was carried out and, after 24-h, CFU counting was performed. There was significant difference between all groups. No significant difference was seen between Control and Photosensitizer and AmpDT1 and AmPDT2 groups. Significant differences were observed between Control and AmPDT1 and AmPDT2 groups, Photosensitizer and AmPDT1 and AmPDT2 groups. It was concluded that double AmPDT using DMBB in nano concentration and red LED was capable to meaningfully decrease the number of CFUs in orthodontic patients.

Evaluation of dual application of photodynamic therapy-PDT in Candida albicans.

This study aimed to evaluate, in vitro, the efficacy of photodynamic therapy - PDT using dimethyl methylene blue zinc chloride double salt (DMMB) and red LED light on planktonic cultures of Candida albicans. The tests were performed using the ATCC 90,028 strain grown at 37 °C for 24 h, according to a growth curve of C. albicans. The colonies were resuspended in sterile saline adjusted to a concentration of 2 × 108 cells / mL, with three experimental protocols being tested (Protocol 1, 2 and 3) with a fixed concentration of 750 ɳg/mL obtained through the IC50, and energy density 20 J/cm2. Protocol 1 was carried out using conventional PDT, Protocol 2 was applied double PDT in a single session, and Protocol 3 was applied double PDT in two sessions with a 24 h interval. The results showed logarithmic reductions of 3 (4.252575 ± 0.068526) and 4 logs (2.669533 ± 0.058592) of total fungal load in protocols 3 and 2 respectively in comparison to the Control (6.633547 ± 0.065384). Our results indicated that double application in a single session of PDT was the most effective approach for inhibiting the proliferation of Candida albicans (99.991% inhibition).

Histological evaluation of skin lesions induced by Leishmania braziliensis treated by PACT using Laser light and 1.9 dimethyl-methylene blue.

This study aimed to perform a histological evaluation in skin lesions caused by Leishmania braziliensis after PACT treatment using Laser associated with 1.9. dimethyl methylene blue BALB/c mouse ear infection model was used. A total of 40 animals were assigned into two groups considering time intervals at 5 and 10 weeks and subdivided into four subgroups: Control, Photosensitizer, Laser and PACT. Two therapeutic interventions were performed after the 5th week of infection at 48 h intervals. 1.9 Dimethyl methylene blue was used as a photosensitizer at the concentration of 7 ng/mL, with a non-invasive topical administration method associated with Laser (λ = 660 nm, 40 mW, 12 J/cm2). Sample collection occurred 5 or 10 weeks after therapeutic interventions. The main histological findings were observed in the laser and PACT groups at the 10-week evaluation. The Laser group showed reduced lymphoplasmacytic inflammation and histiocytes (p = 0.0079). The PACT group showed reductions in lymphoplasmacytic inflammation at 5 and 10 weeks, discrete reduction of histiocytes and a higher percentage of tissue remodeling. PACT with non-invasive topical administration of the photosensitizer was able to reduce lymphoplasmacytic inflammation and increase tissue remodeling in leishmaniosis skin lesions. This protocol may be easily used in humans and clinical trial shall be carried out to confirm the animal's findings.

Production and viscosity of Xanthan Gum are increased by LED irradiation of X. campestris cultivated in medium containing produced water of the oil industry.

Oil recovery is a challenge and microbial enhanced oil recovery is an option. We theorized that the use of produced water (PW) with photo-stimulation could influence both production and viscosity of Xanthan gum. This study aimed at the evaluation of the effect of photo-stimulation by λ630 ± 1 ηm LED light on the biosynthesis of Xanthan gum produced by Xanthomonas campestris IBSBF 2103 strain reusing PW of the oil industry. We assessed the effect of photo-stimulation by LED light (λ630 nm) on the biosynthesis of Xanthan gum produced by X. campestris in medium containing produced water. Different energy densities applied during the microbial growth phase were tested. The highest production was achieved when using 12 J/cm2 LED light (p < 0.01). Three protocols were assessed: Non-irradiated (Control), Irradiation with LED light during the growth phase (LEDgrowth) and Irradiation with LED light during both growth and production phases (LED growth+production). Both the amount and viscosity of the xanthan gum was significantly higher (p < 0.01) in the group LEDgrowth+production. The study showed that LED irradiation (λ630 ± 1 ηm) during both the growth and production phases of the biopolymer increased both the production and viscosity of Xanthan gum.

The use of photobiomodulation therapy or LED and mineral trioxide aggregate improves the repair of complete tibial fractures treated with wire osteosynthesis in rodents.

The repair of large bone defects is lengthy and complex. Both biomaterials and phototherapy have been used to improve bone repair. We aimed to describe histologically the repair of tibial fractures treated by wiring (W), irradiated or not, with laser (λ780 nm, 70 mW, CW, spot area of 0.5 cm2, 20.4 J/cm2 (4 × 5.1 J/cm2, Twin Flex Evolution®, MM Optics, Sao Carlos, SP, Brazil) per session, 300 s, 142.8 J/cm2 per treatment) or LED (λ850 ± 10 nm, 150 mW, spot area of 0.5 cm2, 20.4 J/cm2 per session, 64 s, 142.8 J/cm2 per treatment, Fisioled®, MM Optics, Sao Carlos, Sao Paulo, Brazil) and associated or not to the use of mineral trioxide aggregate (MTA, Angelus®, Londrina, PR, Brazil). Inflammation was discrete on groups W and W + LEDPT and absent on the others. Phototherapy protocols started immediately before suturing and repeated at every other day for 15 days. Collagen deposition intense on groups W + LEDPT, W + BIO-MTA + LaserPT and W + BIO-MTA + LEDPT and discrete or moderate on the other groups. Reabsorption was discrete on groups W and W + LEDPT and absent on the other groups. Neoformation varied greatly between groups. Most groups were partial and moderately filed with new-formed bone (W, W + LaserPT, W + LEDPT, W + BIO-MTA + LEDPT). On groups W + BIO-MTA and W + BIO-MTA + LaserPT bone, neoformation was intense and complete. Our results are indicative that the association of MTA and PBMT (λ = 780 nm) improves the repair of complete tibial fracture treated with wire osteosynthesis in a rodent model more efficiently than LED (λ = 850 ± 10 nm).

Effects of photo-stimulation with laser or LED on the composition of Xanthan gum produced in media containing distilled water or dialyzed or not produced water by means of Raman spectroscopy.

Oil is expected to continue to be one of the most important sources of energy in the world and world's energy matrix for the foreseeable future. However, high demand for energy and the decline of the production of oil fields makes oil recovery a challenge. Most techniques used for the recovery process are expensive, non-sustainable and technically difficult to implement. In this context, microbial enhanced oil recovery (MEOR) represents an attractive alternative. It employs products derived from the metabolism of microorganisms that produce biopolymers. Certain bacteria species (e.g., Xanthomonas campestris) produce polysaccharides (exopolysaccharides - EPS) such as the well-known Xanthan gum (XG). We hypothesized that the use of produced water (PW) water in combination photo-stimulation with laser/LED could influence the production and composition of XG. Raman spectroscopy has been used for qualitative and quantitative evaluation of the biochemical composition of XG biopolymer under light stimulation. X. campestris cultures in either distilled water or dialysis-produced water were studied under the absence or presence of laser irradiation (λ = 660 nm, CW, spot size 0.040 cm2, 40 mW, 444 s, 8.0 J/cm2) or LED (λ = 630 nm ± 2 nm, CW, spot size 0.50 cm2, 140 mW, 500 s, 12 J/cm2). XG produced by these cultures was analyzed by Raman spectroscopy at 1064 nm excitation and subjected to principal component analysis (PCA). Results of the exploratory analysis and ANOVA general linear model (GLM) suggested that the extent of XG and pyruvate (pyruvyl mannose) production was affected differentially in X. campestris when cultured in distilled water plus LED photo-stimulation versus dialysis-produced water plus LED photo-stimulation. XG production increased in the distilled water culture. In contrast, both pyruvate acetyl mannose content went up in the dialysis-water culture. These results open a wide field of opportunities in the use of metal-enriched cultures in combination with photo-biomodulation to direct and optimize bacterial production of compounds (i.e., XG) that may be of great benefit in the implementation of sustainable practices for oil extraction.

Composition of Xanthan gum produced by Xanthomonas campestris using produced water from a carbonated oil field through Raman spectroscopy.

Produced water (PW) is a by-product generated throughout oil exploration. Geological formation and geographical location of the reservoir influence its physical, chemical and biological characteristics. Xanthan gum (XG), an exopolysaccharide (EPS) produced by Xanthomonas campestris, has been widely used in enhanced oil recovery (EOR) technology because of its high viscosity, pseudoplastic behavior, stability in function of salinity, temperature and alkaline conditions. The production of XG may be affected by the composition of the PW, where the acetyl and pyruvyl radicals may be present in the mannoses. The aim of this study was to evaluate the composition of XG produced by X. campestris, particularly the amount of Xanthan, acetyl and pyruvyl groups, in culture mediums containing distilled (DW) or produced (PW) water in different concentrations, by means of dispersive Raman spectroscopy (1064 nm). The spectra of XG showed peaks referred to the main constituents of the Xanthan (glucose, mannose and glucuronic acid). Spectral features assigned to pyruvyl were seen in all samples mainly at ~1010 cm-1, with higher intensity when using DW and 25% PW. PCA loadings showed that the peaks assigned to pyruvyl are consistent to presence of sodium pyruvate (~1040/~1050 and ~ 1432 cm-1) and were higher in the samples obtained in 25% PW. ANOVA GLM applied to Raman peaks of interest (~1010 and ~ 1090 cm-1) and to PCA scores (Score 1 to Score 3) showed that both were influenced by the type of water used in the culture medium, where the XG were strongly reduced in the groups PW compared to DW while the pyruvyl content increased proportionally with the concentration of PW. The results suggest that the composition of the water used in the bacteria's culture medium influenced the composition of XG, including the amount of Xanthan and particularly the pyruvyl content, and therefore needs to be considered when using this approach of injecting XG in oil fields as pyruvyl content affects viscosity.

Enhancement of photodynamic inactivation of planktonic cultures of Staphylococcus aureus by DMMB-AuNPs.

Photodynamic inactivation is a promising method for the treatment of infectious diseases. Nanotechnology through gold nanoparticles, as a tool to improve the delivery of photosensitizer is an attractive approach to enhance photodynamic inactivation of bacteria. Moreover, gold nanoparticles enchance the absorption of light due to their plasmon resonance. The aim of this study was to evaluate in vitro photodynamic inactivation effects of 1.9-Dimethyl-Methylene Blue (DMMB)-AuNPs associated with the red LED (λ630 ηm ± 20 ηm, 125 mW, 12 J / cm², 192 s) on S. aureus strain. Eight experimental groups were studied: Control, LED, AuNPs, AuNPs + LED, DMMB, DMMB + LED, DMMB + AuNPs, DMMB + AuNPs + LED. After incubation, the number of bacteria surviving each treatment was determined and then enumerated by viable counting (CFU / mL). The logarithm of CFU / mL (CFU/mL log10) was calculated. All experiments realized in triplicate. The statistical analyses included one-way ANOVA tests, Tukey's multiple comparisons and nonlinear regression, p values <0.05 were considered statistically significant. According to results, the photodynamic inactivation of S. aureus on groups DMMB + LED and DMMB-AuNPs + LED, showed a significant reduction of the microbial load (p < 0.0001) when compared to the Control group. The decimal reduction (RD) of these groups were 99.96 % (RD = 3) and 99.994 % (RD = 4) respectively. In conclusion, these findings demonstrated that photodynamic inactivation is enhanced by using DMMB-AuNPs on S. aureus.

Raman spectroscopic study of the effect of the use of laser/LED phototherapy on the repair of complete tibial fracture treated with internal rigid fixation.

This study aimed to assess the repair of complete surgical tibial fractures fixed with internal rigid fixation (IRF) associated or not to the use of mineral trioxide aggregate (MTA) cement and treated or not with laser (λ = 780 nm, infrared) or LED (λ = 850 ±â€¯10 nm, infrared) lights, 142.8 J/cm2 per treatment, by means of Raman spectroscopy. Open surgical tibial fractures were created on 18 rabbits (6 groups of 3 animals per group, ∼8 months old) and fractures were fixed with IRF. Three groups were grafted with MTA. The groups of IRF and IRF + MTA that received laser or LED were irradiated every other day during 15 days. Animals were sacrificed after 30 days, being the tibia surgically removed. Raman spectra were collected via the probe at the defect site in five points, resulting in 15 spectra per group (90 spectra in the dataset). Spectra were collected at the same day to avoid changes in laser power and experimental setup. The ANOVA general linear model showed that the laser irradiation of tibial bone fractures fixed with IRF and grafted with MTA had significant influence in the content of phosphate (peak ∼960 cm-1) and carbonated (peak ∼1,070 cm-1) hydroxyapatites as well as collagen (peak 1,452 cm-1). Also, peaks of calcium carbonate (1,088 cm-1) were found in the groups grafted with MTA. Based on the Raman spectroscopic data collected in this study, MTA has been shown to improve the repair of complete tibial fractures treated with IRF, with an evident increase of collagen matrix synthesis, and development of a scaffold of hydroxyapatite-like calcium carbonate with subsequent deposition of phosphate hydroxyapatite.

Detection of prostate cancer by Raman spectroscopy: A multivariate study on patients with normal and altered PSA values.

Digital rectal examination (DRE) was the primary means to detect prostate diseases. The DRE has a high variability as it is based manly in the tactile sensitivity and expertise of the examiner. The prostate-specific antigen (PSA) test was initially developed for surveillance of prostate cancer and later it was also used as a diagnosis test. Raman spectroscopy is a powerful analytical technique that can measure the chemical composition of complex biological samples, such as body fluids. Biochemical changes caused by diseases can lead to significant changes in the Raman spectra. This study aimed to identify the differences in the Raman spectra of serum samples with normal and altered PSA values and correlate these differences by using multivariate techniques (principal component analysis - PCA and partial least squares regression - PLS). A total of 321 spectra were collected from 108 subjects. Two hundred and seventy were obtained from 91 non-altered PSA samples and 51 spectra from 17 samples with altered PSA. Each spectrum acquired was standardized to the area under the curve (1-norm). Discriminating and quantitative models employing PCA and PLS were developed. The PCA analyses showed 85.7% predictive power (87.41% sensitivity and 76.47% specificity). The PLS test showed a near-perfect sensitivity (98.51%) and an intermediate specificity (62.75%). The quantitative model through PLS regression showed a good correlation between PSA values and the spectral features (r = 0.605). This preliminary study suggests that Raman spectroscopy could be efficiently used for screening patients with altered PSA as well as for follow-up of the treatment of the prostate cancer by using initially the PLS to identify the possible presence of the prostate cancer and later on use de PCA to confirm the diagnosis.

aPDT using nanoconcentration of 1,9-dimethylmethylene blue associated to red light is efficacious in killing Enterococcus faecalis ATCC 29212 in vitro.

The Enterococcus faecalis is a microorganism that causes multiple forms of resistance to a wide range of drugs used clinically. aPDT is a technique in which a visible light activates photosensitizer (PS), resulting in generation of reactive oxygen species that kill bacteria unselectively via an oxidative burst. aPDT is an alternative to antibiotics with the advantage of not causing resistance. The search for an alternative treatment of infections caused by E. faecalis, without using antibiotics, is off great clinical importance. The aim of present investigation was to assess the efficacy of using 3.32 ηg/mL of 1,9-dimethylmethylene blue (DMMB) as photosensitizer associated with the use of either Laser (λ660 nm) or LED (λ632 ±â€¯2 nm) using different energy densities (6, 12 and 18 J/cm2) to kill E. faecalis in vitro. Under different experimental conditions, 14 study groups, in triplicate, were used to compare the efficacy of the aPDT carried out with either the laser or LED lights using different energy densities associated to DMMB. The most probable number method (MPN) was used for quantitative analysis. Photodynamic antimicrobial effectiveness was directly proportional to the energy density used, reaching at 18 J/cm2, 99.999998% reduction of the counts of E. faecalis using both light sources. The results of this study showed that the use of 3.32 ηg/mL of DMMB associated with the use 18 J/cm2 of LED light (λ632 ±â€¯2 nm) reduced >7-log counts of planktonic culture of E. faecalis.

Photobiomodulation Therapy in Oral Medicine: A Guide for the Practitioner with Focus on New Possible Protocols.

Photobiomodulation (PBM) is the term to define the wide range of laser applications using low-energy densities and based on photochemical mechanisms where the energy is transferred to the intracellular mitochondrial chromophores and respiratory chain components. In literature, a great number of works are reported showing the advantages of PBM use in many oral diseases such as recurrent aphthous stomatitis, herpes infections, mucositis, and burning mouth syndrome. Different factors may explain the increasing reported use of PBM in oral medicine: the absence of side effects, the possibility of safely treating compromised patients such as oncologic patients, the possibility of a noninvasive approach not associated with pain or discomfort, and the possibility of performing short sessions. The review's aim is to describe the possible applications of PBM in oral medicine, giving practitioners simple guide for practice together with the information of a new treatment possibility "at home" performed by the patient himself under supervision.

Oral microbiological control by photodynamic action in orthodontic patients.

BACKGROUND: Orthodontics involves diagnosis and treatment of dental and skeletal malocclusions. Orthodontic apparatus may repair these malocclusions but may also impair oral hygiene making patients prone to develop both periodontal diseases and caries. Antimicrobial agents may be used to prevent this.To avoid increased antimicrobial resistance to available drugs, A-PDT (Antimicrobial Photodynamic Therapy) appears as a viable alternative. OBJECTIVE: This work aimed to evaluate the efficacy of A-PDT on reducing the number of colony forming units (CFU) through the use of phenothiazine compound (methylene blue+ toluidine blue) as a photosensitizer, associated with red LED (λ640±5ηm) irradiation in orthodontic patients. METHODOLOGY: Twenty-one patients consented to participate in the study. Three biofilm collections were performed around the brackets and gums of the inferior central incisors; first before any intervention (Control); second after 5min of pre-irradiation and the last one immediately after AmPDT. Subsequently, a microbiological routine for microorganism growth period were performed and CFU counting after a 24h done. RESULTS: The data showed that the AmPDT was able to reduce CFU count around 90% when compared to Control group (p=0.007) and also between the A-PDT and Photosensitizer groups (p=0.010). However, there were no differences between the Control and Photosensitizer groups. CONCLUSION: A-PDT associated with the use of phenothiazine compounds and red LED was able to significantly reduce the number of CFUs in orthodontic patients.

Effects of photostimulation on the catabolic process of xenobiotics.

Light biotechnology is a promising tool for enhancing recalcitrant compounds biodegradation. Xenobiotics can cause a significant impact on the quality of the results achieved by sewage treatment systems due to their recalcitrance and toxicity. The optimization of bioremediation and industrial processes, aiming to increase efficiency and income is of great value. The aim of this study was to accelerate and optimize the hydrolysis of Remazol Brilliant Blue R by photo stimulating a thermophilic bacterial consortium. Three experimental groups were studied: control group; LED Group and Laser Group. The control group was exposed to the same conditions as the irradiated groups, except exposure to light. The samples were irradiated in Petri dishes with either a Laser device (λ660 nm, CW, θ = 0.04 cm2, 40 mW, 325 s, 13 J/cm2) or by a LED prototype (λ632 ±â€¯2 nm, CW, θ = 0.5 cm2, 145 mW, 44 s, 13 J/cm2). We found that, within 48-h, statistically significant differences were observed between the irradiated and the control groups in the production of RNA, proteins, as well as in the degradation of the RBBR. It is concluded that, both Laser and LED light irradiation caused increased cellular proliferation, protein production and metabolic activity, anticipating and increasing the catabolism of the RBBR. Being the economic viability a predominant aspect for industrial propose our results indicates that photo stimulation is a low-cost booster of bioprocesses.

ROS-induced autophagy reduces B16F10 melanoma cell proliferative activity.

Cancer is a pathology characterized by increased cell progression and/or reduced programmed cell death. Melanoma shows a rapid increase in cell progression and its resistance to chemotherapy is associated with uncontrolled apoptosis and to mechanisms that increase the flow of the drug out of the cell. The objective of this study was to evaluate the effects of photodynamic therapy (PDT) on the cell proliferation and cellular alterations in B16F10 murine melanoma. For that, four experimental groups were evaluated: the control group; laser group (ʎ = 660 Î·m, 40 mW, 2.4 J/cm2); photosensitizer group (solution containing methylene blue and toluidine blue 1:1-12.5 µg/mL); PDT group. The incubation time was 30 min. Fluorescence microscopy assays were performed without fixation with the DAPI, monodansylcadaverine (MDC), and dihydroethidium (DHE) probes. Cell proliferation was also determined at 24-h time. The tests were performed in triplicate and the statistical test used was ANOVA with Tukey post-test. The results demonstrate that the plasma membrane of the cells of all the experimental groups remained intact, ROS production and autophagy significantly increased (p < 0.0005 and p < 0.0071, respectively) only in the PDT group. The cell proliferation essay showed a reduction of 74.2% on the PDT group in relation to the control group. The present study demonstrated that oxidative stress promoted by photodynamic therapy may induce autophagy and consequently reduce cell proliferation in B16F10 melanoma.

Laser/LED phototherapy on the repair of tibial fracture treated with wire osteosynthesis evaluated by Raman spectroscopy.

The aim of the present study was to assess, by means of Raman spectroscopy, the repair of complete surgical tibial fractures fixed with wire osteosynthesis (WO) treated or not with infrared laser (λ780 nm) or infrared light emitting diode (LED) (λ850 ± 10 nm) lights, 142.8 J/cm2 per treatment, associated or not to the use of mineral trioxide aggregate (MTA) cement. Surgical tibial fractures were created on 18 rabbits, and all fractures were fixed with WO and some groups were grafted with MTA. Irradiated groups received lights at every other day during 15 days, and all animals were sacrificed after 30 days, being the tibia removed. The results showed that only irradiation with either laser or LED influenced the peaks of phosphate hydroxyapatite (~ 960 cm-1). Collagen (~ 1450 cm-1) and carbonated hydroxyapatite (~ 1070 cm-1) peaks were influenced by both the use of MTA and the irradiation with either laser or LED. It is concluded that the use of either laser or LED phototherapy associated to MTA cement was efficacious on improving the repair of complete tibial fractures treated with wire osteosynthesis by increasing the synthesis of collagen matrix and creating a scaffold of calcium carbonate (carbonated hydroxyapatite-like) and the subsequent deposition of phosphate hydroxyapatite.

Effects of PACT using phenothiazine-derived drugs and red light on the macrophage x S. aureus interface.

The aim of this study was to evaluate the lethal potential of macrophages infected with Staphylococcus aureus after PACT (Photochemical Antimicrobial Chemotherapy) using phenothiazine derivatives (a solution containing 1:1 methylene blue and O toluidine blue) and laser (660 nm, 40 mW, 60 s, 12 J/cm2) or LED (632 ±â€¯2 nm, 145 mW, 40 s, 12 J/cm2). Six experimental groups were evaluated: Control Group (untreated); Photosensitizer group (phenothiazines - 12.5 µg/mL); Laser Group; LED Group; Laser PACT Group; and LED PACT Group. The pre-irradiation time used in this study was 5 min. Macrophages and bacteria were cultured in specific culture media and/or allowed interaction between the cell types. Subsequently, tests were carried out to evaluate microbial proliferation, ROS production by macrophages and survival capacity of S. aureus after phagocytosis. Fluorescence microscopy assays were performed with the H2DCFDA probe, after PACT, at the initial time (0 h), 4-h and 12-h. The tests were performed in triplicate and the statistical test used was ANOVA with Tukey post-test. After PACT, a statistically significant difference (p > 0.0001) was observed between the microbial growth of the control group and the PACTs groups. Laser PACT and LED PACT groups presented, respectively, reductions of 84.2% and 81.5% when compared to control and 53.3% and 46% when compared to the photosensitizer group. It is concluded that the therapeutic protocols presented in this study increased the phagocytic capacity, the response rate of the phagocytes and the consequent reduction of the numbers of S. aureus for both PACT protocols, however the increase in ROS production was only observed in the group irradiated with Laser light.

Photobiological effect of Laser or LED light in a thermophilic microbial consortium.

Cellulose has a highly diversified architecture and its enzymatic complexes are studied for achieving an efficient conversion and a high level of efficiency in the deconstruction of cellulolytic biomass into sugars. The aim of this investigation was to evaluate the effect of Laser or LED light in the cellulolytic activity (CMCase) and on the proliferation of the thermophilic microbial consortium used on the degradation process of a lignocellulosic biomass of green coconut shell. The irradiation protocol consisted of six Laser irradiations (λ660 ηm, 40 mW, 270 s, 13 J/cm2) or LED (λ632 ±â€¯2 ηm, 145 mW, 44 s, 13 J/cm2) with 12- h time intervals in nutrient deprivation conditions. After irradiation, the consortium was inoculated into a lignocellulosic biomass (coconut fibers). Non- irradiated consortium was also inoculated and acted as control. Cell proliferation and endoglucanase activity were quantified during the experimental time. Experiments were carried out in triplicate. The results showed an increase of 250 % of thermo-cellulolytic microorganisms for the LED group and 200% for the Laser group when compared to the control. The enzymatic index (red Congo method), showed a statistically significant difference in the process of degradation of the lignocellulosic biomass between the Laser and LED groups compared to the control group [p < 0.0029; p < 0.029, respectively] 48-hs after the inoculation of the microorganisms. At the end of 72-h, this significant difference was maintained for both irradiated groups (p < 0.0212). Based upon the protocol used on the present study, it is possible to concluded that LED light enhanced cell proliferation of the thermophilic microbial consortium while the Laser light increase the enzymatic index of the lignocellulosic biomass of green coconut shell.

LED antimicrobial photodynamic therapy with phenothiazinium dye against Staphylococcus aureus: An in vitro study.

The objective of this study was to evaluate, in vitro, the bactericidal effect of AmPDT on Staphylococcus aureus (ATCC 25923) using different concentrations (100, 50, 25, 12.5 and 6.25µg/mL) of phenothiazine compound combined with LED light (λ632±2nm) using varied energy densities (12, 9.6, 7.2, 4.8 and 2.4J/cm2). The experiments were carried out in triplicate and the samples were divided into groups: Control, Irradiated (treated only with light at different energy densities), Photosensitizer (treated only in the presence of the dye), AmPDT (treatment with light associated with dye). Counts of the colony forming units and the data obtained were statistically analyzed (ANOVA, Tukey's test, p<0.05). The results showed no difference between irradiated and Control groups. However, using the photosensitizer alone caused significant increased cytotoxicity and consequent reduction on the CFU counts (12.5µg/mL (p<0.001), 25µg/mL, 50µg/mL and 100µg/mL (p<0.0001). When AmPDT was used significant inhibition above 70% were detected for all concentrations of the photosensitize (p<0.0001) except for 6.25µg/mL. The results indicate a dose-response dependent when the photosensitizer is used alone but not for the sole use of the light is used. It is concluded that, a single application of AmPDT, using energy density of 12J/cm2 associated either to 12.5 (81.52%) or 25µg/mL (91.57%) resulted in higher in vitro inhibition of S. aureus.