Background: Photodynamic therapy (PDT) is alternative treatment of cutaneous leishmaniasis (CL), and phenolthiazine dyes such as Toluidine Blue O (TBO) have the potential role in PDT and notably affect parasites inactivation. This study aimed to evaluate the effectiveness of PDT by using TBO and a light-emitting diode (LED) in the treatment of zoonotic CL (ZCL). Methods: The study was conducted in Iran University of Medical Sciences, Tehran, Iran in 2018-2020. Different concentration (7. 8 µ, g/ mL up to 500 µ, g/ mL) of TBO as a photosensitizer and a 630 nm LED light as a source of light were used for antileishmanial activity against both forms of Leishmania major promastigotes and intracellular amastigotes. Effective concentration (EC50) and cell cytotoxicity (CC50) were calculated in both infected and non-infected J774. A1 macrophages, respectively. As well as inhibitory concentration (IC50) was quantified in L. major promastigotes for 2 h, 24 h, and 48 h after incubation using a MTT colorimetric assay. Results: TBO dye in combination with the PDT significantly decreases the L. major promastigotes and intracellular amastigotes viability when compared with TBO alone. Both TBO dye in combination with the PDT and TBO alone had no toxic effects on the mice macrophages,however, it significantly killed the entered parasites inside the cells. Our results in the current study established satisfactory findings in clearing intracellular L. major parasites in in-vitro conditions. Conclusion: TBO dye in combination with the PDT can be considered as a harmless, effective and importantly perfect treatment against L. major, causative agent of ZCL, in an in-vitro situation without any negative toxicity to the mice macrophages.

Introduction: Porphyromonas gingivalis is one of the major pathogens in the development and progression of periodontal disease. Antimicrobial photodynamic therapy (aPDT) is a new approach which is sorted in non-invasive phototherapy for bacterial elimination. This in vitro study was conducted to compare photodynamic inactivation using Radachlorin and Toluidine blue O (TBO) as photosensitizers on P. gingivalis.Methods: Bacterial suspensions (200 mL) of P. gingivalis were exposed to either TBO with concentration of 0.1 mg/mL associated with portable light-emitting diode (LED) device (peak wavelength: 630 nm, output intensity: 2.000 mW/cm2, tip diameter: 6.2 mm) or 0.1% RadachlorinÒ and laser irradiation (InGaAlP, Peak wavelength: 662±0.1% nm, output power: 2.5 W, energy density: 6 J/cm2, fiber diameter: 2 mm). Those in control groups were subjected to laser irradiation or LED alone, RadachlorinÒ or TBO alone, and one group received neither photosensitizer nor light irradiation. Then counting of colony forming units (CFU) was performed to determine the bactericidal effects in each subgroup.Results: LED-based aPDT reduced the colony count of P. gingivalis more than that of TBO (P<0.001) or LED group (P=0.957). Also, laser-based aPDT had a great reduction in colony count of P. gingivalis in comparison with RadachlorinÒ (P<0.001) or laser irradiation alone (P=0.28). In addition, the colony count reduction of laser-based aPDT was significantly more than LED-based aPDT (P<0.05).Conclusion: Considering the results of this study, the viability of P. gingivalis was more affected by the combination of laser and Radachlorin® 0.1% in comparison with LED and TBO 0.1%

Background & objective: Photodynamic inactivation (PDI) has been investigated to cope with the increasing incidence of multidrug-resistant (MDR) pathogens. PDI employs nontoxic photosensitizers (PSs), which localize in the microbial cells and are activated by a specific wavelength of visible light. The main purpose of this study was to explore the PDI effect of methylene blue (MB) and toluidine blue O (TBO) on Escherichia coli (ATCC 25922) and clinical isolate of multidrug-resistant Escherichia coli.Methods: Effect of PSs concentration (12.5, 25, 50 µg/ml) and laser irradiation time (10, 20, 30 min) on lethal photosensitization was investigated.Results: Methylene blue (50 µg/ml) photosensitization using red laser light (163.8 J/cm2) was able to achieve reductions of 53.1% and 37.6% in the viable counts of Escherichia coli (ATCC 25922) and clinical isolate of MDR Escherichia coli (using starting concentrations of 104–105 CFU ml-1). TBO at 50 µg/ml, 46.8 Jcm-2, exhibited 0.7 log killing for MDR E. coli and 1.7 log killing for E. coli (ATCC 25922).Conclusion: In our study, the selected MDR isolate was more resistant to TBO-PDI-mediated killing than its ATCC reference strain. Therefore, the PDI efficacy of TBO may be affected by the antibiotic resistance mechanism that presented in MDR isolate.

Introduction: Chemical antibacterial agents are increasingly being used in prophylactic therapeutic regimes for oral and plaque-related diseases. As the microorganism can be resistant to drugs so, there is a need for alternative antibacterial approaches.Bacteria can be sensitized to killing by light from low-power laser with chemical photosensitizing agents such as TBO. The aim of this study was to investigate the bacterial effect of Ga-As laser irradiation on oral microorganism.Methods: The microorganisms evaluated in this in vitro study were: S.mutans, Group A Beta Hemolytic streptococci, Neisseria, Bacteroides melaninogenicus.Diphteroides, Lactobacilli, Fusobacterium fusiformis, S.aureus, S.epidermis & candida albicans. The bactericidal effect was determined by the enumeration of viable bacterial colonies. Time of irradiation was 20 mibns and frequency 3000 Hz with power 5 watt. Toluidine Blue is selected as a photosentisizer.Results: Ga-As laser irradiation with energy density 1.8j/cm2 resulted in 31.3% mean reduction in CFU number of S.mutans, 30.2% in Diphtheroid, 36.7% in S.epiedermis, 19.2% in Neisseria, 37% in B.melaninogenicus, 32% in Fusobacterium and 44.9% in candida albicans.Conclusion: Ga-As low power laser can be used in preventive dentistry or in treatment of oral lesions.

The complex cis-dioxo-bis[3-methoxy-2, 2-dimethylpropanediamine] molybdenum(VI) (cis-[Mo(O)2L]) and toluidine blue O (TBO) are used for modification of carbon paste electrode (CPE). In order to study of the electrochemical behavior of ascorbic acid (AA) and dopamine (DA) at the surface of the modified CPEs, the differential pulse and cyclic voltammetric methods (DPV and CV) were used. These results reveal that by application of the modified CPE a peak resolution about 329 mV is obtained for AA and DA and the limits of detection (S/N=3) were 1×10− 7 M and 4×10− 7 M for DA and AA, respectively. Surface regeneration and the very easy preparation of the modified CPE together with the very good peak resolution and sub-micromolar detection limits designate the prepared CPE in this work appropriate for simultaneous voltammetric determination of DA and AA. The modified CPE was used successfully for recovery of the analytes in human plasma samples.

Introduction: Antimicrobial photodynamic therapy (aPDT) as a supplement to the conventional root canal preparation has shown promising results. Previous studies have adopted various combinations of light sources and photosensitizers, which makes it difficult to compare the disinfection efficacy of different PDT protocols. The aim of the present study was to compare the efficacy of three photosensitizers (toluidine blue, methylene blue, and curcumin) in PDT using LED against Enterococcus faecalis in root canal disinfection. Methods: Root canals of 54 single-rooted extracted teeth were prepared using the ProTaper Gold rotary system and were incubated with E. faecalis for three weeks. They were then randomly divided into five experimental groups and a control group: (1) Irrigation with 2. 5% NaOCl for 30 seconds, (2) NaOCl irrigation followed by TB-PDT, (3) NaOCl irrigation followed by MB-PDT, (4) NaOCL irrigation followed by curcumin-PDT, (5) Curcumin solvent (1% ethanol+1% BSA), (6) Control (irrigation with normal saline). Sampling was done by collecting dentin shavings from the root canals, and colony-forming units were determined for each treatment group. The data were analyzed by Kruskal-Wallis and Mann-Whitney U tests. The significance level was set at P˂ 0. 05. Results: In all treatment groups, the mean values of colony forming unit (CFU) decreased by 99% compared to the control group. The lowest mean values of CFU were observed in groups 2 and 4, followed groups 3, 1, and 5 respectively. The mean CFU count in group 2 was significantly lower than that of group 1 (P value=0. 011), while there were no significant differences among groups 1, 3, and 4 (P value >0. 05). Conclusion: The adjunction of toluidine blue-mediated PDT by means of a light-emitting diode to NaOCl irrigation increased its antibacterial efficacy against E. faecalis and could be an effective complementary method in root canal disinfection.

Background: Male infertility is defined as a man lost his ability to fertilize a fertile female naturally. Diagnosis of male infertility cannot be made just according to basic semen analysis. It is necessity to have specific tests for evaluation of chromatin in-tegrity. In this study, an attempt was made to evaluate the sperm chromatin quality in fertile men and infertile subgroup. Methods: Among 1386 couples, 342 men were categorized into normospermia and 1044 were infertile and they were referred to Yazd Research and Clinical Center for infertility treatment. Standard semen analysis and sperm nuclear maturity tests in-cluding aniline blue (AB) and toluidine blue (TB) staining were done. Data were an-alyzed by SPSS software. The p≤ 0. 05 was considered statistically significant. Results: The mean value of TB staining was significantly higher in infertile group compared to normospermic group (p=0. 005). Mean of sperm normal morphology was lower in idiopathic infertile men in comparison with normozoospermic men (p= 0. 001). The highest negative correlation was obtained between sperm count and AB staining. Progressive motility was negatively correlated with AB and TB staining in both groups but there was no significant difference between AB staining and pro-gressive motility in men normospermia group. Conclusion: Sperm chromatin staining using AB and TB showed a negative associa-tion between sperm chromatin condensation with sperm count, normal morphology and progressive motility. It seems that the AB and TB test may be useful for the as-sessment of male fertility potential.

Introduction: Oral Candidiasis is the most common lesion in Immuno compromised patients. Using antifungal drugs are routine treatment for this condition. The aim of this study was incorporating photodynamic therapy with low level laser (685 nm), in presence of 2 dyes (methylene blue and tolidine blue), as a photosensitizer on C. albilcans, C. glabrata. C. krusie and C. tropicalis.Methods: In this experimental study, 60 samples (10 samples in 6 groups) from candida suspension were radiated with laser (685 nm–28 j/cm2) in presence or absence of methylene blue or toluidine blue. 0.1 mg/ml from each sample serial dilutions of 10-2 and 10-3 were obtained and aliquots of 0.1 m/ of each dilution were cultured on saburaual dextrose agar. After incubation at 37oC for 48 h, the number of colony (CFU/ml) was counted. ANOVA was used for statistical analysis.Results: Low level laser in presence of methylene blue reduced the number of CFU/ml in 83.2% for C. albicame and toluidine blue as 88.6%.Conclusion: Our invitro study findings show that low level laser in presence of dye (toluidine blue more effective than methylen blue) can reduce the number of candida.

The poly (toluidine blue) modified carbon paste electrode (MCPE) was fabricated for the determination of catechol (CC) and hydroquinone (HQ) by cyclic voltammetric and differential pulse voltammetric techniques. The poly (toluidine blue) MCPE exhibited high sensitivity and selectivity towards the determination of CC and HQ in a binary mixture. The effect of scan rate reveals an adsorption controlled phenomenon at the modified electrode surface. In order to show the selectivity of the electrode, an interference study was performed by varying the concentration of one analyte while keeping other analyte constant which in turn gives a satisfactory result. Overall, a simple experimental procedure for fabricating the poly (toluidine blue) MCPE was reported with the merits of sensitivity, selectivity, reproducibility and anti-fouling property towards the determination of electroactive species.