An in vitro study of the photodynamic effect of rose bengal on Trichophyton rubrum

Exploring the potential and safety of quantum dots in allergy diagnostics

Biomedical investigations in nanotherapeutics and nanomedicine have recently intensified in pursuit of new therapies with improved efficacy. Quantum dots (QDs) are promising nanomaterials that possess a wide array of advantageous properties, including electronic properties, optical properties, and engineered biocompatibility under physiological conditions. Due to these characteristics, QDs are mainly used for biomedical labeling and theranostic (therapeutic-diagnostic) agents. QDs can be functionalized with ligands to facilitate their interaction with the immune system, specific IgE, and effector cell receptors. However, undesirable side effects such as hypersensitivity and toxicity may occur, requiring further assessment. This review systematically summarizes the potential uses of QDs in the allergy field. An overview of the definition and development of QDs is provided, along with the applications of QDs in allergy studies, including the detection of allergen-specific IgE (sIgE), food allergens, and sIgE in cellular tests. The potential treatment of allergies with QDs is also described, highlighting the toxicity and biocompatibility of these nanodevices. Finally, we discuss the current findings on the immunotoxicity of QDs. Several favorable points regarding the use of QDs for allergy diagnosis and treatment are noted.

Photodynamic therapy-mediated hypericin-loaded nanostructured lipid carriers against vulvovaginal candidiasis

INTRODUCTION AND AIM

The indiscriminate use and adverse effects of the main conventional antifungal agents compromise the effectiveness of treating vulvovaginal candidiasis (VVC), mainly caused by the species Candida albicans. This study evaluated the effectiveness of photodynamic therapy (PDT) and the in vitro and in vivo anti-candida potential of the hypericin (HYP)-loaded nanostructured lipid carriers (NLC).

MATERIALS AND METHODS

Empty NLC and NLC-HYP were characterized by the dynamic light scattering technique and transmission electron microscopy to evaluate the average particle size distribution and its morphologies. The in vitro inhibition photodynamic effect of the systems was tested to reduce the planktonic viability of C. albicans. The therapeutic assay photodynamic of the systems was performed to treat VVC in mice.

RESULTS

Empty NLC and NLC-HYP presented values of average hydrodynamic diameter, polydispersity index, and ζ-potential from 136 to 133 nm, 0.16 to 0.22, and -18 to -30 mV, respectively, on day 30. Microscopically, the systems showed spherical morphologies and nanoscale particles. Furthermore, in the in vitro inhibition assay, the treatment of PDT with NLC-HYP (NLC-HYP+) showed a significant reduction of the C. albicans planktonic viability compared to YNB negative control after 5 min of LED light irradiation. In the in vivo therapeutic assay, the antifungal group (vaginal antifungal cream) and NLC-HYP+ evaluated in the dark and by PDT, respectively, had a significant log₁₀ reduction in fungal burden compared to the infected group on day 8 of the VVC treatment.

CONCLUSION

Due to the in vitro and in vivo anti-candida potential, PDT-mediated systems can be an effective strategy in VVC therapy.

Response surface methodological approach for optimization of photodynamic therapy of onychomycosis using chlorin e6 loaded nail penetration enhancer vesicles

Antimicrobial photodynamic inactivation (aPDI) has a tremendous potential as an alternative therapeutic modality to conventional antifungals in treatment of onychomycosis, yet the nail barrier properties and the deep-seated nature of fungi within the nails remain challenging. Therefore, the aim of this study was to prepare, optimize, and characterize Chorin e6 (Ce6) nail penetration enhancer containing vesicles (Ce6-nPEVs) and evaluate their photodynamic mediated effect against Trichophyton rubrum (T.rubrum); the main causative agent of onychomycosis. Optimization of the particle size and encapsulation efficiency of nPEVs was performed using a four-factor two-level full factorial design. The transungual delivery potential of the selected formulation was assessed in comparison with the free drug. The photodynamic treatment conditions for T.rubrum aPDI by free Ce6 was optimized using response surface methodology based on Box-Behnken design, and the aPDI effect of the selected Ce6-nPEVs was evaluated versus the free Ce6 at the optimized condition. Results showed that formulations exhibited high encapsulation efficiency for Ce6 ranging from 79.4 to 98%, particle sizes ranging from 225 to 859 nm, positive zeta potential values ranging from +30 to +70 mV, and viscosity ranging from 1.26 to 3.43 cP. The predominant parameters for maximizing the encapsulation efficiency and minimizing the particle size of Ce6-nPEVs were identified. The selected formulation showed 1.8-folds higher nail hydration and 2.3 folds improvement in percentage of Ce6 up-taken by nails compared to the free drug. Results of the microbiological study confirmed the reliability and adequacy of the Box-Behnken model, and delineated Ce6 concentration and incubation time as the significant model terms. Free Ce6 and Ce6-nPEVs showed an equipotent in vitro fungicidal effect on T.rubrum at the optimized conditions, however Ce6-nPEVs is expected to show a differential effect at the in vivo level where the advantage of the enhanced nail penetration feature will be demonstrated.

Photodynamic Therapy for the Treatment of Fungal Infections

Cutaneous fungal infections are common in humans and are associated with significant physical and psychological distress to patients. Although conventional topical and/or oral anti-fungal medications are commonly recommended treatments, drug resistance has emerged as a significant concern in this patient population, and safer, more efficacious, and cost-effective alternatives are warranted. Recent studies have reported effectiveness of photodynamic therapy (PDT) against fungal infections without severe adverse effects. In this review, we briefly discuss the mechanisms underlying PDT, current progress, adverse effects, and limitations of this treatment in the management of superficial and deep fungal infections.

Photodynamic Therapy-Adjunctive Therapy in the Treatment of Prostate Cancer

The alarming increase in the number of advanced-stage prostate cancer cases with poor prognosis has led to a search for innovative methods of treatment. In response to the need for implementation of new and innovative methods of cancer tissue therapy, we studied photodynamic action in excised prostate tissue in vitro as a model for photodynamic therapy. To ascertain the effects of photodynamic action in prostate tissue, Rose Bengal (0.01 to 0.05 mM) was used as a photosensitizer in the presence of oxygen and light to generate singlet oxygen in tissues in vitro. Five preset concentrations of Rose Bengal were chosen and injected into prostate tissue samples (60 samples with 12 replications for each RB concentration) that were subsequently exposed to 532 nm light. The effects of irradiation of the Rose Bengal infused tissue samples were determined by histopathological analysis. Histopathological examination of prostate samples subjected to photodynamic action revealed numerous changes in the morphology of the neoplastic cells and the surrounding tissues. We conclude that the morphological changes observed in the prostate cancer tissues were a result of the photogeneration of cytotoxic singlet oxygen. The tissue damage observed post photodynamic action offers an incentive for continued in vitro investigations and future in vivo clinical trials.

Photosensitizers Mediated Photodynamic Inactivation against Fungi

Superficial and systemic fungal infections are essential problems for the modern health care system. One of the challenges is the growing resistance of fungi to classic antifungals and the constantly increasing cost of therapy. These factors force the scientific world to intensify the search for alternative and more effective methods of treatment. This paper presents an overview of new fungal inactivation methods using Photodynamic Antimicrobial Chemotherapy (PACT). The results of research on compounds from the groups of phenothiazines, xanthanes, porphyrins, chlorins, porphyrazines, and phthalocyanines are presented. An intensive search for a photosensitizer with excellent properties is currently underway. The formulation based on the existing ones is also developed by combining them with nanoparticles and common antifungal therapy. Numerous studies indicate that fungi do not form any specific defense mechanism against PACT, which deems it a promising therapeutic alternative.

Ellagic Acid Inhibits Trichophyton rubrum Growth via Affecting Ergosterol Biosynthesis and Apoptotic Induction

Background

Trichophyton rubrum, among other dermatophytes, is a major causative agent for superficial dermatomycoses like onychomycosis and tinea pedis, especially among pediatric and geriatric populations. Ellagic acid (EA) and shikonin (SK) have been reported to have many bioactivities, including antifungal activity. However, the mechanism of EA and SK on Trichophyton rubrum has not yet been reported.

Objectives

The purposes of this study were to evaluate the antifungal activities of EA and SK against Trichophyton rubrum and to illuminate the underlying action mechanisms.

Methods

The effect of EA (64, 128, and 256 μg/mL) and SK (8, 4, and 2 μg/mL) on Trichophyton rubrum was investigated with different doses via detecting cell viability, ultrastructure with using a scanning electron microscope (SEM), cell apoptosis and necrosis by using the flow cytometry instrument technique (FCIT), and the ergosterol biosynthesis pathway-related fungal cell membrane key gene expressions in vitro.

Results

SEM detection revealed that the T. rubrum cell surface was shrivelled, folded, and showed deformation and expansion, visible surface peeling, and broken hyphae, and cell contents overflowed after being treated with EA and SK; the cell apoptosis rate was significantly increased in dose-dependent manner after T. rubrum was treated with EA and SK; the qPCR results showed that mRNA expression of MEP4 and SUB1 was downregulated in EA- and SK-treated groups.

Conclusions

Overall, our results revealed the underlying antifungal mechanism of EA and SK, which may be related to the destruction of the fungal cell membrane and inhibition of C14 demethylase and the catalytic rate of squalene cyclooxidase in the ergosterol biosynthesis pathway via downregulation of MEP4 and SUB1, suggesting that EA and SK have the potential to be developed further as a natural antifungal agent for clinical use.

Evaluation of the photodynamic efficacy and effects of haematoporphyrin monomethyl ether on Trichophyton rubrum microconidia in vitro

BACKGROUND

Current available treatment modes against dermatophytoses are often tedious and sometimes unsatisfactory. As an emerging and promising approach, antimicrobial photodynamic therapy (aPDT) attracts much attention in the treatment of superficial or localised infections.

OBJECTIVES

This work investigated the photodynamic efficacy and effects of haematoporphyrin monomethyl ether (HMME) on microconidia of Trichophyton rubrum in vitro.

METHODS

The photodynamic killing efficacy of HMME on microconidia of two T rubrum strains was assessed by MTT assay. The effects of HMME-mediated aPDT on the growth of T rubrum and cellular structure of microconidia were also investigated. Confocal laser scanning microscopy (CLSM) and flow cytometry were employed to study the intracellular localisation of HMME and generation of reactive oxygen species (ROS).

RESULTS

HMME showed no obvious toxicity in the dark, but after light irradiation it inactivated the T rubrum microconidia in a light energy dose-dependent manner, and inhibited the growth of T rubrum. CLSM demonstrated that HMME initially bound to the cell envelop and entered into the cell after light irradiation. HMME-mediated aPDT also damaged the cell cytoplasm and increased the accumulation of intracellular ROS, resulting in cell death.

CONCLUSIONS

The results suggested that HMME-mediated aPDT had potential to be used in the treatment of superficial infections caused by T rubrum.

Clinical retrospective analysis of long-pulsed 1064-nm Nd:YAG laser in the treatment of onychomycosis and its effect on the ultrastructure of fungus pathogen

The objective of this study was to analyze retrospectively the clinical efficacy and fungal clearance of long-pulsed 1064-nm Nd:YAG laser for treating onychomycosis and explore the inhibitory effects of laser on the fungus pathogen-induced onychomycosis in vitro. We performed a systematic retrospective analysis of clinical patients (162 effected nails) of onychomycosis treatment applying laser with or without topical ketoconazole ointment and followed up 3 months after treatment. Trichophyton rubrum- and Trichophyton mentagrophytes-induced onychomycosis was irradiated with laser superimposed for different cumulative energy, respectively; then, the areas of fungus colonies and growth curve in different days were showed, and changes in ultrastructures were observed under SEM and TEM. The clinical effective rate and fungal clearance rate in the combined group were higher than those in the laser group; however, there was no significant difference between the two groups. In vitro, the areas of T. rubrum colonies were significantly reduced at days 1, 3, and 5 after irradiation with cumulative laser energy ≥ 6400 J/cm². When irradiated with cumulative laser energy ≥ 25600 J/cm², significant difference in the areas of T. mentagrophytes colonies was found at day 5. And ultrastructure of the two strains before and after laser irradiation was damaged at different degrees. This study confirmed that long-pulsed 1064-nm Nd:YAG laser is effective for treating onychomycosis, and the laser irradiation can inhibit the colony growth of T. rubrum and T. mentagrophytes and change their cellular ultrastructures. The mechanism of laser treatment of onychomycosis may be related to direct damage of fungus pathogen.

Modern trends in biophotonics for clinical diagnosis and therapy to solve unmet clinical needs

This contribution covers recent original research papers in the biophotonics field. The content is organized into main techniques such as multiphoton microscopy, Raman spectroscopy, infrared spectroscopy, optical coherence tomography and photoacoustic tomography, and their applications in the context of fluid, cell, tissue and skin diagnostics. Special attention is paid to vascular and blood flow diagnostics, photothermal and photodynamic therapy, tissue therapy, cell characterization, and biosensors for biomarker detection.

Photodynamic therapy for onychomycosis: A systematic review

Other than a cosmetic concern, Onychomycosis is also a prevalent nail disease, which is extremely difficult to treat, and sometimes is refractory to conventional therapy. Moreover, many patients are not eligible to take oral antifungals owing to polypharmacy and comorbidities. Systemic side effects seen with oral antifungals have lead to patient nonadherence and adverse events. Therefore, newer therapies are being investigated for onychomycosis that would be free of systemic complications posed by oral therapy. Photodynamic therapy (PDT) is one of those being currently studied, which involves the use of photosensitizer and a light source to excite the photosensitizer to generate reactive oxygen species. The present review will put some light on PDT as an upcoming treatment modality for onychomycosis. We performed a systematic review of the literature to find the articles relevant to the use of PDT for onychomycosis. From the primary search of 43 articles, 17 papers are included in this review.

Synergistic combination of violacein and azoles that leads to enhanced killing of major human pathogenic dermatophytic fungi Trichophyton rubrum

Superficial mycoses caused by dermatophytic fungi such as Trichophyton rubrum represent the most common type of worldwide human infection affecting various keratinized tissues in our body such as the skin, hair, and nails, etc. The dermatophytic infection is a significant public health threat due to its persistent nature and high recurrence rates, and thus alternative treatments to cure this fungal infection are urgently required. The present study mainly focused on the synergistic activity of violacein with four azole drugs (ketoconazole, fluconazole, clotrimazole, and itraconazole) against T. rubrum. The synergistic antifungal activities of violacein and azoles were measured by checkerboard microdilution and time-kill assays. In our study, combinations of violacein and azoles predominantly recorded synergistic effect (FIC index < 0.5). Significant synergistic value was recorded by the combination of violacein and clotrimazole. Time-kill assay by the combination of MIC concentration of violacein and azoles recorded that the growth of the T. rubrum was significantly arrested after 4–12 h of treatment. The combination of violacein and azoles leads to the enhanced inhibition of mycelial growth and conidial germination. Moreover combination enhanced the rate of release of intracellular materials. Morphological changes by SEM analysis were also prominent with the combination. A normal human cell line [Foreskin (FS) normal fibroblast] was used to check the cytotoxicity of violacein. Interestingly violacein recorded no cytotoxicity up to 100 μg/ml. The in vitro synergistic effect of violacein and azoles against clinically relevant fungi, T. rubrum, is reported here for the first time. Finally, our findings support the potential use of the violacein as an antifungal agent especially against dermatophytic fungi T. rubrum.

Effective Single Photodynamic Treatment of ex Vivo Onychomycosis Using a Multifunctional Porphyrin Photosensitizer and Green Light

Onychomycosis is predominantly caused by the dermatophytes Trichophyton rubrum, Trichophyton mentagrophytes and Trichophyton tonsurans. The main treatment obstacle concerns low nail-plate drug permeability. In vitro antifungal photodynamic treatment (PDT) and nail penetration enhancing effectiveness have been proven for multifunctional photosensitizer 5,10,15-tris(4-N-methylpyridinium)-20-(4-(butyramido-methylcysteinyl)-hydroxyphenyl)-[21H,23H]-porphine trichloride (PORTHE). This study investigates single PORTHE green laser/LED PDT of varying degrees of ex vivo onychomycoses in a human nail model. T. mentagrophytes, T. rubrum, T. tonsurans onychomycoses were ex vivo induced on nail pieces at 28 °C (normal air) and 37 °C (6.4% CO₂) during 3 to 35 days and PDTs applied to the 37 °C infections. All dermatophytes showed increasingly nail plate invasion at 37 °C between 7 and 35 days; arthroconidia were observed after 35 days for T. mentagrophytes and T. tonsurans. Using 81 J/cm² (532 nm) 7-day T. mentagrophytes onychomycoses were cured (92%) with 80 µM PORTHE (pH 8) after 24 h propylene glycol (PG, 40%) pre-treatment and 35-day onychomycoses (52%–67%) with 24 h PORTHE (40–80 µM)/40% PG treatment (pH 5). 28 J/cm² LED light (525 ± 37 nm) improved cure rates to 72%, 83% and 73% for, respectively, T. mentagrophytus, T. rubrum and T. tonsurans 35-day onychomycoses and to 100% after double PDT. Data indicate PDT relevance for onychomycosis.

Long term recovery of median nerve repair using laser-activated chitosan adhesive films

Sutures remain the standard peripheral nerve repair technique, whether applied directly or indirectly to nerve tissue. Unfortunately, significant postoperative complications can result, such as inflammation, neuroma formation and foreign body reactions. Photochemical-tissue-bonding (PTB) using rose Bengal (RB) integrated into a chitosan bioadhesive is an alternative nerve repair device that removes the need for sutures. Rats were arranged into three groups: RB-chitosan adhesives-repair, end-to-end epineural suture-repair (surgical standard) and sham laser-irradiated control. Groups were compared through histological assessment, electrophysiological recordings and grip motor strength. RB-chitosan adhesive repaired nerves displayed comparable results when compared to the standard suture-repair based on histological and electrophysiological findings. Functionally, RB-chitosan adhesive was associated with a quicker and more pronounced recovery of grip force when compared to the suture-repair.

In vitro combination therapy using low dose clotrimazole and photodynamic therapy leads to enhanced killing of the dermatophyte Trichophyton rubrum

Background

Superficial infections of the skin and mucous membranes caused by dermatophyte fungi are amongst the most common and challenging infections to treat. Previously we demonstrated the phototoxic effects of photodynamic therapy (PDT) towards Trichophyton rubrum, using a green laser to photoactivate Rose Bengal (RB). The aim of this study was to evaluate whether we could; (1) achieve a similar effect using an inexpensive light-emitting diode (LED) to photoactivate RB and (2) to evaluate whether our PDT regime could be combined with standard antifungal drug therapy and increase its effectiveness.

Methods

We designed and built our own inexpensive green (530 nm) LED source and tested its efficacy as part our RB-PDT regime in vitro against T. rubrum. We also examined the potential benefits of incorporating PDT as part of combination therapy and whether the order in which this was done had an impact. First we subjected spore suspensions to sub-inhibitory concentrations of a number of antifungal agents (CLT, MCZ and TRB) for 72 hours followed by RB-PDT. Secondly we subjected spore suspensions to sub-inhibitory PDT followed by drug treatment and evaluated if there were any changes to the minimum inhibitory concentrations (MICs) of the drugs tested.

Results

The optimal conditions for photoinactivation of T. rubrum using RB-PDT alone were 140 μM of RB and 24 J/cm² of LED (equating to a 30-minute exposure). These parameters also caused a 100% reduction in the viability of the pathogenic yeast Candida albicans and the model fungus Saccharomyces cerevisiae. By combining our RB-PDT regime as an adjunct to antifungal drugs we were able to dramatically reduce the exposure times. Treatment of spore suspensions using a sub-inhibitory dose of clotrimazole (CLT) followed by RB-PDT, this order was critical, significantly reduced the exposure times required to achieve 100% inhibition of T. rubrum to 15 minutes as compared to RB-PDT alone.

Conclusions

The combination of antifungal drug and RB-PDT represents an attractive alternative to the current antifungal therapies used to treat superficial fungal diseases. Our approach has the potential to reduce treatment times and drug dosages which can also reduce drug toxicity and improve patient compliance.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-014-0261-z) contains supplementary material, which is available to authorized users.

An investigation into the inhibitory effect of ultraviolet radiation on Trichophyton rubrum

Fungal infection of nails, onychomycosis, is predominantly caused by Trichophyton rubrum. This infection is an important public health concern due to its persistent nature and high recurrence rates. Alternative treatments are urgently required. One such alternative is phototherapy involving the action of photothermal or photochemical processes. The aim of this novel study was to assess which wavelengths within the ultraviolet (UV) spectrum were inhibitory and equally important nail transmissible. Initial irradiations of T. rubrum spore suspensions were carried out using a tunable wavelength lamp system (fluence ≤3.1 J/cm(2)) at wavelengths between 280 and 400 nm (UVC to UVA) to evaluate which wavelengths prevented fungal growth. Light-emitting diodes (LEDs) of defined wavelengths were subsequently chosen with a view to evaluate and potentially implement this technology as a low-cost "in-home" treatment. Our experiments demonstrated that exposure at 280 nm using an LED with a fluence as low as 0.5 J/cm(2) was inhibitory, i.e., no growth following a 2-week incubation (p < 0.05; one-way ANOVA), while exposure to longer wavelengths was not. A key requirement for the use of phototherapy in the treatment of onychomycosis is that it must be nail transmissible. Our results indicate that the treatment with UVC is not feasible given that there is no overlap between the antifungal activity observed at 280 nm and transmission through the nail plate. However, a potential indirect application of this technology could be the decontamination of reservoirs of infection such as the shoes of infected individuals, thus preventing reinfection.