A study of the treatment of cutaneous fungal infection in animal model using photoactivated composite of methylene blue and gold nanoparticle

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.

Nanomaterials enabling clinical translation of antimicrobial photodynamic therapy

Antimicrobial photodynamic therapy (aPDT) has emerged as a promising approach to aid the fight against looming antibiotic resistance. aPDT harnesses the energy of light through photosenstizers to generate highly reactive oxygen species that can inactivate bacteria and fungi with no resistance. To date aPDT has shown great efficacy against microbes causing localized infections in the skin and the oral cavity. However, its wide application in clinical settings has been limited due to both physicochemical and biological challenges. Over the past decade nanomaterials have contributed to promoting photosensitizer performance and aPDT efficiency, yet further developments are required to establish accredited treatment options. In this review we discuss the challenges facing the clinical application of aPDT and the opportunities that nanotechnology may offer to promote the safety and efficiency of aPDT.

Photodynamic therapy-mediated extirpation of cutaneous resistant dermatophytosis with Ag@ZnO nanoparticles: an efficient therapeutic approach for onychomycosis

Aim: The aim of this study was to determine whether photodynamic therapy of resistant onychomycosis with Ag@ZnO nanoparticles can promote the treatment procedure and extirpates the recurrence of fungal infection. Methods: Ag@ZnO nanoparticles (NPs) under UVB-radiation were applied to treat T. rubrum and T. mentagrophytes in vitro through photodynamic therapy. In vivo therapeutic efficacy, biocompatibility and biodistribution of Ag@ZnO NPs were studied. Results: 40 μg/ml of UVB-activated Ag@ZnO NPs showed 100% antifungal activity against dermatophytosis in vitro and in vivo followed by complete growth prevention by degeneration of spores and mycelium after 180 days, while posed biocompatibility. Conclusion: This study showed the superiority of photodynamic therapy with Ag@ZnO NPs followed by proper regeneration of the skin with Zinc ion of the shell.

A nano phototheranostic approach of toluidine blue conjugated gold silver core shells mediated photodynamic therapy to treat diabetic foot ulcer

Diabetic foot infection caused by multidrug-resistant bacteria, is becoming serious problem. Moreover, polymicrobial biofilms contribute significantly to the persistent infections. In the present study, we investigated the effectiveness of novel toluidine blue conjugated chitosan coated gold-silver core-shell nanoparticles (TBO-chit-Au-AgNPs) mediated photodynamic therapy and demonstrate their use as a nontoxic antibacterial therapy to combat diabetic foot ulcer (DFU) caused by multi-drug resistant strains both in monomicrobial and polymicrobial state of infection. In vitro efficacy of TBO-chit-Au-AgNPs mediated photodynamic therapy (PDT) against polymicrobial biofilms was determined using standard plate count method and compared with that of monomicrobial biofilms of each species. Different anti-biofilm assays and microscopic studies were performed to check the efficacy of TBO-chit-Au-AgNPs mediated PDT, displayed significant decrease in the formation of biofilm. Finally, its therapeutic potential was validated in vivo type-2DFU. Cytokines level was found reduced, using nano-phototheranostic approach, indicating infection control. Expression profile of growth factors confirmed both the pathogenesis and healing of DFU. Hence, we conclude that TBO-chit-Au-AgNPs mediated PDT is a promising anti-bacterial therapeutic approach which leads to a synergistic healing of DFU caused by MDR bacterial strains.

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.

Evaluation of the effect of the gold nanoparticles prepared by green ‎chemistry on ‎the ‏treatment of cutaneous candidiasis

Background and Purpose:

Mineral nanoparticle synthesis via green chemistry is ‎considered a novel ‏procedure ‎that ‎has been introduced into some ‏‎‎industries and medical fields. This ‎paper aimed to focus on ‏synthesized gold ‎nanoparticles ‎‎‎‎(‎AuNPs‎) prepared via green chemistry and ‎their usage in the ‏treatment of cutaneous ‎candidiasis.‎‎

Materials and Methods:

This study was performed on the green synthesis of AuNPs using olive leaf extract as a reducing ‎agent‎. The ‎UV‎ visible spectroscopy, X-ray diffraction, and atomic force microscopy techniques ‎were used to detect ‏the concentration of the prepared AuNPs‎. ‎The agar gel diffusion method was used to test ‏the ‎antifungal activity of the ‎‎prepared AuNPs in vitro. ‏Antifungal efficacy of the AuNPs in vivo ‎was tested by the ‎induction of‎‎ cutaneous ‎candidiasis in mice‎.‎This research was conducted on four groups of mice‎. Groups 1 and 2 were used to evaluate the effectiveness of the AuNPs suspension ‎and ‏Nystatin ointment in the treatment ‎of clinical infection, respectively. Groups 3 ‎and ‎4 were the infected ‎and the non-infected control groups, respectively.‎

Results:

Based on the findings, the AuNP synthesis using olive leaves was ‎a suitable and ‎secure method. Moreover, it was found that the AuNPs concentration of 40.77 ng‏\‏ml represented the minimum ‎inhibitory concentration for the ‎inhibition of the Candida albicans. The prepared AuNPs were more effective than Nystatin ‎in the ‏treatment ‎of cutaneous candidiasis.‎‎

Conclusion:

Preparation of AuNPs via green chemistry using olive leaves as a reducing ‎agent is a ‏safe ‎and easy procedure that can be performed to produce AuNPs. In this study, the AuNPs ‎displayed antifungal ‏activity ‏both in vitro and in vivo.‎

Antimicrobial and antibiofilm photodynamic therapy against vancomycin resistant Staphylococcus aureus (VRSA) induced infection in vitro and in vivo

Biofilm mediated infection caused by multi-drug resistant bacteria are difficult to treat since it protects the microorganisms by host defense system, making them resistant to antibiotics and other antimicrobial agents. Combating such type of nosocomial infection, especially in immunocompromised patients, is an urgent need and foremost challenge faced by clinicians. Therefore, antimicrobial photodynamic therapy (aPDT) has been intensely pursued as an alternative therapy for bacterial infections. aPDT leads to the generation of reactive oxygen species (ROS) that destroy bacterial cells in the presence of a photosensitizer, visible light and oxygen. Here, we elucidated a possibility of its clinical application by reducing the treatment time and exposing curcumin to 20 J/cm² of blue laser light, which corresponds to only 52 s to counteract vancomycin resistant Staphylococcus aureus (VRSA) both in vitro and in vivo. To understand the mechanism of action, the generation of total reactive oxygen species (ROS) was quantified by 2'-7'-dichlorofluorescein diacetate (DCFH-DA) and the type of phototoxicity was confirmed by fluorescence spectroscopic analysis. The data showed more production of singlet oxygen, indicating type-II phototoxicity. Different anti-biofilm assays (crystal violet and congo red assays) and microscopic studies were performed at sub-MIC concentration of curcumin followed by treatment with laser light against preformed biofilm of VRSA. The result showed significant reduction in the preformed biofilm formation. Finally, its therapeutic potential was validated in skin abrasion wistar rat model. The result showed significant inhibition of bacterial growth. Furthermore, immunomodulatory analysis with rat serum was performed. A significant reduction in expression of proinflammatory cytokines TNF-α and IL-6 were observed. Hence, we conclude that curcumin mediated aPDT with 20 J/cm² of blue laser treatment (for 52 s) could be used against multi-drug resistant bacterial infections and preformed biofilm formation as a potential therapeutic approach.

Nanoencapsulated hypericin in P-123 associated with photodynamic therapy for the treatment of dermatophytosis

The antifungal application of photodynamic therapy (PDT) has been widely explored. According to superficial nature of tinea capitis and the facility of application of light sources, the use of nanoencapsulated hypericin in P-123 associated with PDT (P123-Hy-PDT) has been a poweful tool to treat this pathology. Thus, the aim of this study was to evaluate the efficiency of P123-Hy-PDT against planktonic cells and in a murine model of dermatophytosis caused by Microsporum canis. In vitro antifungal susceptibility and in vivo efficiency tests were performed, including a skin toxicity assay, analysis of clinical signs by evaluating score, and photoacoustic spectroscopy. In addition, tissue analyses by histopathology and levels of pro-inflammatory cytokines, such as quantitative and qualitative antifungal assays, were employed. The in vitro assays demonstrated antifungal susceptibility with 6.25 and 12.5 μmol/L P123-Hy-PDI; these experiments are the first that have used this treatment of animals. P123-Hyp-mediated PDT showed neither skin nor biochemical alteration in vivo; it was safe for dermatophytosis treatment. Additionally, the treatment revealed rapid improvement in clinical signs at the site of infection after only three treatment sessions, with a clinical score confirmed by photoacoustic spectroscopy. The mycological reduction occurred after six treatment sessions, with a statistically significant decrease compared with untreated infected animals. These findings showed that P123-Hy-PDT restored tissue damage caused by infection, a phenomenon confirmed by histopathological analysis and proinflammatory cytokine levels. Our results reveal for the first time that P123-Hy-PDT is a promising treatment for tinea capitis and tinea corporis caused by M. canis, because it showed rapid clinical improvement and mycological reduction without causing toxicity.

Photodynamic therapy with nanoparticles to combat microbial infection and resistance

Infections caused by drug-resistant pathogens are rapidly increasing in incidence and pose an urgent global health concern. New treatments are needed to address this critical situation while preventing further resistance acquired by the pathogens. One promising approach is antimicrobial photodynamic therapy (PDT), a technique that selectively damages pathogenic cells through reactive oxygen species (ROS) that have been deliberately produced by light-activated chemical reactions via a photosensitiser. There are currently some limitations to its wider deployment, including aggregation, hydrophobicity, and sub-optimal penetration capabilities of the photosensitiser, all of which decrease the production of ROS and lead to reduced therapeutic performance. In combination with nanoparticles, however, these challenges may be overcome. Their small size, functionalisable structure, and large contact surface allow a high degree of internalization by cellular membranes and tissue barriers. In this review, we first summarise the mechanism of PDT action and the interaction between nanoparticles and the cell membrane. We then introduce the categorisation of nanoparticles in PDT, acting as nanocarriers, photosensitising molecules, and transducers, in which we highlight their use against a range of bacterial and fungal pathogens. We also compare the antimicrobial efficiency of nanoparticles to unbound photosensitisers and examine the relevant safety considerations. Finally, we discuss the use of nanoparticulate drug delivery systems in clinical applications of antimicrobial PDT.

Biogenic Silver Nanoparticles Decorated with Methylene Blue Potentiated the Photodynamic Inactivation of Pseudomonas aeruginosa and Staphylococcus aureus

The persistence of multidrug resistance among microorganisms has directed a mandate towards a hunt for the development of alternative therapeutic modalities. In this context, antimicrobial photodynamic therapy (aPDT) is sprouted as a novel strategy to mitigate biofilms and planktonic cells of pathogens. Nanoparticles (NPs) are reported with unique intrinsic and antimicrobial properties. Therefore, silver NPs (AgNPs) were investigated in this study to determine their ability to potentiate the aPDT of photosensitizer against Staphylococcus aureus and Pseudomonas aeruginosa. Biologically synthesized AgNPs were surface coated with methylene blue (MB) and studied for their aPDT against planktonic cells and biofilms of bacteria. The nano-conjugates (MB-AgNPs) were characterized for their size, shape and coated materials. MB-AgNPs showed significant phototoxicity against both forms of test bacteria and no toxicity was observed in the dark. Moreover, activity of MB-AgNPs was comparatively higher than that of the free MB, which concludes that MB-AgNPs could be an excellent alternative to combat antibiotic resistant bacteria.

Methylene Blue-Fortified Molybdenum Trioxide Nanoparticles: Harnessing Radical Scavenging Property

A hybrid nanosystem with impeccable cellular imaging and antioxidant functionality is demonstrated. The microwave irradiation-derived molybdenum trioxide nanoparticles (MoO₃ NPs) were surface-functionalized with the cationic dye molecule, methylene blue (MB), which enables superior UV-visible absorbance and fluorescence emission wavelengths potential for bioimaging. The radical scavenging property of the pristine MoO₃ NPs and MoO₃-MB NPs were studied in vivo using Caenorhabditis elegans as the model system. Heat shock-induced oxidative stress in C. elegans was significantly resolved by the MoO₃-MB NPs, in agreement with the in vitro radical scavenging study by electron paramagnetic resonance spectroscopy. Hybrid nanostructures of MoO₃-MB demonstrate synergistic benefits in intracellular imaging with intrinsic biocompatibility and antioxidant behavior, which can facilitate application as advanced healthcare materials toward bioimaging and clinical therapeutics.

Development of antifungal therapies using nanomaterials

The number and diversity of chemical structures currently available as antibacterial drugs is much higher compared with the number of active substances in relation to pathogenic fungi. In this review we focus on nanotechnology approaches, which offer promising strategies to create nanoagents that possess broad-spectrum antifungal activity and might overcome mechanisms of antibiotic resistance. Special attention was given to magnetic nanoparticles and their ability to restrict fungal growth directly, which depends on surface chemistry and pathogen strains. We speculate that future developments of new antifungal methods will take advantage of the current knowledge of using of magnetic nanomaterials as anticancer agents based on their ability to induce hyperthermia and enhance photosensitizing processes.

Advances in antimicrobial photodynamic inactivation at the nanoscale

The alarming worldwide increase in antibiotic resistance amongst microbial pathogens necessitates a search for new antimicrobial techniques, which will not be affected by, or indeed cause resistance themselves. Light-mediated photoinactivation is one such technique that takes advantage of the whole spectrum of light to destroy a broad spectrum of pathogens. Many of these photoinactivation techniques rely on the participation of a diverse range of nanoparticles and nanostructures that have dimensions very similar to the wavelength of light. Photodynamic inactivation relies on the photochemical production of singlet oxygen from photosensitizing dyes (type II pathway) that can benefit remarkably from formulation in nanoparticle-based drug delivery vehicles. Fullerenes are a closed-cage carbon allotrope nanoparticle with a high absorption coefficient and triplet yield. Their photochemistry is highly dependent on microenvironment, and can be type II in organic solvents and type I (hydroxyl radicals) in a biological milieu. Titanium dioxide nanoparticles act as a large band-gap semiconductor that can carry out photo-induced electron transfer under ultraviolet A light and can also produce reactive oxygen species that kill microbial cells. We discuss some recent studies in which quite remarkable potentiation of microbial killing (up to six logs) can be obtained by the addition of simple inorganic salts such as the non-toxic sodium/potassium iodide, bromide, nitrite, and even the toxic sodium azide. Interesting mechanistic insights were obtained to explain this increased killing.