Photodynamic antimicrobial chemotherapy through photosensitizers loaded poly-l-glycolic acid on Candida albicans in denture lining material: Release,biological and hardness study

AimThe aim of this in-vitro study was to formulate poly-l-glycolic acid nanoparticles loaded with methylene blue (PLGA-MB) and to characterize their physicochemical features, photosensitizer-release kinetics and antimicrobial efficacy against Candida albicans (C. albicans) after incorporating in polymethyl methacrylate (PMMA) denture lining materials.Material and methodsMB-PLGA nanoparticles were synthesized according to the modified nanoprecipitation method. The morphological characterization of the nanoparticles was studied under scanning and transmission electron microscope. Particle size, surface charge, polydispersity index (PDI) and MB release were evaluated. The effect of 660 nm semiconductor AlGaInP diode laser on C. albicans was studied in vitro. The PMMA was weighed and PLGA free and PLGA-MB were added in the lining material according to the weight percentage as 2.0 wt.% and 5.0 wt.% and tested for the diameter of the inhibition zones of C. albicans growth and shore A hardness.ResultsHomogenous spherical nanoparticles with round morphology with size ranging between 60–80 nm were observed while PLGA-MB were seen to have irregular structure within the nanoparticle under TEM. PLGA-Free was larger in size than the loaded PLGA (∼62 nm) that evidenced reduction in size by adding the MB photosensitizer. PDI recordings reduced from 0.198 for the PLGA-Free nanoparticles to 0.164 for the PLGA-MB nanoparticles. The entrapment efficiency of MB inside PLGA showed an average percentage of ∼75 % uptake that resulted in the overall loading of ∼15 %. An overall inhibition of 78 %, 41 % and 28 % of C. albicans growth was seen with a concentration of 0.1, 0.5 and 1.0 μg/mL, respectively. The application of PLGA nanoparticles loaded with MB evidenced >75 % of C. albicans. MB incorporation did not lead to a clinically relevant change on shore A hardness.ConclusionPLGA loaded with MB is believed to have promising target therapy against C. albicans in denture soft lining materials in terms of PACT in vitro. The synergistic association between PLGA and MB proved enhanced antifungal activity. PLGA-MB could be an important tool in nanobiotechnology and photodynamic therapy for novel formulations with higher antimicrobial efficacy and improved drug delivery from denture soft lining materials.     

Photodynamic inactivation of Candida albicans by a tetracationic tentacle porphyrin and its analogue without intrinsic charges in presence of fluconazole

The photodynamic inactivation mediated by 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]porphyrin (TAPP) and 5,10,15,20-tetrakis[4-(3-N,N,N-trimethylaminepropoxy)phenyl]porphyrin (TAPP⁴⁺) were compared in Candida albicans cells. A strong binding affinity was found between these porphyrins and the yeast cells. Photosensitized inactivation of C. albicans increased with both photosensitizer concentration and irradiation time. After 30 min irradiation, a high photoinactivation (∼5 log) was found for C. albicans treated with 5 μM porphyrin. Also, the photoinactivation of yeast cells was still elevated after two washing steps. However, the photocytotoxicity decreases with an increase in the cell density from 10⁶ to 10⁸ cells/mL. The high photodynamic activity of these porphyrins was also established by growth delay experiments. This C. albicans strain was susceptible to fluconazole with a MIC of 1.0 μg/mL. The effect of photosensitization and the action of fluconazole were combined to eradicate C. albicans. After a PDI treatment with 1 μM porphyrin and 30 min irradiation, the value of MIC decreased to 0.25 μg/mL. In addition, a complete arrest in cell growth was found by combining both effects. TAPP was similarly effective to photoinactivate C. albicans than TAPP⁴⁺. This porphyrin without intrinsic positive charges contains basic amino groups, which can be protonated at physiological pH. Moreover, an enhancement in the antifungal action was found using both therapies because lower doses of the agents were required to achieve cell death.     

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

BackgroundOnychomycosis is a widespread public health problem, in which T. rubrum and T. mentagrophytes is the commenest causative organisms. Current medical therapy has many drawbacks and side effects. Methylene blue (m.b) photodynamic therapy (pdt) proved efficacy but with lengthy sessions.ObjectivesOptimizing methylene blue photodynamic therapy by combination of methylene blue photosensitizer and gold nanoparticles (aunps) in a composite as gold nanoparticles are efficient delivery systems and efficient enhancers of photosensitizers for antifungal photodynamic therapy.Materials and methodsEighty newzealand rabbit (Oryctolagus cuniculus) were used and categorized in eight equal groups as follows; healthy and infection control, composite photodynamic therapy and five comparative groups. Photodynamic therapy was initiated at day three to five post inoculation, for four sessions forty eight hours apart. Each group divided and light exposure at two fluencies; 80 J and 100 J. All groups were investigated macroscopically and microscopically (histopathology and scanning electron microscope) also flowcytometry assessment for cell death and X-ray analysis for gold nanoparticles accumulation in brain and liver tissues were determined.ResultsRecovery from infection approaching 96% in gold nanoparticles + light group, around 40% in methylene blue photodynamic therapy and 34% in composite photodynamic therapy. The observed findings confirmed by apparent decrease of apoptosis, however small amounts of gold nanoparticles detected in brain and liver.ConclusionLight stimulated gold nanoparticles is a promising tool in treatment of onychomycosis.     

Periopathogens differ in terms of the susceptibility to toluidine blue O-mediated photodynamic inactivation

BackgroundThe main goal of periodontal therapy is to eliminate the infection spreading in periodontium. Antimicrobial photodynamic therapy may be applied in order to eradicate pathogens remaining in periodontal tissues after conventional mechanical debridement, to improve the treatment results. The aim of this in vitro study was to evaluate the susceptibility of selected key periopathogens to toluidine blue O-mediated photodynamic inactivation and the influence of photosensitizer’s concentration and light dose on the effectiveness of this process.MethodsFollowing bacterial strains were used in the experiments: Porphyromonas gingivalis ATCC 33277, Aggregatibacter actinomyctemecomitans ATCC 33384, Fusobacterium nucleatum ATCC 10953. Toluidine blue O (TBO) was used in concentration ranging from 0.004 to 0.5 mg/mL. Irradiation was performed by a non-laser red light source.ResultsComplete eradication of P. gingivalis was obtained upon the application of TBO in the concentration of 0.1 mg/mL and the highest light dose. A, actinomycetemcomitans was, in turn, not susceptible to photodynamic inactivation regardless of the dosimetric parameters applied. High viability reductions were also obtained for F. nucleatum, however no complete eradication. The effectiveness of photodynamic inactivation of susceptible periopathogens was dependent on the light dose and photosensitizer’s concentration.ConclusionsPeriopathogens differ in terms of their susceptibility to photodynamic inactivation. Antimicrobial PDT may be valuable in the treatment of those cases of periodontal disease, in which P. gingivalis is a dominating pathogen. Microbiological examination prior to clinical application of aPDT may be recommended.     

Photodynamic therapy and Acyclovir in the treatment of recurrent herpes labialis: A controlled randomized clinical trial

BackgroundHerpes Simplex Virus Type 1 (HSV-1) is one of the most widespread infections that can effect the orofacial region. Recurrent infection is considered a life-long oral health problem, leading to pain, discomfort, and social restriction due to esthetic features when active. Effective therapies are needed. This study aimed to compare photodynamic therapy (PDT), Topical Acyclovir (AC), and the association of both in the healing process and self-reported symptomologies of HSV-1 recurrences.MethodsPatients were randomly assigned into 3 groups (n = 25): PDT (low-power laser, 660 nm, 40 mW, 120 J/cm², 4.8 J, 120 s per point) and methylene blue (0.005 %) as photosensitizer; AC (5%); PDT + AC.Data concerning lesion size, healing time, and self-reported healing parameters, such as pain, tingling, and edema were taken every day up to complete healing for all studied groups.ResultsThere was no significant difference in healing time and pain between groups. AC group showed a significant minor reduction of the lesion compared to the AC-PDT group on day 1. Regarding edema and tingling, the comparison of treatments showed a statistical difference only on day 1, where PDT showed better results.ConclusionWith all the limitations of this study, it can be concluded that only on day 1 PDT showed positive effects in the treatment of herpes lesions in comparison to AC.     

In vitro photodynamic inactivation of Candida spp. by different doses of low power laser light

This study evaluated the efficacy of PDT in photoinactivation of Candida species using methylene blue (MB) and irradiation with a diode laser (660 nm, 40 mW). Suspensions of Candida species were obtained containing 10⁶ cfu/ml, transferred to 96-holes plates and exposed to 03 doses of laser light (60 J/cm², 120 J/cm², 180 J/cm²) in the presence of MB. Additional suspensions were treated with only the MB, the laser light or with 0.85% saline (control groups). After the treatments, 1 μl aliquot of the suspensions was plated in duplicate on SDA. The plates were incubated at 37 °C for 24–48 h and after this period there was the counting of colonies (cfu/ml). The three evaluated doses determined meaningful inactivation of Candida spp. (p < 0.05). The 180 J/cm² dose was the most effective, inactivating 78% of cfu/ml. At a dose of 180 J/cm²C. albicans was the most susceptible specie. PDT has demonstrated effectiveness in the inactivation of Candida spp.     

Efficacy of photodynamic therapy in the inactivation of oral fungal colonization among cigarette smokers and non-smokers with denture stomatitis

ObjectiveThe aim was to assess the efficacy of antimicrobial photodynamic therapy (aPDT) in the inactivation of oral fungal colonization among cigarette smokers and non-smokers with denture stomatitis (DS).MethodsA questionnaire was used to gather demographic information. Clinical oral examination was performed to determine location of denture in the jaws and oral erythematous lesions. Presence of fungal hyphae in smokers and non-smokers was confirmed using exfoliative cytology. In both groups, aPDT was performed and colony forming units per milliliter (CFU/ml) were assessed im both groups at 3-months follow-up. Level of significance was et at P < 0.05.ResultsTwenty-two males with DS (12 smokers and 10 non-smokers) were included. The mean ages of smokers and non-smokers was 73.8 ± 2.5 and 70.5 ± 1.2 years, respectively. The duration and daily frequency of cigarette smoking was 20.6 ± 4.5 years and 12.3 ± 1.5 cigarettes daily, respectively. Smokers and non-smokers had been wearing complete dentures since 6.2 ± 0.8 and 5.8 ± 0.4 years, respectively. At 3-months follow-up, there was a statistically significant decrease in the mean fungal CFU/ml among smokers (25.5 ± 8.3 CFU/ml) compared with their respective baseline values 106.7 ± 6.3 CFU/ml (P < 0.01). Among non-smokers, the mean CFU/ml values were 12.7 ± 0.8 CFU/ml compared with their respective baseline values (93.6 ± 8.4 CFU/ml) (P < 0.01). At 3-months follow-up, fungal CFU/ml levels were statistically significantly higher among smokers (25.5 ± 8.3 CFU/ml) compared with non-smokers (12.7 ± 0.8 CFU/ml) (P < 0.05).ConclusionaPDT is effective in the inactivation of oral fungal colonization among cigarette smokers and non-smokers with. The role of denture is also emphasized.     

Delivery of lipophilic porphyrin by liposome vehicles: Preparation and photodynamic therapy activity against cancer cell lines

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Antiviral photodynamic therapy: Inactivation and inhibition of SARS-CoV-2 in vitro using methylene blue and Radachlorin

IntroductionRecently, the COVID-19 pandemic has spread globally, necessitating the development of new methods for its prevention and treatment. The purpose of this study was to evaluate the antiviral activity of photodynamic therapy (PDT) against SARS-CoV-2 in vitro.MethodsVero E6 cells and SARS-CoV-2 isolated in Russia were used for PDT with methylene blue (MB) and Radachlorin. A continuous laser with wavelength λ = 662 nm in doses of 16 J/cm² and 40 J/cm² laser irradiation was used for PDT of a viral suspension and SARS-CoV-2-infected cells. The direct cytopathogenic effect of SARS-CoV-2 was evaluated via light microscopy to calculate the TCID₅₀ in the samples and perform statistical analysis.ResultsViral suspensions of SARS-CoV-2 that had a TCID₅₀ greater than 10³ were inactivated by PDT in the presence of MB and Radachlorin. Vero E6 cells were protected from 10⁴ TCID₅₀ of SARS-CoV-2 by PDT post infection. The range of protective concentrations was 1.0–10.0 μg/ml and 0.5–5.0 μg/ml for MB and Radachlorin, respectively. Additionally, it was found that MB and Radachlorin also possess significant antiviral activity even without PDT. The 50 % inhibitory concentration (IC₅₀) against 10² TCID₅₀ of SARS-CoV-2 was found to be 0.22 and 0.33 μg/mL with the addition of MB and Radachlorin, respectively, to cells concomitantly with virus, whereas in the case of applying the photosensitizers at 3.5 h post infection, the IC₅₀ was 0.6 and 2.0 μg/mL for MB and Radachlorin, respectively.ConclusionPDT shows high antiviral activity against SARS-CoV-2 when combined with MB and Radachlorin in vitro.     

Photodynamic therapry with curcumin in the reduction of enterococcus faecalis biofilm in bone cavity: rMicrobiological and spectral fluorescense analysis

BackgroundAntimicrobial photodynamic therapy (PDT) has emerged as a therapeutic strategy to conventional procedures using antibiotics.ObjectiveTo evaluate the antimicrobial effectiveness of PDT using blue light emitting diode (LED) associated with curcumin on biofilms of Enterococcus faecalis in bovine bone cavities and also to analyze the presence of these biofilms through spectral fluorescence.Materials and methodsStandardized suspensions of E. faecalis (ATCC 29212) were incubated in artificial bone cavities for 14 days at 36 °C ± 1 °C for biofilm formation. The test specimens were distributed among the four experimental groups (n = 10): L-C- (control), L + C- (LED for 5 min), L-C+ (curcumin for 5 min) and L + C+ (PDT). Aliquots were collected from the bone cavities after treatments and seeded on BHI agar for 24 h at 36 °C ± 1 °C for CFU count. Before and after each treatment the specimens were submitted to spectral fluorescence, whose images were compared in the Image J program. The log10 CFU/mL results were submitted to the Kruskal–Wallis test (5%) and the biofilm fluorescence spectroscopy results were submitted to the Wilcoxon test (5%).ResultsAll treatments presented statistical difference when compared to the control, and PDT was responsible for the largest reduction (1.92 log10 CFU/mL). There was a reduction in the fluorescence emitted after the treatments, with greater statistical difference in the PDT group.ConclusionPDT was efficient in the reduction of E. faecalis biofilms. In all groups post treatment there was a significant reduction of biofilms in the fluorescence spectroscopy images with greater reduction in the PDT group.     

Photodynamic therapy (PDT) - Initiation of apoptosis via activation of stress-activated p38 MAPK and JNK signal pathway in H460 cell lines

Aims

The purpose of this study was to investigate the photoefficacies of protoporphyrin IX (PpIX) generated by drug precursor 5-aminolevulinic acid (ALA) and its hexyl ester (H-ALA) on two human non-small lung carcinoma cell lines (H460/Bcl-2 and H460/neo).

Main methods

Drug uptake and the photoefficacies of PpIX were measured by flow cytometry and MTT assay; while the mode of cell death and alternation of signal transduction pathways were studied with 4′,6-diamidino-2-phenylindole (DAPI) staining and Western blot analysis, respectively.

Key findings

The flow cytometric analysis of H-ALA (5 μM) uptake revealed optimal fluorescent intensity at 8 h incubation, while ALA (0.5 mM) was still far from saturation. The LD₃₀ of H-ALA-PDT was 30 μM, 2 J/cm², while the LD₃₀ of ALA-PDT was 3 mM, 2 J/cm². The dark toxicities mediated by both pro-drug H-ALA and ALA were negligible. By DAPI staining, apoptotic cell death was observed. In addition, by Western blot analysis, H-ALA- and ALA-mediated PDT initiated apoptotic cell death via the up-regulation and activation of p38 mitogen activated protein kinase (MAPK), the stress-activated c-jun N-terminal kinases (JNK) and ERK.

Significance

These results suggested that H-ALA and ALA mediated PDT displayed similar photocytotoxicities towards the two non-small lung cancer cells. Our present study also demonstrates H-ALA or ALA mediated PDT in H460 cells are closely related to the activation of p38 MAPK and JNK signalling pathway.     

The application of antimicrobial photodynamic inactivation on methicillin-resistant S. aureus and ESBL-producing K. pneumoniae using porphyrin photosensitizer in combination with silver nanoparticles

As resistance of bacterial strains to antibiotics is a major problem, there is a need to look for alternative treatments. One option is antimicrobial photodynamic inactivation (aPDI). The pathogenic cells are targeted by a nontoxic photosensitizer while the surrounding healthy tissue is relatively unaffected. The photosensitizer is activated by light of t appropriate wavelength resulting in the generation of reactive oxygen species that are cytotoxic for the pathogens.In this work, the photosensitizer TMPyP and silver nanoparticles (AgNPs) were investigated for their synergistic antibacterial effect. We tested these two substances on two bacterial strains, methicillin-resistant Staphylococcus aureus 4591 (MRSA) and extended-spectrum beta-lactamases-producing Klebsiella pneumoniae 2486 (ESBL-KP), to compare their effectiveness. The bacteria were first incubated with TMPyP for 45 min or 5 h, then irradiated with a LED source with the total fluence of 10 or 20 J/cm² and then placed in a microbiological growth medium supplemented with AgNPs. To accomplish the synergistic effect, the optimal combination of TMPyP and AgNPs was estimated as 1.56–25 μM for TMPyP and 3.38 mg/l for AgNPs in case of MRSA and 1.56–50 μM for TMPyP and 3.38 mg/l for AgNPs in case of ESBL-KP at 45 min incubation with TMPyP and fluence of 10 J/cm². Longer incubation and/or longer irradiation led to a decrease in the maximum values of the photosensitizer concentration to produce the synergistic effect.From this work it can be concluded that the combination of antimicrobial photodynamic inactivation with a treatment including silver nanoparticles could be a promising approach to treat bacterial infection.     

Sub-additive effects of photodynamic therapy combined with erlotinib for the treatment of epidermoid carcinoma: An in vitro study

BackgroundPhotodynamic therapy (PDT) is an antitumour treatment that employs the combination of a photosensitive compound, oxygen and visible light. To improve the antitumour activity of PDT, the present study used the strategy of combining PDT with erlotinib (ERL), a drug frequently used in the treatment of epidermoid carcinoma.MethodsAn MTT cell viability assay was used to evaluate the cytotoxicity of PDT combined with ERL on A431 epidermoid carcinoma cells in vitro. This study evaluated the cytotoxicity of the following treatments: red laser irradiation (660 nm) at different power densities (1.25–180 J/cm²), the photosensitizer methylene blue (MB) at concentrations of 0.39–100 μM, PDT (12.5 μM MB and laser power densities from 1.25 to 180 J/cm²), and PDT (12.5 μM MB and a laser density of 120 J/cm²) plus ERL (1 μM).ResultsThe laser power densities that were tested showed no cytotoxicity in A431 cells. MB showed a dose-dependent cytotoxicity. In PDT, an increase in the dose of light resulted in an increase in the cytotoxicity of MB. In addition, there was a sub-additive effect between PDT and ERL compared to the effect of each therapy alone.ConclusionsThe sub-additive effect between PDT and ERL suggests that their combination may be an important strategy in the treatment of epidermoid carcinoma.     

The use of antimicrobial photodynamic therapy in the successful management of an invasive cervical resorption class 4: A case report with five years follow-up

A 41-year-old male with a dental history of invasive cervical resorption (ICR) was initially treated with a surgical endodontics approach and secondly with antimicrobial photodynamic therapy (aPDT) along with endodontic retreatment. The use of aPDT was essential to promote bacterial reduction in the resorption defect. Combining these techniques allowed for clinical, radiographic, and tomographic success after five years of follow-up.     

Antimicrobial photodynamic therapy using diode laser activated indocyanine green as an adjunct in the treatment of chronic periodontitis: A randomized clinical trial

IntroductionClinical studies have shown the usefulness of antimicrobial photodynamic therapy (aPDT) as an adjunctive in periodontal therapy. These studies did not utilize indocyanine green (ICG) as a recently introduced photosensitizer. The aim of this study was to perform a full-mouth double-blind randomized controlled clinical study to test the efficacy of adjunctive aPDT with ICG compared with scaling and root planing (SRP) alone in chronic periodontitis treatment.Materials and methodsFifty patients were selected for this study. All patients received SRP. Then, each patient was randomly assigned to either the test group (aPDT + SRP) or the control group (SRP). aPDT was performed with a diode laser (wavelength: 810 nm, power: 200 mW) and ICG as photosensitizer. The adjunctive procedure was repeated after 7, 17 and 27 days. The clinical parameters including bleeding on probing (BOP), clinical attachment loss (CAL), plaque index (PI), probing pocket depth (PPD), full mouth plaque score (FMPS) and full mouth bleeding score (FMBS) were measured at baseline and after 1 and 3 months.ResultsThere were no significant differences between two groups at baseline. BOP, PPD and FMBS showed significant improvements in the test group (P ≤ 0.001). In terms of PI, FMPS and CAL, no significant differences were observed between both groups (P ≥ 0.05).ConclusionaPDT as an adjunctive approach yielded complete resolution of inflammation and significant reduction in periodontal pocket depth. However, aPDT had no additional advantages in clinical attachment gain and plaque score.