scholarly journals Biogenic Gold Nanoparticles Decrease Methylene Blue Photobleaching and Enhance Antimicrobial Photodynamic Therapy

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 623
Author(s):  
Irena Maliszewska ◽  
Ewelina Wanarska ◽  
Alex C. Thompson ◽  
Ifor D. W. Samuel ◽  
Katarzyna Matczyszyn
Keyword(s):  
Methylene Blue ◽  
Gold Nanoparticles ◽  
Photodynamic Therapy ◽  
Bactericidal Effect ◽  
Antimicrobial Photodynamic Therapy ◽  
Plasmon Band ◽  
Escherichia Coli Bacteria ◽  
Average Size ◽  
20 Nm ◽  
Nanoparticle Sizes

Antibiotic resistance is a growing concern that is driving the exploration of alternative ways of killing bacteria. Here we show that gold nanoparticles synthesized by the mycelium of Mucor plumbeus are an effective medium for antimicrobial photodynamic therapy (PDT). These particles are spherical in shape, uniformly distributed without any significant agglomeration, and show a single plasmon band at 522–523 nm. The nanoparticle sizes range from 13 to 25 nm, and possess an average size of 17 ± 4 nm. In PDT, light (from a source consisting of nine LEDs with a peak wavelength of 640 nm and FWMH 20 nm arranged in a 3 × 3 array), a photosensitiser (methylene blue), and oxygen are used to kill undesired cells. We show that the biogenic nanoparticles enhance the effectiveness of the photosensitiser, methylene blue, and so can be used to kill both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The enhanced effectiveness means that we could kill these bacteria with a simple, small LED-based light source. We show that the biogenic gold nanoparticles prevent fast photobleaching, thereby enhancing the photoactivity of the methylene blue (MB) molecules and their bactericidal effect.

scholarly journals Phenothiazinium Photosensitizers Associated with Silver Nanoparticles in Enhancement of Antimicrobial Photodynamic Therapy

Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 569
Author(s):  
Glaucia Rigotto Caruso ◽  
Ludmilla Tonani ◽  
Priscyla Daniely Marcato ◽  
Marcia Regina von Zeska Kress
Keyword(s):  
Methylene Blue ◽  
Silver Nanoparticles ◽  
Photodynamic Therapy ◽  
Antifungal Activity ◽  
Zeta Potential ◽  
Inhibitory Concentration ◽  
Scattering Method ◽  
Antimicrobial Photodynamic Therapy ◽  
Plasmon Band ◽  
Low Concentrations

Antimicrobial photodynamic therapy (APDT) and silver nanoparticles (AgNPs) are known as promising alternatives for the control of microorganisms. This study aims to evaluate the antifungal activity of APDT, particularly by using the association of low concentrations of phenothiazinium photosensitizers (PS) methylene blue (MB), new methylene blue N (NMBN), and new methylene blue N Zinc (NMBN-Zn) in association with biosynthesized AgNPs. The AgNPs were characterized by UV-Vis spectrophotometry, transmission electron microscopy, and the dynamic light scattering method. The minimum inhibitory concentration of compounds in APDT against Candida albicans and Fusarium keratoplasticum was obtained and the Fractional Inhibitory Concentration Index determined the antifungal effect. The toxicity of compounds and associations in APDT were evaluated in Galleria mellonella. The AgNPs presented a surface plasmon band peak at 420 nm, hydrodynamic diameter of 86.72 nm, and zeta potential of −28.6 mV. AgNPs-PS showed a wider and displaced plasmon band peak due to PS ligands on the surface and decreased zeta potential. AgNPs-NMBN and AgNPs-NMBN-Zn associations presented synergistic effect in APDT with 15 J cm−2 against both fungi and did not show toxicity to G. mellonella. Hence, the enhancement of antifungal activity with low concentrations of compounds and absence of toxicity makes APDT with AgNPs-PS a promising therapeutic alternative for fungal infections.

scholarly journals Antimicrobial photodynamic therapy mediated by methylene blue in surfactant vehicle on periodontopathogens

2020 ◽  
Vol 31 ◽  
pp. 101784
Author(s):  
Ana Carolina A.C. Tortamano ◽  
Giuliana G. Anselmo ◽  
Claudio T. Kassa ◽  
Bianca Godoy-Miranda ◽  
Christiane Pavani ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photodynamic Therapy ◽  
Antimicrobial Photodynamic Therapy

scholarly journals Assessment and Characterization of Some New Photosensitizers for Antimicrobial Photodynamic Therapy (aPDT)

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3012 ◽  
Author(s):  
Laura Monica Dascalu (Rusu) ◽  
Marioara Moldovan ◽  
Doina Prodan ◽  
Irina Ciotlaus ◽  
Violeta Popescu ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photodynamic Therapy ◽  
Essential Oil ◽  
Essential Oils ◽  
Cytotoxic Effect ◽  
Gas Chromatography Mass Spectrometry ◽  
Antimicrobial Photodynamic Therapy ◽  
Absorption Bands ◽  
Oregano Essential Oil ◽  
Vis Spectroscopy

The novelty of this study consists on the formulation and evaluation of five complex experimental natural photosensitizers (PS): gel with oregano essential oil (O), gel with methylene blue (AM), gel with a mixture of essential oils (Thieves-H), gel with arnica oil and curcuma extract (CU) and gel with frankincense essential oil (T), used as photosensitizing agents (PS) in antimicrobial photodynamic therapy (aPDT) in the control of microbial biofilm in oral cavity. The experimental PS were characterized by gas chromatography-mass spectrometry (GC-MS), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, cytotoxicity assay, antimicrobial effect and scanning electron microscopy (SEM). The IR spectra of the experimental PS with essential oils exhibit absorption bands due to the presence of water and glycerol in high quantities. The studied compounds had a reduced cytotoxic effect on cell cultures. The lowest cytotoxic effect was observed in experimental PS with oregano essential oil and methylene blue PS. Essential oils with proven antibacterial capabilities used in experimental PS confer antibacterial activity to the gels in which they are incorporated, an activity that may be more efficient use of a PDT therapy. Single bacteria were detected mainly by SEM after 12 h, while aggregate bacteria and micro colonies dominated the samples at 48 h.

scholarly journals Antimicrobial Photodynamic Therapy in the Control of Pseudomonas syringae pv. actinidiae Transmission by Kiwifruit Pollen

2020 ◽  
Vol 8 (7) ◽  
pp. 1022
Author(s):  
Margarida M. Lopes ◽  
Maria Bartolomeu ◽  
Ana T. P. C. Gomes ◽  
Etelvina Figueira ◽  
Ricardo Pinto ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photodynamic Therapy ◽  
Pseudomonas Syringae ◽  
Pollen Germination ◽  
Ex Vivo ◽  
Irradiation Time ◽  
Antimicrobial Photodynamic Therapy ◽  
Bacterial Reduction ◽  
Promising Alternative

Pseudomonas syringae pv. actinidiae (Psa) is a phytopathogen responsible for bacterial canker in kiwifruit plants and can be disseminated through pollen. This study aimed to evaluate the effectiveness of antimicrobial photodynamic therapy (aPDT) in the inactivation of Psa on kiwifruit pollen using New Methylene Blue (NMB) and Methylene Blue (MB) in the presence/absence of potassium iodide (KI). Pollen germination assays were also performed to evaluate if it was affected by aPDT. Higher reduction of Psa was achieved using NMB (5.0 μM) combined with KI (100 mM) in vitro (ca. 8 log CFU mL−1 after 90 min of irradiation), while NMB alone promoted a lower reduction (3.7 log CFU mL−1). The most efficient NMB concentration with KI was used to study the photodynamic efficiency of MB (5.0 μM). MB with KI photo-inactivated Psa more efficiently than NMB, causing the same bacterial reduction (ca. 8 log CFU mL−1) in half the irradiation time (45 min). Therefore, MB was selected for the subsequent ex vivo aPDT assays in pollen. Almost all the Psa cells added artificially to the pollen (3.2 log CFU mL−1) were photo-inactivated (3.1 log CFU mL−1), whereas aPDT had a low effect on pollen natural microorganisms. When KI was added, a significant increase in aPDT effectiveness was observed (4.5 log CFU mL−1). No negative effects were observed in the pollen germination after aPDT. The results show aPDT is an effective and safe method to Psa inactivation on kiwifruit pollen, and MB use is a promising alternative in the control of Psa transmission.

Methylene blue-mediated antimicrobial photodynamic therapy: A novel strategy for digital dermatitis-associated sole ulcer in a cow – A case report

2018 ◽  
Vol 24 ◽  
pp. 121-122 ◽  
Author(s):  
Fábio Parra Sellera ◽  
Ronaldo Gomes Gargano ◽  
Carolina dos Anjos ◽  
Maurício da Silva Baptista ◽  
Martha Simões Ribeiro ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photodynamic Therapy ◽  
Case Report ◽  
Antimicrobial Photodynamic Therapy ◽  
Digital Dermatitis ◽  
Novel Strategy

Morphological and Optical Characterization of Gold Nanoparticles Decorated Porous Silicon

2019 ◽  
Vol 19 (6) ◽  
pp. 3604-3609
Author(s):  
F Severiano ◽  
V. L Gayou ◽  
G García ◽  
J. A Luna-López ◽  
H. Martínez Gutiérrez ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Porous Silicon ◽  
Chemical Etching ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Sem Analysis ◽  
Etching Time ◽  
Si Nanocrystals ◽  
Average Size ◽  
20 Nm

In this article, physical characteristics of porous silicon (PS) obtained by electro chemical etching using HAuCl4 in the electrolyte are described. The morphological and optical features of PS decorated with gold-nanoparticles (AuNPs) were analyzed in function of the chemical etching time. The insertion of AuNPs inside the PS were performed simultaneously with the formation of the porous silicon layer. Scanning electron microscopy (SEM) analysis showed the formation and incorporation of AuNPs with an average size of 20 nm in the PS structure, which has a pore size of 1.5 μm. Also, it was possible to observe the loss of Si in function of the etching time. Photoluminescence spectroscopy analysis shows a decreasing of the PL intensity, which can be related to the presence of oxygen in the samples. Raman spectroscopy was used to estimate the size of the Si nanocrystals in the PS structure, which suffers a reduction in size due to the presence of HAuCl4 in the electrolyte.

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