In Vitro Evaluation of the Antibacterial Effect of Photodynamic Therapy with Methylene Blue

The main objective of this study is to evaluate the antibacterial effect of antibacterial photodynamic therapy (aPDT) on Streptococcus mutans (S. mutans) biofilm model in vitro. The selection of photosensitizers is the key step for the efficacy of photodynamic therapy (PDT). However, no studies have been conducted in the oral field to compare the functional characteristics and application effects of PDT mediated by various photosensitizers. In this research, the antibacterial effect of Methylene blue (MB)/650[Formula: see text]nm laser and Hematoporphyrin monomethyl ether (HMME)/532[Formula: see text]nm laser on S. mutans biofilm was compared under different energy densities to provide experimental reference for the clinical application of the two PDT. The yield of lactic acid was analyzed by Colony forming unit (CFU) and spectrophotometry, and the complete biofilm activity was measured by Confocal Laser Scanning Microscopy (CLSM) to evaluate the bactericidal effect on each group. Based on the results of CFU, the bacterial colonies formed by 30.4[Formula: see text]J/cm2 532[Formula: see text]nm MB-aPDT group and 30.4[Formula: see text]J/cm2 532[Formula: see text]nm HMME-aPDT group were significantly less than those in other groups, and the bacterial colonies in HMME-aPDT group were less than those in HMME-aPDT group. Lactic acid production in all treatment groups except the photosensitizer group was statistically lower than that in the normal saline control group. The activity of bacterial plaque biofilm was significantly decreased in the two groups treated with 30.4[Formula: see text]J/cm2 aPDT. Therefore, aPDT suitable for energy measurement can kill S. mutans plaque biofilm, and MB-aPDT is better than HMME-aPDT.

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Development and in vitro evaluation of BSA-coated liposomes containing Zn (II) phthalocyanine-containing ferrocene groups for photodynamic therapy of lung cancer

Journal of Organometallic Chemistry ◽

10.1016/j.jorganchem.2020.121469 ◽

2020 ◽

Vol 925 ◽

pp. 121469

Author(s):

Özlem Çoban ◽

Burak Barut ◽

Can Özgür Yalçın ◽

Arzu Özel ◽

Zekeriya Bıyıklıoğlu

Keyword(s):

Lung Cancer ◽

Photodynamic Therapy ◽

In Vitro Evaluation

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

Microorganisms ◽

10.3390/microorganisms8071022 ◽

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.

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