Chapter 1. Antimicrobial Photodynamic Therapy: Basic Principles

Jori, Giulio; Camerin, Monica; Soncin, Marina; Guidolin, Laura; Coppellotti, Olimpia

doi:10.1039/9781849733083-00001

Cited by 27 publications

(29 citation statements)

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“…In this study an easy and efficient synthetic approach to obtain three new cationic phthalocyanines based on nucleophilic substitutions of commercial available precursors by 4-mercatopyridine is described. This selection was based on the knowledge that pyridine units after being quaternarized by alkylation can confer an efficient antimicrobial photosensitizing activity (27). The neutral derivatives 3 and 4 were obtained respectively from the nucleophilic substitution of the 4-nitrophthalonitrile and 4,5-dichlorophthalonitrile with the selected pyridine derivative followed by the tetramerization step.…”

Section: Discussionmentioning

confidence: 99%

“…Thiolsubstituted phthalocyanine complexes are known to absorb light at higher wavelengths (>700 nm) and to present good photochemical and spectroscopic properties (25,26). Although Gram-positive bacteria are generally susceptible to the most PS used in conventional PDT (27)(28)(29), a different situation is reported for the Gram-negative bacteria, that in general are insensitive to photodynamic effects in the presence of neutral or anionic PS (30)(31)(32). The different susceptibility to the photodynamic process between the two types of bacteria is due to structural differences on their cell wall.…”

Section: Introductionmentioning

confidence: 99%

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Phthalocyanine Thio‐Pyridinium Derivatives as Antibacterial Photosensitizers^†

Pereira

Carvalho

Faustino

et al. 2012

Photochem & Photobiology

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This study describes the synthesis of three new tetra‐ and octa‐thio‐pyridinium phthalocyanine derivatives. PSs 3a and 4a were prepared from the tetramerization of phthalonitriles 1 and 2, respectively, whereas PS 5 was prepared from the nucleophilic substitution of the 8 beta fluor atoms of hexadecafluorophthalocyaninatozinc(II) by mercaptopyridine, followed by cationization. The recombinant bioluminescent Escherichia coli strain was used to assess, in real time, the photoinactivation efficiency of these cationic phthalocyanines, under white and red light. The cellular localization and uptake were also determined to assess the potential of the new phthalocyanines as antibacterial agents. Derivative 3a was the most effective PS, causing a 5 logs reduction in bioluminescence after 30 min of irradiation under white or red lights. The photoinactivation efficiency of the phthalocyanine 4a was similar (5 logs reduction in bioluminescence) to that of 3a when irradiated with white light, but the efficiency of inactivation was reduced (2.1 logs reduction in bioluminescence) under red light. The tetra‐substituted phthalocyanine 3a also generates high amounts of singlet oxygen, does not aggregate in PBS and is highly fluorescent, which makes it an effective PS and a promising fluorescent labeling.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phthalocyanine Thio‐Pyridinium Derivatives as Antibacterial Photosensitizers^†

Pereira

Carvalho

Faustino

et al. 2012

Photochem & Photobiology

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“…Positively charged PS, namely cationic porphyrins, are generally more efficient and can act at lower concentrations than neutral and anionic PS [21][22][23][24]. The charge number increases the amphiphilic character of the PS, and consequently its affinity for bacteria, helping its accumulation in the cells [25,26] which is usually accompanied by an increase in the photocytotoxic activity.…”

Section: Introductionmentioning

confidence: 98%

Photodynamic inactivation of Escherichia coli with cationic meso-tetraarylporphyrins – The charge number and charge distribution effects

et al. 2016

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“…These compounds were tested (together with T 4 MPyP) as antimicrobial PS against Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli . The compounds with C10 and C14 chains were found to be the most active PS against both S. aureus and E. coli when excited with broad band white light .…”

Section: Introductionmentioning

confidence: 99%

Amphiphilic tetracationic porphyrins are exceptionally active antimicrobial photosensitizers: In vitro and in vivo studies with the free‐base and Pd‐chelate

Xuan

Huang

Wang

et al. 2019

Journal of Biophotonics

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Antimicrobial photodynamic inactivation (aPDI) employs the combination of nontoxic photosensitizing dyes and visible light to kill pathogenic microorganisms regardless of drug-resistance, and can be used to treat localized infections.A meso-substituted tetra-methylpyridinium porphyrin with one methyl group replaced by a C12 alkyl chain (FS111) and its Pd-derivative (FS111-Pd) were synthesized and tested as broad-spectrum antimicrobial photosensitizers when excited by blue light (5 or 10 J/cm 2 ). Both compounds showed unprecedented activity, with the superior FS111-Pd giving 3 logs of killing at 1 nM, and eradication at 10 nM for Gram-positive methicillin-resistant Staphylococcus aureus. For the Gram-negative Escherichia coli, both compounds produced eradication at 100 nM, while against the fungal yeast Candida albicans, both compounds produced eradication at 500 nM. Both compounds could be categorized as generators of singlet oxygen (Φ Δ = 0.62 for FS111 and 0.71 for FS111-Pd). An in vivo study was carried out using a mouse model of localized infection in a partial thickness skin abrasion caused by bioluminescent Gram-negative uropathogenic E. coli. Both compounds were effective in reducing bioluminescent signal in a dose-dependent manner when excited by blue light (405 nm), but aPDI with FS111-Pd was somewhat superior both during light and in preventing recurrence during the 6 days following PDT. K E Y W O R D S amphiphilic tetracationic porphyrins, antimicrobial photodynamic inactivation, bioluminescence imaging, broad-spectrum activity, palladium-porphyrin, uropathogenic Escherichia coli infection

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Chapter 1. Antimicrobial Photodynamic Therapy: Basic Principles

Cited by 27 publications

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Phthalocyanine Thio‐Pyridinium Derivatives as Antibacterial Photosensitizers^†

Phthalocyanine Thio‐Pyridinium Derivatives as Antibacterial Photosensitizers^†

Photodynamic inactivation of Escherichia coli with cationic meso-tetraarylporphyrins – The charge number and charge distribution effects

Amphiphilic tetracationic porphyrins are exceptionally active antimicrobial photosensitizers: In vitro and in vivo studies with the free‐base and Pd‐chelate

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Chapter 1. Antimicrobial Photodynamic Therapy: Basic Principles

Cited by 27 publications

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Phthalocyanine Thio‐Pyridinium Derivatives as Antibacterial Photosensitizers†

Phthalocyanine Thio‐Pyridinium Derivatives as Antibacterial Photosensitizers†

Photodynamic inactivation of Escherichia coli with cationic meso-tetraarylporphyrins – The charge number and charge distribution effects

Amphiphilic tetracationic porphyrins are exceptionally active antimicrobial photosensitizers: In vitro and in vivo studies with the free‐base and Pd‐chelate

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Phthalocyanine Thio‐Pyridinium Derivatives as Antibacterial Photosensitizers^†

Phthalocyanine Thio‐Pyridinium Derivatives as Antibacterial Photosensitizers^†