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Comparison of thiocyanate and selenocyanate for potentiation of antimicrobial photodynamic therapy.
- Source :
-
Journal of biophotonics [J Biophotonics] 2019 Jan; Vol. 12 (1), pp. e201800092. Date of Electronic Publication: 2018 Aug 03. - Publication Year :
- 2019
-
Abstract
- We have previously shown that antimicrobial photodynamic therapy (aPDT) mediated by different photosensitizers (PS) can be potentiated by a variety of inorganic salts. Potassium thiocyanate (KSCN) potentiated aPDT mediated by methylene blue (MB), while potassium selenocyanate (KSeCN) potentiated aPDT mediated by MB, Rose Bengal and the anionic porphyrin 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin dihydrochloride. However, the mechanisms of action that were proposed were fundamentally different. In the present study, we compare these two salts (KSCN and KSeCN) with different light-activated PS and different oxidative reactions for killing gram-positive and gram-negative bacteria. Overall KSeCN was more powerful than KSCN, and worked with a wider range of PS, while KSCN only worked with phenothiazinium salts. KSeCN produced killing when cells were added after light suggesting production of a semistable species called selenocyanogen (SeCN) <subscript>2</subscript> . We tested three different oxidative reactions that can all potentially kill bacteria: lead tetraacetate (Pb[OAc] <subscript>4</subscript> ); Fenton reagent (hydrogen peroxide [H <subscript>2</subscript> O <subscript>2</subscript> ] and ferrous sulfate) H <subscript>2</subscript> O <subscript>2</subscript> and horseradish peroxidase (HRP). In every case, KSeCN was substantially more effective (several logs) than KSCN in potentiating the bacterial killing. We conclude that (SeCN) <subscript>2</subscript> is the mediator for aPDT using KSeCN, while sulfur trioxide radical anion is the mediator for KSCN using phenothiaziums. For H <subscript>2</subscript> O <subscript>2</subscript> /HRP with KSCN, hypothiocyanite is proposed to be the antibacterial agent in the literature, while hyposelenocyanite is said not to exist. Pb[OAc] <subscript>4</subscript> is known to produce (SeCN) <subscript>2</subscript> from KSeCN as well as the analogous (SCN) <subscript>2</subscript> from KSCN. The mediators from Fenton reaction are unclear (pseudohalogen radical ions?) Both KSCN (which occurs naturally in the human body) and KSeCN may be clinically applicable.<br /> (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Subjects :
- Anti-Bacterial Agents chemistry
Cyanates chemistry
Hydrogen Peroxide chemistry
Iron chemistry
Methicillin-Resistant Staphylococcus aureus drug effects
Methicillin-Resistant Staphylococcus aureus radiation effects
Selenium Compounds chemistry
Thiocyanates chemistry
Anti-Bacterial Agents pharmacology
Cyanates pharmacology
Photochemotherapy methods
Selenium Compounds pharmacology
Thiocyanates pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 1864-0648
- Volume :
- 12
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Journal of biophotonics
- Publication Type :
- Academic Journal
- Accession number :
- 29885019
- Full Text :
- https://doi.org/10.1002/jbio.201800092