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Evaluation of antibacterial properties of novel phthalocyanines against Escherichia coli – Comparison of analytical methods

Paper ID Volume ID Publish Year Pages File Format Full-Text
30302 44468 2014 10 PDF Available
Title
Evaluation of antibacterial properties of novel phthalocyanines against Escherichia coli – Comparison of analytical methods
Abstract

•Some novel cationic phthalocyanines show an antibacterial effect against E. coli.•Cell binding is a key factor influencing phthalocyanine antibacterial activity.•Bacteria treated with cationic phthalocyanines may form cell agglomerates.•Cell agglomeration negatively affects cytometric measurements of total cell counts.•Cell membrane integrity – a sensitive biomarker for measuring antibacterial effect.

We analyzed antibacterial effects of several novel phthalocyanines against Escherichia coli and evaluated the suitability of flow cytometry for the detection of antibacterial effects of phthalocyanines in comparison with routinely used cultivation. After 3 h of exposure under cool white light eight cationic phthalocyanines showed very high antibacterial activity in the concentration of 2.00 mg L−1 and four of them were even efficient in the concentration of 0.20 mg L−1. Antibacterial activity of neutral and anionic compounds was considerably lower or even negligible. No antibacterial effect was detected when bacteria were exposed without illumination. Binding affinity to bacterial cells was found to represent an important parameter influencing phthalocyanine antibacterial activity that can be modified by total charge of peripheral substituents and by the presence of suitable functional groups inside them. Agglomeration of cells observed in suspensions treated with a higher concentration of certain cationic phthalocyanines (the strongest binders to bacterial membrane) affected cytometric measurements of total cell counts, thus without appropriate pretreatment of the sample before analysis this parameter seems not to be fully valid in the evaluation of phthalocyanine antibacterial activity. Cytometric measurement of cell membrane integrity appears to be a suitable and even more sensitive parameter than cultivation.

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Keywords
Phthalocyanines; Photosensitizers; Antibacterial effect; Singlet oxygen; Binding affinity; Flow cytometry; Cultivation techniques; Cell membrane integrity
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Evaluation of antibacterial properties of novel phthalocyanines against Escherichia coli – Comparison of analytical methods
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 138, 5 September 2014, Pages 230–239
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us