Photoinactivation of Planktonic and Biofilm Forms of Escherichia coli through the Action of Cationic Zinc(II) Phthalocyanines
authors Lourenco, LMO; Rocha, DMGC; Ramos, CIV; Gomes, MC; Almeida, A; Faustino, MAF; Paz, FAA; Neves, MGPMS; Cunha, A; Tome, JPC
nationality International
journal CHEMPHOTOCHEM
author keywords bacterial resistance; biofilms; phthalocyanines; reactive oxygen species; singlet oxygen
keywords PHOTODYNAMIC ANTIMICROBIAL CHEMOTHERAPY; INACTIVATION; BACTERIAL; THERAPY; MECHANISMS; RESISTANCE; OXIDATION; MEMBRANE; VIRUSES; SYSTEMS
abstract Novel water-soluble zinc(II) phthalocyanines (ZnPc) peripherally substituted with 4-dimethylaminopyridine (DMAP) units (ZnPc 1-2) and the corresponding quaternized derivatives (ZnPc 1a-2a) were synthesized and their photodynamic inactivation (PDI) efficiency against a Gram-negative bacterium, a recombinant bioluminescent Escherichia coli strain either in planktonic or biofilm form, was investigated. The analysis of the photophysical properties revealed that the increase in the number of DMAP units on ZnPc shifted the absorption and emission band in aqueous media to the red region. The presence of multi-positive charges on ZnPc derivatives prevented aggregation and enhances the solubility in aqueous media. The quaternized derivatives ZnPc 1a and 2a displayed good stability and promising efficacy to generate singlet oxygen (O-1(2)). The affinity of the amphiphilic ZnPc 1-2 and quaternized ZnPc 1a-2a to planktonic bacterial cells corresponded to an average uptake of approximate to 10(6)PS molecules.CFU-1. The PDI assays conducted with planktonic cells and biofilms of E. coli show that irradiation with red or white light (150mW.cm(-2)) in the presence of 20M of ZnPc derivatives caused an effective inactivation. ZnPc 1a and ZnPc 2a exhibited the highest inactivation efficiency, particularly of the planktonic form, causing a 5log-scale (99.99%) reduction in bioluminescence. The inactivation factor for biofilms was 99% (2log). ZnPc 1a and ZnPc 2a can be regarded as promising photosensitizers for the photodynamic inactivation of Gram-negative bacteria.
publisher WILEY-V C H VERLAG GMBH
issn 2367-0932
year published 2019
volume 3
issue 5
beginning page 251
ending page 260
digital object identifier (doi) 10.1002/cptc.201900020
web of science category Chemistry, Physical
subject category Chemistry
unique article identifier WOS:000471813800007
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