title: Amphiphilic cationic Zn-porphyrins with high photodynamic antimicrobial activity.
abstract: OBJECTIVE
  Photodynamic inactivation of microbes can efficiently eradicate antibiotic-resistant strains. Systematic structural modification was used to investigate how porphyrin-based photosensitizers (PSs) could be designed for improved antibacterial activity.
  
  
  METHODS
  Zinc(II)5,10,15,20-tetrakis(N-alkylpyridinium-2(3,4)-yl)porphyrins presenting systematic modifications at the periphery of the porphyrin ring were evaluated for toxicity and antimicrobial photodynamic activity by measuring metabolic activity, cell membrane integrity and viability using antibiotic-sensitive and resistant Escherichia coli strains as model Gram-negative targets.
  
  
  RESULTS
  Maximal sensitizer uptake, and, upon illumination, decrease of viable bacteria by >6 log10 were achieved by positively charged amphiphilic PSs with longer (six to eight carbon) alkyl substituents.
  
  
  CONCLUSIONS
  Antibacterial photoefficiency (throughout the text photoefficiency has been used as equivalent of photocytotoxic efficacy) can be increased by orders of magnitude by increasing the lipophilicity of cationic alkylmetalloporphyrin PSs.
authors.affiliation: 1Department of Biochemistry, Faculty of Medicine, Kuwait University, PO Box 24923, Safat 13110, Kuwait.
authors.forename: Milini
authors.initials: M
authors.lastname: Thomas
authors.affiliation: 1Department of Biochemistry, Faculty of Medicine, Kuwait University, PO Box 24923, Safat 13110, Kuwait.
authors.forename: James D
authors.initials: JD
authors.lastname: Craik
authors.affiliation: 2Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Artak
authors.initials: A
authors.lastname: Tovmasyan
authors.affiliation: 2Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Ines
authors.initials: I
authors.lastname: Batinic-Haberle
authors.affiliation: 1Department of Biochemistry, Faculty of Medicine, Kuwait University, PO Box 24923, Safat 13110, Kuwait.
authors.forename: Ludmil T
authors.initials: LT
authors.lastname: Benov
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D002412:Cations / Q000737:chemistry / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D050296:Microbial Viability / Q000187:drug effects; D015394:Molecular Structure; D017319:Photosensitizing Agents / Q000737:chemistry / Q000494:pharmacology*; D011166:Porphyrins / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D017967:Zinc Compounds / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D002412:Cations; D017319:Photosensitizing Agents; D011166:Porphyrins; D017967:Zinc Compounds
keywords: antimicrobial photodynamic therapy; photosensitizer; porphyrin; reactive oxygen species; singlet oxygen