- Breaching the wall: morphological control of efficacy of phthalocyanine-based photoantimicrobials
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An efficient treatment of infections using antimicrobial photodynamic therapy (aPDT) anticipates that uptake of photosensitizer (PS) by bacterial cells is very fast and effective. In this work, the design, synthesis, characterization, and photodynamic activity of amphiphilic, water-soluble zinc(ii)phthalocyanine (Zn(ii)Pc) molecules bearing none, three or six thiophenyl moieties are described. We show that PSs that contain no or flexible substituents on non-peripheral positions can photoinactivate microbes at very low loading concentrations and low light doses. In contrast, a PS derivative that contains non-flexible substituents is rendered less effective, despite an increased generation of cytotoxic singlet oxygen, higher lipophilicity and a lower tendency to aggregate. Our unexpected finding emphasizes the role of the morphology of PSs in bacterial cell-molecule interactions and suggests another relevant and hitherto disregarded characteristic to improve PS design.
- Galstyan, Anzhela,Dobrindt, Ulrich
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p. 4630 - 4637
(2018/07/31)
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- Synthesis, electrochemical and photophysical properties of phthalocyaninato oxotitanium(iv) complexes tetra-substituted at the α and β positions with arylthio groups
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The synthesis, electrochemical and photophysical properties of the following tetra-substituted thiol oxotitanium phthalocyanines are reported for the first time: 1,(4)-(tetraphenylthiophthalocyaninato)titanium(iv)oxide (5a); 1,(4)-(tetrabenzylthiophthalocyaninato)titanium(iv)oxide (5b); 2,(3)-(tetraphenylthiophthalocyaninato)titanium(iv)oxide (6a) and 2,(3)-(benzylthiophthalocyaninato)titanium(iv)oxide (6b). Cyclic voltammograms of all four complexes are similar, with three reversible reduction couples each involving a one electron transfer process. The first two reductions were confirmed by spectroelectrochemistry to be metal-based reductions due to Ti IVPc-2/TiIIIPc-2 and Ti IIIPc-2/TiIIPc-2 redox processes, while the last reduction was confirmed to be a ring-based reduction due to TiIIPc-2/TiIIPc-3. Low fluorescence quantum yields (0.05-0.14), relatively long triplet lifetimes (150-210 s) and triplet yields (0.31 to 0.82) were observed. The Royal Society of Chemistry 2006.
- Tau, Prudence,Nyokong, Tebello
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p. 4482 - 4490
(2007/10/03)
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