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The phthalocyanine zinc(II) and aluminum (III) complexes were studied to photoinactivate the bacterial strains,
Staphylococcus aureus, methacillin-sensitive and methacillin-resistant, Pseudomonas aeruginosa and one yeast Candida albicans. The binding of phthalocyanines to bacteria and fungi cells was evaluated by the means of laserinduced
fluorescence technique. The fluorescent spectra of dyes (650 - 800 nm) after direct excitation (635 nm) were
measured as follows: 1. for the aqua supernatants obtained after 10 min cell incubation with the respected
phthalocyanines (1.6 &mgr;mol.l-1), 2. for the washed from the unbound dye cells, and 3. for the organic extracts from the
three times washed cells. Fluorescent intensities at the emission maximum (~690 nm) were compared to the spectra of
the phthalocyanines in organic solutions. The phthalocyanines uptake data for bacteria and fungi were determined at
different cell densities. Nevertheless the better fluorescence properties of AlPc (fluorescent quantum yield of 0.4
towards 0.3 for ZnPcs) the lower drug accumulation in microorganisms was obtained. PDI results indicated an intensive
lowering of the bacterial survival of both strains of S. aureus treated with cationic ZnPcMe followed by the anionic
ZnPcS, at irradiance of 100 mW cm-2 and fluence rate of 60 J cm-2. More resistant to phototreatment P. aeruginosa and
morphologically complicated yeast C. albicans were successfully inactivated only with cationic ZnPcMe. These data
indicate the promising future application of cationic phthalocyanine in photodynamic inactivation of pathogenic
microorganisms.
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