Photodynamic inactivation of microrganisms with multicharged phythalocyanines

• Autor(a) principal: Rocha, Deisy Mara Gomes da Cruz
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/14268
• topic: Biotecnologia; Microorganismos patogénicos - Fotodegradação; Bioluminescência; Biofilmes; Ftalocianinas; Terapia fotodinâmica

The main goal of this work was to synthesize and characterize new phthalocyanines (Pc) for the photodynamic inactivation of microorganisms. For this, the synthesis of a new family of zinc(II)Pc tetra- and octa- substituted at the peripheral positions was attempt. The compounds were characterized by mass spectrometry and NMR spectroscopy. The inactivation efficiency of six Zinc(II) Pc, tetra- octa- and hexadeca-substituted with DMAP groups was evaluated against a recombinant bioluminescent strain of Escherichia coli in its planktonic form. The experiments were carried out at a concentration of 20 μM of photosensitizer, and either red or white light, with a fluency rate of 150 mW cm-2 as energy source. Assays of photodynamic inactivation of biofilms of the bioluminescent strain were also conducted with red light and the PS that demonstrated better performance in the photodynamic inactivation of free cells. The generation of 1O2, the solubility, fluorescence quantum yield, photostability and cellular uptake were also assessed. Pc 4 and 5 presented the highest inactivation efficiency in the planktonic form of the bioluminescent E.coli, causing reductions of 4 log in their light emission. These molecules were however much less effective against biofilms of the same strain, causing reductions of approximately 2 log in the light emission. In conclusion, Pc 4 and 5 are promising photosensitizers for the photodynamic inactivation of planktonic E.coli, but it still necessary to find ideal conditions for the efficient inactivation of biofilms.