Effects of divalent cations, EDTA and chitosan on the uptake and photoinactivation of Escherichia coli mediated by cationic and anionic porphyrins

• Autores: Gsponer, Natalia Soledad; Spesia, Mariana Belen; Durantini, Edgardo Néstor
• Año de publicación: 2015
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Chitosan; Escherichia Coli; Photodynamic Inactivation; Porphyrin; Uptake
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The effect of divalent cations, EDTA and chitosan (CS) on the uptake and photoinactivation of Escherichia coli produced by 5,10,15,20-tetrakis(4-N,N,N-trimethylammoniumphenyl)porphyrin (TMAP4+), 5,10-di(4-methylphenyl)-15,20-di(4-N,N,N-trimethylammoniumphenyl)porphyrin (MPAP2+) and 5,10,15,20-tetra(4-sulphonatophenyl)porphyrin (TPPS4-) were examined under different conditions. These porphyrins were rapidly bound to E. coli cells (<2.5min) and the uptake of photosensitizers was not dependent on incubation temperature, reaching values of 0.61, 0.18 and 0.08nmol/108 cells for TMAP4+, MPAP2+ and TPPS4-, respectively. The addition of Ca2+ or Mg2+ to the cultures enhanced the uptake of MPAP2+ and TPPS4- by cells. In contrast, the amount of TMAP4+ bound to cells was decreased. The presence of EDTA produced an increase in the uptake of porphyrins by cells, while CS mainly enhanced the amount of TPPS4- bound to E. coli. The photoinactivation of E. coli cells mediated by TMAP4+ was highly effective even at low concentration (1μM) and short irradiation period (5min). However, a reduction in the phototoxicity was found for TMAP4+ in presence of Ca2+ and Mg2+. In contrast, the phototoxic activity mediated by MPAP2+ and TPPS4- was increased. Addition of EDTA did not show effect on the photoinactivation induced by cationic porphyrins, while a small enhance was found for TPPS4-. Moreover, inactivation of E. coli cells was achieved in the presence CS. This cationic polymer was antimicrobial by itself in the dark. Using a slightly toxic CS concentration, the phototoxic activity induced by TMAP4+ was diminished. This effect was mainly observed at lower concentration of TMAP4+ (0.5-1μM). In contrast, an increase in E. coli photoinactivation was obtained for MPAP2+ and TPPS4- in presence of CS. Thus, this natural polymeric destabilizer agent mainly benefited the photoinactivation mediated by TPPS4-.
Fil: Gsponer, Natalia Soledad. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina
Fil: Spesia, Mariana Belen. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina
Fil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina