Journal
PHOTODIAGNOSIS AND PHOTODYNAMIC THERAPY
Volume 12, Issue 1, Pages 67-75Publisher
ELSEVIER
DOI: 10.1016/j.pdpdt.2014.12.004
Keywords
Porphyrin; Uptake; Photodynamic inactivation; Chitosan; Escherichia coli
Categories
Funding
- Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) of Argentina [PIP 112-201101-00256]
- SECYT Universidad Nacional de Rio Cuarto [PPI 18/C400]
- Agencia Nacional de Promocion Cientifica y Tecnologica (FONCYT) [PICT 0714]
- CONICET
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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 (TMAP(4+)), 5,10-di (4-methylphenyl)- 15,20-di (4-N,N,N-trimethylammoniumphenyl)porphyrin (MPAP(2+)) and 5,10,15,20-tetra(4-suphonatophenyl)-porphyrin (TPPS4-) were examined under different conditions. These porphyrins were rapidly bound to E. coli cells (<2.5 min) and the uptake of photosensitizers was not dependent on incubation temperature, reaching values of 0.61, 0.18 and 0.08 nmol/10(8) cells for TMAP(4+), MPAP(2+) and TPPS4-, respectively. The addition of Ca2+ or Mg2+ to the cultures enhanced the uptake of MPAP(2+) and TPPS4- by cells. In contrast, the amount of TMAP(4+) 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 TMAP(4+) was highly effective even at low concentration (1 mu M) and short irradiation period (5 min). However, a reduction in the phototoxicity was found for TMAP(4+) in presence of Ca2+ and me. In contrast, the phototoxic activity mediated by MPAP(2+) 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 TMAP(4+) was diminished. This effect was mainly observed at tower concentration of TMAP(4+) (0.5-1 mu M). In contrast, an increase in E. coli photoinactivation was obtained for MPAP(2+) and TPPS4- in presence of CS. Thus, this natural polymeric destabilizer agent mainly benefited the photoinactivation mediated by TPPS4-. (C) 2014 Elsevier B.V. All rights reserved.
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