Effect of polyethylenimine, a cell permeabilizer, on the photosensitized destruction of algae by methylene blue and nuclear fast red

Cathy McCullagh*, Peter K J Robertson

*Corresponding author for this work

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The present study reports the effect a cell permeabilizer, polyethylenimine (PEI) has on the photodynamic effect of methylene blue (MB) and nuclear fast red (NFR) in the presence of hydrogen peroxide (H2O2). The photosensitized destruction of the algae Chlorella vulgaris under irradiation with visible light is examined. The photodynamic effect was investigated under aerobic and anaerobic conditions. The presence of a permeabilizer during the photosensitized destruction of C. vulgaris does not enhance the activity of the MB, MB/H2O2 system or the NFR, NFR/H2O 2 system under aerobic conditions. However under anaerobic conditions we have determined that when a cell permeabilizer was added to the MB/H 2O2 system, the photosensitized destruction of C. vulgaris proceeded via a combination of Type I and Type II mechanisms. The presence of PEI enforces MB/H2O2 to be active toward the destruction of C. vulgaris whether oxygen is present or absent. Under aerobic and anaerobic conditions the activity of NFR was suppressed in the presence of PEI as a result of electrostatic interactions between the photosensitizer and the cell permeabilizer. The decrease in fluorescence recorded is indicative of destruction of the chlorophyll a pigment. 

Original languageEnglish
Pages (from-to)1662-1667
Number of pages6
JournalPhotochemistry and Photobiology
Volume82
Issue number6
DOIs
Publication statusPublished - Nov 2006

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Biophysics

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