A Simple Experiment to Show Photodynamic Inactivation of Bacteria on Surfaces

D. A. CAMINOS; E. N. DURANTINI

JOHN WILEY & SONS INC

Año: 2007 vol. 35 p. 64 - 64

p style="LINE-HEIGHT: 200%; MARGIN: 0cm 0cm 0pt; tab-stops: 35.4pt" class="MsoFooter">New suitable approaches were investigated to visualize the photodynamic inactivation (PDI) of bacteria immobilized on agar surfaces. The PDI capacities of a cationic [5,10,15,20-tetra(4-N,N,N-trimethylammoniumphenyl)porphyrin] and an anionic [5,10,15,20-tetra(4-sulphonatophenyl)porphyrin] photosensitizers were analyzed on a typical Gram-negative bacterium Escherichia coli following two procedures. In experiment I, the E. coli cells were grown as lawn on agar surface containing the sensitizers spread in a small area (10 nmol in ~0.6 cm2). After irradiation with visible light (10 min, 90 mW/cm2), no cells were grown in the area containing the cationic porphyrin. In experiment II, small colonies (