SGM: Light-Activated Compounds Kill Bacteria

Activatable dyes, paints kill various types of bacteria
By A. Agrawal, PhD
HealthDay Reporter

WEDNESDAY, Sept. 10 (HealthDay News) -- Light-activated dyes and paints can kill various types of bacteria, according to two studies presented at the Society for General Microbiology meeting held Sept. 8 to 11 in Dublin, Ireland.

In the first study, Ghada Omar, M.D., and colleagues from University College London in the United Kingdom irradiated cultures of Staphylococcus aureus and Streptococcus pyogenes with 98 Joules per square centimeter of near-infrared laser light in the presence of the dye indocyanine green under aerobic and anaerobic conditions. They found that under aerobic conditions, 99.56 percent of S. aureus and 99.96 percent of S. pyogenes were killed, while under anaerobic conditions, 96.77 percent of S. aureus and 71.62 percent of S. pyogenes were killed.

In the second study, Lucia Caballero and colleagues from Manchester Metropolitan University in the United Kingdom examined the effect of different formulations of titanium dioxide-based paint-coated films and fluorescent light on Escherichia coli. They found that 100 percent of the bacteria were inactivated after 96 hours, although this was reduced to 20 percent in the presence of paint additives such as calcium carbonate.

The "results highlight the importance of the composition of paint in the activation of photocatalyst for E. coli killing under fluorescent," Caballero and colleagues conclude.

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